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 The Outer Limits of Analog Audio

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Sonic Voyager



Posts : 79
Join date : 2018-05-25

PostSubject: The Outer Limits of Analog Audio   Fri Jul 13, 2018 8:57 am



An Unusual 78rpm Sound Box Needle

Sonic found this in Thomas Mayer’s Vinyl Savor blog – within his report on the 2014 European Triode Festival:



Look at the close-up and notice the needle.  I have never seen anything like this!

Sonic did a bit of research. There is a thing called a “trailer needle” – see here:
  https://www.youtube.com/watch?v=dF3WUrP-75g

But if this video is correct from the way the trailer needle is mounted, then the needle in pix from Mayer’s blog cannot be a trailer needle. What might it be?  Perhaps something handcrafted – then again given that you use one needle per side of a 78 rpm record, you will have to make an awful lot of them.

Anyway the best way to play 78 rpm records is to use a suitable phono (MM or MC) cartridge.  Sonic uses a Stanton with a 2.7 mil stylus and has heard how these old records can sound more real than even their LP counterparts and definitely better than digital – as I have learnt to great happiness and to the amazement of many of my audio-friends!

I wonder if the engineers who recorded those 78s all those decades ago in the last century knew what realistic and dimensional sound they were capturing in those grooves? What would the look on their faces be like if we could time travel a group of them and the artistes to 2018 into Michael Green’s listening room and hear their 78s played in that tuned room/system with a Garrard 301, SME 3012 with an Ortofon mono MC cartridge made to play 78s, through the right phonostage EQ?

For Thomas Mayer’s blog, go here:
http://vinylsavor.blogspot.com/

Sonic


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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Sat Jul 14, 2018 10:41 am

For Zonees who might be unfamiliar with 78 rpm sound boxes and the needles, here is a picture of the conventional steel needle design and playing angle for 78 rpm records:



This would show in what way the needle in the picture from Thomas Mayer's blog is unusual.

Sonic


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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Fri Jul 27, 2018 9:46 am

Baerwald Alignment Geometry for 78 rpm Record Playback

Till now, the cartridge alignment geometry that Sonic uses on my Audio Technica AT LP120 with the Stanton 500/5127 has been the Technics SL1200 variant of the Stevenson alignment.

Here is how the Technics/Audio Technica set up is done with a jig or a ruler:



I used this because the logic was that the Stevenson set up has the lowest tracing distortion at the inner grooves at the end of a side.



Source: stereonet.au

The sound I got has been so good that Sonic is now focusing more effort on collecting the old SPs and improving the playback as much as I can (short of buying a new turntable like a Lenco L75).

When properly equalized, the sound of the old mono 78s, particularly voices is eye-poppingly real!

Sonic has recently heard tell of people using the Baerwald geometry for 78s instead of Stevenson. Curious, I changed the set up using the excellent Dr Feickert Protractor



Note from Sonic: here is yet another reason why I like MM cartridges.  Their styli are replaceable. Sonic does not throw away the worn stylus when changing to a new one.  When I change to a fresh stylus, Sonic marks the immediately previous one and keeps it for set up/ alignment purposes as long as the cantilever is straight and the diamond is intact. This is for things like geometry alignments and any that does not involve actually playing a record. So if during the alignment process, an accident happens, it is no big deal.  You cannot do this with your $20,000 Moving Coil cartridge….

And The Improvement in Sound....
The Baerwald setting (compared to the quasi-Stevenson used by Technics and Audio Technica) has the stylus about 3mm further forward in the headshell and slightly more inward twist of the cartridge body…..and what an improvement in sound!

The tone improved, playback is cleaner and there is even further reduction of record noise.

Sonic got out my most difficult 78s – a few 12” broadcast records of classical music with soft passages where record noise sometimes swamped the music – and played them.  Schubert’s Unfinished Symphony and Rossini’s William Tell Overture.  They sound much better now, the ear has an easier job separating out the music from the noise and the old “played to bits” broadcast disks have lower distortion than Sonic imagined.



Sonic


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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Mon Jul 30, 2018 9:26 am



My Experiments with Cartridge Alignment Geometries

Sonic has to tell you that my experiments with alignment geometries led me through an adventure across this last weekend with different conclusions from what I posted here on July 27, 2018.

My cheering the Baerwald setting for 78 rpm and SP replay was premature. Playing more 78 rpm records, the Baerwald alignment indeed sounded clean but the extraordinary lifelikeness of the 78s was gone.  What I got was a clean but artificial sound. Sonic next switched to Stevenson which took me back in the direction of the realism I enjoy from SPs but in the end Sonic started to hear more distortion from this geometry compared to Baerwald.  

What to do?

I then tried the Lofgren B geometry on the Audio Technica and found it a promising middle ground – lower distortion from SPs with a good naturalness especially in voices.  It appears Sonic will have to make some small adjustments in the playback EQ for the 78s in the 250 Hz region. After listening to a larger number of SPs, this alignment is appearing better than the Baerwald setting and cleaner than the Stevenson.  

While I was at it, Sonic next experimented with the geometry of the Rega P5/RB700/Ortofon 2M Blue.

In the case of the Rega/Ortofon, it turns out that Lofgren B sounded preferable over the Baerwald giving a slightly a fuller and better extended sound. So after settling for a couple of days and playing a number of LPs, Sonic is sticking with Lofgren B and this updates my earlier posts on the cartridge alignment geometry I use (see for instance “Tuning and Musical Adventures” June 30, 2017).    

Again a happy thing is I can do my set up with (one generation) older styli of my cartridges so I can get as painstaking as I like without fear of accidentally damaging a fresh stylus. In all these adjustments over the last few days, did Sonic bump anything?  Not at all with the Ortofon, though I did inflict a thump with the Stanton 500 that might set me off wondering if I needed to get the microscope out and see if something broke. But this is a DJ cartridge and a stylus built to DJ standards so this thump was possibly akin to a pat on the head.

In the end, all the cartridge alignment geometries are compromises round the reality of pivoted tonearms swinging in an arc across the record surface while record cutter heads are driven in a straight line across the radius of the disc.  Given that the playback arm tracks in an arc across the record surface, you will have two null points where tangency of the stylus corresponds with the cutting radius thereby creating two Null points where tracing error/distortion is ZERO.

Everywhere else on the record surface the stylus is “in error”.  All the geometries do is to play with overhang and cartridge offset angle (the angle it is mounted in the headshell) to shift the Zero/Null points about distribute the amount of tracing distortion across the surface of the record.  Baerwald (also called Lofgren A) tries for an even distribution, Lofgren B has the least tracing distortion in the middle area but higher tracing distortion at the inner grooves compared to Baerwald/Lofgren A.  Stevenson optimizes for lowest tracing distortion at the inner grooves but is the tracing distortion is higher mostly everywhere else on the record (except the Stevenson Null points) compared to Baerwald and Lofgren B.

What we should however remember that tracing distortion is not necessarily audible as “distortion” as in mistracking.  Whether with Baerwald or now Lofgren B, Sonic does not hear the tracing or any other distortion changing across the groove and I get none of the Inner Groove Distortion that many audiophiles lament about.

The geometry of tonearm/cartridge alignment is a complex topic and because of the inherent compromise involved there are many views about.  There are more set up geometries in addition to the “traditional” (Michael Fremer’s term) geometries of Baerwald, Lofgren B and Stevenson.  There is Uni-Din plus more around including esoteric set up geometries from manufacturers like Japan’s SAEC. In the case of SAEC, their WE-308 arm starts from the outer grooves at something like 6% tracing distortion falling to Zero in the inner grooves. It is a curious system with no Null points. The recommended overhang is 5 mm (typical geometries are twice or three times this) and a small offset angle for the cartridge (around half of what is commonly used elsewhere).

SAEC's rationale, quoted by Phonomac at vinylengine.com, is  “The SAEC WE-308SX arm design is based upon research done by the Sansui Electric Co. The AES preprint 1390 (D-5) derived the optimum pivot position from a kinematic point of view, with the mass of the arm, the location of the center of gravity, and the moment of inertia around the system's center of gravity. Resonance was the engineering problem being solved. For this particular arm, it is not advised to optimize the geometry, or the resonance of the system will change to such an extent that the arm will not track properly.”

For Sonic, I am happy that my tonearms’ set up have been improved on, and I am not going to obsess too much with the arcane geometry of cartridge alignment.  

Sonic


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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Fri Aug 10, 2018 11:36 am

Work to Improve the Audio Technica Turntable - Part 1

Sonic got started on some work to improve my Audio Technica AT-LP 120. Given that I am playing more SPs and 78 rpms as part of my regular listening, Sonic needs to make certain that this cheap 'n' good turntable stays good because that way I can preserve the growing number of 78 rpms and SPs in my collection.

The quality control of the AT-LP 120 is at best adequate, actually not very good (designed in Japan, made in China).  For instance the collar that mounts the headshell to the tonearm is often machined slightly off so that the azimuth of the cartridge is wrong,  and the stylus therefore not vertical to the grooves as seen from the front of the cartridge.



Here is a picture where you can see the locating slots and the tonearm wire contacts slightly rotated clockwise (I shot the picture from an angle that exaggerates the degree of rotation).  Till now, Sonic has compensated for this by mounting the Stanton 500v3/D5127 cartridge used on this arm with a tiny thin washer on one mounting screw between the cartridge top and headshell to bring the stylus back to the perpendicular. This is not a solution I like because it affects the mechanical grounding of the cartridge. Sonic might shortly be using more than one cartridge on this turntable and it means I have shim every headshell and cartridge for this turntable.  The washer on one mounting screw also makes the cartridge hard to align -- the setting runs because the cartridge rotates when you tighten the screws. Very annoying. So its time to try to get this right.

Next, here is a picture of bottom of the arm pillar.



I need to improve the damping of the cueing lever to make it more predictable in its action, rather than working sometimes and other times threatening to slam the cartridge onto the record surface. Which is why Sonic just cues my records by hand. But the cueing level that works is always more convenient and safer.

That will take some work on the square assembly in the upper middle of the circular mount.  In some AT-LP 120s, the tonearm lead-out wires are also badly dressed and that causes horizontal drag on the motion of the arm.  In Sonic’s turntable this wire dressing seems to have been done properly.

And this is a wider picture of the underside of the turntable.



With the AT-LP 120 open, there are a few things that can be done get better sound such as improving the quality of the cable that takes the signal from the tonearm to the phonostage. See the black twinlead snaking through the oblong clip in the lower of the turntable.

Running parallel to this twinlead is a red wire – that is the turntable earth.  I used a heavier gauge earth cable because the original was thin and did not do a good job of grounding the system and a slight hum could be heard.  With the red earth cable, the system is extremely quiet.

More reports to come as work progresses.  

Sonic  




Last edited by Sonic Voyager on Sun Aug 12, 2018 11:37 am; edited 1 time in total
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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Sun Aug 12, 2018 11:36 am

Work to Improve the Audio Technica Turntable – Part 2

Sonic made a good start with this project to improve my Audio Technica AT-LP120!



See the two small screws in the tonearm just behind the headshell locking collar?  They hold the collar mounting assembly.  I removed the screws using a jeweller’s screwdriver and found if I removed the spring washers under the screw heads, the collar can be turned enough to get the headshell about parallel to the record surface.  Sonic tightened the screws (sans washers) as tight I could without stripping the screw threads and on replacing the headshell/cartridge, found the azimuth correct enough.

Next, I tackled the cueing mechanism. This involved applying thick motor grease with a coffee stirrer (used as a spatula) to the lever assembly -- see the square housing in the picture.



I got a cueing mechanism that can be lowered smoothly without crashing the stylus onto the record. Sonic has to control the decent by hand – but this is an improvement!

Finally, Sonic did a test between a rubber mat and a Rega felt mat.  The rubber mat gave a fuller sound possibly by better damping the ringy platter.

Now that the stylus is properly mounted and the stress of the twist from the incorrect azimuth has been removed from the system, Sonic will retest the tonearm alignment geometry again.

I will also get to changing the lead out wires to the phonostage to something that lets through more music.    
 
Sonic

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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Fri Aug 17, 2018 11:03 am

Work to Improve the Audio Technica Turntable – Part 3

Sonic soldered a higher quality cable leading from the turntable to the phono stage. What I had till now was a 24 AWG cable that comes free with a any of a thousand cheap DVD players.  My Audio Technica has reached the stage where Sonic could hear the need for something better.  For this, I found an inexpensive 24 AWG (two conductors) screened Belden cable with Teflon insulation, an 833 something – it is the white wire in this picture.



And Sonic found a Technics 52 mm set up gauge!



So I took some time to retest the arm alignment geometries after the azimuth of the cartridge was fully corrected. I tested Lofgren B vs Stevenson vs the Technics 52 mm setting. After all the recent revisions and improvements, the best sounding and cleanest in terms of perceived distortion and sensitivity to record noise that emerged is the Technics 52 mm setting.  

Sonic is staying with this.

Sonic

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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Fri Aug 24, 2018 8:29 am

Zero-Offset Tonearms

Sonic has been occasionally posting pictures of Japanese tone arms that are absolutely straight with no visible offset angle (the angle the cartridge is turned inward towards the spindle).

I got enough info over time to figure what these Audio Mania Fans were doing.

They are part of a trend of using Zero-Offset Arms with Underhang.
 
Have a look at these pictures of a DIY Japanese tonearm with no cartridge offset angle.



This is from https://audiooyazi.exblog.jp/

The google-translate of the captions to these pictures say:

“Good evening, I made an arm base with a light old material which seems to be sawn lumber of the 1960's. When lightly struck with a finger, it sounds comfortably. I applied linseed oil. Is a nice feeling to check the under hang. Next is the output terminal production and wiring ♪”

Sonic asks “Underhang, Zero Offset Tonearms….what’s going on?”

Audiogon forumer William62 sums up the rationale for these unusual arms like this:


Yes, the alignment is not as good as an off-set arm, but there's the advantage of having no anti-skate problems, and also probably less stress on the cantilever.

Source:
https://forum.audiogon.com/discussions/tonearm-without-off-set

However, Zonees should have a look at the kind of tracing error and distortion an arm like design like this creates.  Notice too there is only one Null point instead of the usual two. If you would like a comparison to how this fares compared to the tracing errors/distortion of the conventional geometries (Baerwald, Lofgren B and Stevenson), have a look at Sonic's post of July 27, 2018 on this thread.

 

This is from
https://www.audioasylum.com/cgi/vt.mpl?f=vinyl&m=1140067

A 500 mm (approximately 19 inches) tonearm is being discussed and the underhang is 6.183mm to minimize distortion.

ViV Laboratories, a Japanese company sells zero-offset tonearms that have lengths of 7 inches to 13 inches.  They are reported to sound pretty good.



Source:
https://www.analogplanet.com/content/will-viv-audio-labs-tonearm-float-your-analog-boat

Fascinating isn’t this?

Sonic



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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Sun Aug 26, 2018 8:20 am

Just as we are discussing zero-offset tonearms, Yamaha launches this – their Gigantic and Tremendous series GT-5000 turntable.


And look at the arm – it is an 8.77 inch long arm with a specified underhang of 17 mm.



Source:
 https://www.monoandstereo.com/2018/08/new-yamaha-gt-5000-turntable_24.html#more
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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Fri Aug 31, 2018 7:40 am


A Mystery Unraveled by Sonic

Zonees will have noticed that Sonic went through a period of mental discombobulation round the alignment geometry for my Rega RB700 tonearm and Ortofon 2M Blue cartridge.  

My account of this was in Sonic’s post of July 30, 2018 where I arrived at the use of Lofgren B…..but there is more.

Background: this all started with Sonic carelessly moving the position of the Ortofon 2M Blue cartridge in the Rega tonearm then trying to aligning it with the Dr Feickert protractor only to find nothing quite got me the sound I enjoyed before the position shift.  

Sonic tried Baerwald (which sounds a little thin), Stevenson (gives a better balance, though with a higher level of distortion was always somewhat audible), Rega’s manufacturer protractor alignment (which was absolutely awful, the most distorted and noisy) and Lofgren B, (which is pretty good, though with perceivably higher end of side distortion is audible).  This was a step backwards from the set up Sonic used previously which was so clean from the first groove to the run-out grooves that even vinyl skeptics had to say “what did you do? I have never heard vinyl analog this distortion free. Your analog is as quiet as CD”

The Mystery Deepens:
a. My Rega RB700 tonearm was set up three years ago by a trusted set up man in one of the best (most reliable) stores in this town

b. I asked for Baerwald and he says he used the Original Dr Feickert Analogue Universal Protractor

c. Sonic has pictures of my Rega RB700 with the old setting and the pictures show where the mounting screws in the headshell were and after the recent attempts at alignment using a Next Generation Dr Feickert Protractor, not one setting of either Baerwald, Stevenson or Lofgren B shared the position of the cartridge mounting screws with the old/original setting! And none of them sound as good.

Look at this -- Baerwald and Lofgren B alignment have the mounting screws at the front of the headshell like this:



The position of the mounting screws of for both Baerwald and Lofgren B are about identical the only difference being the offset angle.

Stevenson on the other hand has the mounting screws just ahead of the halfway point of the slot in the headshell.



For Zonees who are wondering, the Rega manufacturer’s alignment was a little further back from the Stevenson setting, putting the cartridge screws at the mid-point of the slot in the headshell or perhaps a little behind that point towards the arm pivot compared to the Stevenson setting and sounds lousy….really lousy.

The original alignment that worked so well had the mounting screws about an mm or so ahead of Stevenson, slightly offset inward and visibly behind Baerwald/Lofgren B positions!

Sonic was mighty perplexed – what was that mystery setting that worked so good?

Sonic thought deeply into this problem, losing some sleep in the process.

Then as I kept researching (while minimizing Vinyl playback just in case I was damaging the records), Sonic realized that the Baerwald alignment has two variants – IEC and DIN, where the Null Points are (from the record centre): 67mm/122mm and 63mm/119.17mm respectively.  

Stevenson on the other hand has Null Points at 60mm/118mm,  that is closer to the record centre.  Stevenson was designed to minimize inner groove distortion while having somewhat higher tracking distortion elsewhere.  There is rational logic here – the groove speed is lowest at the inner grooves and distortion highest there, so optimize to add the least tracing error there.  SME, VPI and Rega as well as many Japanese manufacturers design their arms round Stevenson or some proprietary variant of it.

Now this set up man is too good a professional to make any gross error.  He must have aligned to something.

Looking at the Null Points of Baerwald IEC, DIN and Stevenson, I noticed the Null Points of Baerwald DIN falls between Baerwald IEC and Stevenson.  With the alignments of Baerwald IEC and Stevenson that Sonic did, I observed that with the same cartridge, a shift of Null Points closer to the centre of the records moves the cartridge back in the Rega headshell…..and noticing that Null Points of Baerwald DIN is between those of Baerwald IEC and Stevenson, Sonic had my “Aha!” moment.

Sonic asked myself “what if the trusted set up man did set up the tonearm for Baerwald as I asked but used Baerwald DIN instead IEC? This setting will put the cartridge in a spot between Baerwald IEC and Stevenson, exactly what Sonic is looking to do!"

The only protractor with a DIN variant for Baerwald (Lofgren B) I could find is the Acoustical Systems SMARTractor that gives both IEC and DIN settings…..and after a few moments, Sonic found that the Baerwald DIN alignment put the mounting screws right back where they were originally.  



The musical sound which Sonic was accustomed to came back, the distortion was lowered and normalcy returned.

Many things Sonic learnt from this:

a.          If something is working well, Do Not Touch It!  

b.          If you have to move something and you cannot afford to lose the setting, at least mark spots, make templates/jigs, take lots of pictures so you can minimize the time you take to get back – this wandering about for Sonic lasted a month!

c.          The different alignment geometries all sound different from each other – even between the IEC and DIN variants of the same geometry, in this case Baerwald. I have to add that Lofgren B have IEC and DIN variants too.

d.          Different protractors, if competently designed, will show proper alignment results where if you get alignment right on one protractor, the other will corroborate it – you will not be right on one and wrong on another

e.          Protractors can vary wildly in ease of use though.  The New Dr Feickert is very easy to use, the Rega card pretty bad (OK, it is alright if your cartridge is square like the Denon 103), while the SMARTractor is real wild given all the reflections though you only had to align to one spot

f.          What a difference a millimeter makes.  That was the difference between the Stevenson and Baerwald DIN (there is more offset angle turn in with the latter), and we talking about both alignments being spot on using precision protractors and magnifiers

g.          Close gets you no cigar.  You must be spot on as determined by magnifiers and not using the naked eye. A setting that is slightly off can increase record ticks and pops noticeably

Sonic has good sound again, and a throbbing headache from eyestrain of using the SMARTractor which is effectively a mirror with grid lines engraved on it.  Imagine linking all that up with a tiny stylus with all the reflections plus the occasional flash of the torchlight beam reflecting all over the place including into Sonic’s eyes.  The SMARTractor is probably the most accurate protractor but not easy to use

This episode has given me an understanding about alignments I did not have till now.  While Sonic loves analog music, I wonder how the future of vinyl playback will go with the need for painstaking set up with costly set-up gear like the protractors I used. No way will one get accurate alignment with a card printed with a few lines and squares.

For the new people entering the joys of analog, I notice they are buying inexpensive plug and play turntables like the Audio Technicas. If these tables come with the manufacturer’s cartridge (like the Audio technical AT95e) properly set up from the factory, then all is well but what happens on the day they change the cartridge for something better?  Where will they get competent help and set up?  I do not see many of the new vinyl fans will want to work to get the DIY skills to do what Sonic just did…..or go to the expense of buying protractors costing multiples of an entry level turntable…..what the future of turntable and vinyl playback then?      

Sonic




Last edited by Sonic Voyager on Fri Aug 31, 2018 10:12 am; edited 2 times in total (Reason for editing : Described the position of the cartridge mounting screws in the headshell for Stevenson and Rega settings more accurately)
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Sonic Voyager



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PostSubject: Re: The Outer Limits of Analog Audio   Fri Sep 28, 2018 10:39 am



An Alternative View on Mono Records

"Many mono recordings are just the same signal recorded on both channels that sum to mono. Mono cutter heads were often not rigid and wobble all over the place at high frequencies. Also the method of the design will affect how much vertical is by default engraved in the cut, Hence my jaundiced view on mono. When mono was all that was available then I accept them at face value."

"Get some old 1950s 78s and play them with a stereo cartridge with right channel wired out of phase then added together so you hear only the vertical or L-R component and be surprise how much rubbish is audible." - Tim de Paravicini

Source: monoandstereo.com


And here is an interview with Tim de Paravicini where there are some ideas for Zonees to ponder:

Tim de Paravicini: Dialing-in the Original Experience

John Atkinson , Stereophile May 2, 2004/First Published: Sep 1, 1990

Meeting Englishman Tim de Paravicini for the first time, you start to wonder if your mind has slipped a gear, whether premature brain fade has cut in. The conversation seems not only to be racing by unexpectedly quickly, but also subjects you hadn't even realized were subjects are being examined in knowledgeable depth. It was at the end of the 1970s that I bumped into Tim at a trade show in the UK; having wanted to ask his opinion of tube-amp design, knowing that the gangling, wispy-bearded, Nigeria-born, one-time resident of South Africa and Japan, ex-Lux engineer (footnote 1) had cast a magic wand over the Michaelson & Austin product line, I found myself instead being treated to an exposition of color phosphor problems in TV monitors. For Tim is a true polymath, his mind seemingly capable of running at high speed along several sets of tracks simultaneously.

But it is in the areas of tube-amp design and transformer winding that he has netted a worldwide reputation. Dick Olsher and Jerry Novetsky interviewed Tim on these subjects for Stereophile back in 1984 (footnote 2) his Esoteric Audio Research (EAR) amplifiers are sought after, particularly in Japan, for their solid-state-esque bass performance; we bought a pair of his natural-sounding tube microphones and an EAR tube mike preamp for use on Stereophile's recording projects; and his HEAD step-up transformer is still remembered by many audiophiles as one of the most musical. These days Tim has been turning his attention to professional audio, in particular the restoration of classic tube tape recorders and analog disc cutting. It was Tim, in fact, who cut the lacquers for Stereophile's Poem album at John Dent's Exchange Studio in London, and he has done excellent work for both Water Lily Acoustics and Chesky Records in the US, and Island Records in the UK. I had lunch with Tim at the 1990 Consumer Electronics Show and started by asking how he'd gotten involved in the high-end industry's sharp end:

Tim de Paravicini: It goes back 20 years, when I was involved with rock and roll bands. Having worked on all aspects of the studio industry, when I ran into John Dent, who was then the cutting engineer for Island, five years ago or so, we got talking and I said, having thought about it over the years, I didn't like the sonic signatures that were being cut onto records. Knowing what master tapes sounded like, I didn't like what the finished products sounded like. John Dent gave me the opportunity to prove that I could design electronics for a cutting system that got rid of the sonic signatures of the cutter head, that I could make a transcription system that had the minimum audio degradation between master tape and playback.

The biggest impact on the sound is the way the motional feedback on the cutter head works. A typical cutter head is a mechanical system with mechanical colorations, the end result being that there is a mechanical "clunkiness," for want of a better description, that I could hear on records. And because it is a mechanical system, the ability to capture detail on the record is also somewhat missing.

Once he'd got agreement from Island (footnote 3), John Dent gave me the funding to go ahead with the project. I spent some three months designing a system that would deal with these problems. The first cutting head I used was a Western Electric, but since, whether they're large or small, they're all basically similar—they all have a pair of drive coils coupled to an amplifier to move the chisel and a pair of feedback coils—the exercise is roughly the same in all cases. Each one, however, has a different sonic signature because of the size and the way it's built.

John Atkinson: And, of course, they're not intrinsically flat in frequency response.

TdP: No, traditionally, stereo cutter heads are designed with a resonance at 1kHz which is used to take care of part of the RIAA net curve; ie, the fact that the cutter head rolls off at 6dB/octave below 1kHz takes care of the 318-microsecond time constant of the RIAA curve. (Ortofon take a slightly different approach to the RIAA correction; the Ortofon cutter head designs are around 2kHz.) So you only need a bit of bass correction for the 50-cycle turnover point. But on the opposite side of 1kHz, you then have to boost massively to put in the RIAA pre-emphasis. Now the cutterhead falls off by some 30 or 40dB by 20kHz, so you've got to actually boost the drive to the cutter head by about 50dB at 20k...

The very old electrical mono cutter heads, such as the Grampian, for 78rpm cutting in the electrical domain rather than the acoustic, were designed in a different way. The original approach was to design a cutter head which had an electrical resonance of somewhere between 10 and 20kHz...78s were therefore cut with what was effectively a flat, constant-velocity characteristic. So driving these old primitive mono cutter heads with an ordinary 10W tube amp, with no correction whatsoever, gave them an approximately ideal characteristic for replay...While they had high-frequency coloration, they actually did a very good job in the midband. But when Neumann came in with motional feedback, they had to design the head a different way...the resonance was brought right downband and then you had what would be called the second-order resonances, which were typically around 10kHz.

JA: The combination would give you this "clunky" sound...

TdP: Yes. What I would call a "quacky" sound. What I specifically did different was how I read the motional feedback signal, how I read the sonic signature of the head, and how I negated it. All my research was done by the simplistic method of bonding a cartridge to a cutter head rather than actually cutting records, in order to cut down time and to avoid wasting lacquers. And immediately I could recognize all the colorations because I was able to treat this as a real-time, line-in/line-out system. The end result was a system that degraded as minimally as possible: ie, the level of comparison, one could say, is that with all my electronics, the replay deck and cartridge, and the replay phono equalization, the degradation is about equivalent to that of putting audio through one 741 op-amp chip. That's my point of reference.

JA: But that sounds terrible! One antique op-amp chip?

TdP: But no other retrieval system can even approach that...no other recording system of any description can come even close to that minimum standard. I'm just trying to put it into context; that to get that far is no mean achievement for a complete system, including a needle, a lump of rock, roughing around in a groove.

JA: Were the cutter heads modified mechanically? Or is it all done electronically?

TdP: They were all electronically fixed. If you do it right, you can make it work. Because the whole point had to be that it had to work with a stock system. It's no good having a system that is not compatible because day-to-day commercial running of the studio means you have to have serviceability and reliability. I have done the same thing with both Neumann and Ortofon heads, and the end product, the record, nobody knows which records were cut with the old Western Electric or which were cut with an Ortofon, or the Neumann. Nobody knows. And I'm not going to tell them which ones are which.

JA: When the studio tried your system out, what was the reaction of the artists?

TdP: Some of John's better clients immediately heard this quality. People like Jim Capaldi's manager, they were aware of it. For one Jim Capaldi record, they were that impressed that, rather than sending copy masters around the world, John had to originate the lacquers for the world production of the record. They wanted all the records pressed to have the same quality. With others, there was a degree of, "It doesn't sound like a lump of vinyl." Their expectations were screwed up, because they'd produce a master tape in the studio, and because they know that they're not going to get the same thing on vinyl, they tend to be artistically pumped up, making something up for the end sound.

JA: My own experience when I was involved in making records was that when the final two-track master was mixed, it never sounded like the way we wanted the record to sound. Only when that same tape was transferred to disc, did it sound right.

TdP: That is a problem with some people. But Dire Straits and one or two other bands do try to produce what I call very pure, very clean sounds.

JA: And then you cut the groove with as clean a signal path as you can.

TdP: Yes, I want to retain the master tape in toto. I want the person out there to experience the same thing that I'm experiencing.
We talked for a while about the problems in obtaining a consistent supply of lacquers, the acetate-covered aluminum blanks on which the cutting engineer enscribes the grooves, and about how lacquers from different companies produce different sounds when the LP is finally pressed from the resultant metalwork. And the metalwork itself presents significant problems. Tim now uses a company in Leicester, England, who've recently installed a new plant:

TdP: Getting good metalwork is a problem. Unfortunately one of the best metal-plating plants in America, Allied, decided to close. EMI in England lost their quality many, many years ago. You see, the problem is with all these processes, because it's a black art it's really the skill of the people involved. Now, the skilled guys at EMI were already pensioned off and buried; the new guys who replaced them hadn't acquired those subtle skills...so those skills have died. There are very, very few places in the world where these traditional black-art skills are maintained.

JA: But surely the basis of economic development in the modern world is that men with skills be replaced by machines that can be operated by relatively unskilled labor? A record company can't stay financially viable if it has to depend on a small number of skilled people in order for its products to be produced. That's one of the reasons why machine-produced CD has been so attractive to these companies—it's a real mass-production medium that doesn't need arcane and archaic skills for it to be produced at an acceptable and consistent level of quality once the capital outlay on the plant has been made.

TdP: That is the whole point. And the point is that there are intangible qualities. If you take a parallel, Rolls-Royce use craftsmen for their cars; no amount of computers and robots can build a car with that indefinable property that a Rolls-Royce, or a Jaguar, or a Mercedes has.

The Japanese, for example, are trying to build fine motorcars that will do everything correctly, but they just don't have that indefinable property that is an art form. You can't become a Rolls-Royce overnight. You can't make a machine do a Picasso. So it depends what you want. Are you after something that is a good art form—you want to do nice music?—or are we going to have it computerized? Instead of buying records, you could just buy a program that plays your MIDI [synthesizer] at home, and you would have electronically recreated music in your home. But it would be sterile; it would be the same as having a speech recognition system that then tells the other end to regenerate a facsimile of your speech, instead of transmitting your voice down the telephone. We are trying to dehumanize this real-time life experience...

JA: And then you're no longer involved with quality.

TdP: Exactly. And this comes down to a commercial decision rather than an artistic decision. The same way that television or FM radio [operates] on a level that satisfies the bulk of people rather than all the people. I personally prefer to have the best. You can either buy cheap pianos or you can buy Steinways. You can either buy a Toyota or an Aston-Martin.

JA: To return to records...

TdP: There was a recent letter from Bob Ludwig in The Absolute Sound. [Issue 61, p.24, about the fact that the one-step process of which TdP is an advocate and which was used for the remastered version of Stereophile's Poem LP is less accurate than the traditional three-step, due to the fact that the freshly cut lacquer has to be sprayed with silver before it can be electroplated to make a stamper, and that that silver layer remains in position on the stamper]. Well, the silvering left on the nickel stamper is literally only of the order of a molecule thick. And that is worn off in the first four stampings or so. Because it is only a molecule thick, it doesn't actually have any tangible degradation because it will still be pulled off, when they plate the interstage, second, and third plate to the final stamper. And the second problem is because of thermal cycling, the fact that the nickel plate, when they grow the second and third generations in the tank, changes temperature. You have a bimetallic action going on. And so you do get problems with the three-step that the one-step doesn't have. Another problem is that no metal deposits absolutely uniformly. So you get grain boundaries that produce a higher noise on the third generation that the first generation doesn't have.

JA: So you feel the one-step process, even with the silver temporarily left on the stamper, is still the more true representation of what was cut into the lacquer.

TdP: It's very good, yes, because this new company [in England], their nickel plating is so good that they're actually doing laser hologram credit-card stampers by exactly the same process. That is molecular-level information. The same as the record.

JA: I think that a lot of people don't realize that the information on an LP can be an order of magnitude smaller than the pits on a CD.

TdP: Exactly. The information on an LP extends down to half a molecule of vinyl. It's a good system provided one takes care. That's the bottom line. I mean, why are people still buying turntables? LP is supposed to be dead.

JA: I understand from talking to some manufacturers at this show that American audiophiles, at least, are not buying as many turntables as they used to.

TdP: They're not buying as many, no. But there are still people buying them. There are still manufacturers of turntables in America.
We continued our conversation with a discussion of Tim's modification of the industry-standard Sony PCM-1630 for CD mastering. While he leaves the digital section alone, he basically rebuilds the analog circuits so that they minimally degrade the sound. (Martin Colloms's Stereophile review of the '1630 in Vol.10 No.5 mentioned that the analog sections of the processor are based on relatively ordinary NE5534 op-amp circuitry.) I asked Tim what CDs had been transferred to digital with his modified 1630.

TdP: Well, all the CDs put out by Charlie Records, See For Miles, and Affinity Records in England, quite a number by Dire Straits, Cat Stevens, Bob Marley, the Wailers, and Lincoln Kwaze Johnson—Island's catalog...And we did Kavi Alexander's CD [Arturo Delmoni performing Bach, Kreisler, and Ysaÿe, Water Lily Acoustics WLA-WS-07CD].

JA: What do you see as the major problems in digital replay and recording?

TdP: We are stuck with a system that has already been formatted by Sony and by Philips 10 years ago. We are well down that road and it's going to be awfully hard to change it. I think perhaps in five years' time, a second, up-market system, like HDTV in television, will happen in digital...That has got to happen. But at the moment I don't think the vested interests wish to have another completely new format.

JA: I could be cynical and say we already have a low-resolution, mass-market medium, which is CD, and an up-market, high-resolution medium, which is the LP.

TdP: That is exactly what I am trying to say. And the LP is still not a finished art. I'm still doing development. Other people are still doing development on cartridges and all the rest of the chain. Because the LP's an analog system, it's not bound by the same limitations of, for example, saying we will have 525 lines, take it or leave it. The parallel is that analog film, Kodak film rolling through a shutter, is actually holding its own. And in England a lot of the newsreel companies are going back to their Arriflexes, because there's a lot of creativity that they can do in film, in celluloid, that they can't do in video.

JA: And if you think that the analog medium, film, offers ten times the line resolution of good video...

TdP: And film is going through continuous improvements. They can improve the definition and the contrast and everything in film without upsetting the compatibility. They can still put it on the same projector. That is the whole crux of it. I think vinyl still can be a viable medium, but it's a matter of how it's [distributed]. The difference is that film and video in the studio industry are used by professionals, so they haven't got to worry about the distribution. Whereas with vinyl and CD, we have to deal with trying to distribute it, to disseminate it, as against keeping it in-house. I mean the same argument can be applied to magazines. Why aren't Hi-Fi News or The Las Vegas Times sold as microfiches? Why don't they get down and print magazines this small and sell people magnifying glasses?

JA: The answer is that the centuries-old format of the magazine is more portable, more easily accessible.

TdP: That's my argument. We should keep with things that are acceptable in human terms. I mean, vinyl is not practical for jogging but there is a time and a place for enjoying music. I don't go jogging when I'm in a concert hall—I may go jitterbugging but I don't go jogging!

JA: Tell me how you set your priorities when you designed EAR's The Mic.

TdP: Was it transparent? Did it capture the whole sound picture? A lot of the traditional microphones, for example, don't have enough bass response. When we're listening to live music in a theater, there is a dimension of the theater that with our eyes closed we could recognize where we were sitting, in the Royal Albert Hall, or the Queen Elizabeth Hall, or Barbican, or wherever. If you're familiar with the buildings, it doesn't take five seconds to realize which one you're in. Most of this is the low-frequency signature, the fundamental reflections of the building, the time decay of the building, and the low-frequency pattern—they all have to be phase coherent for us to recognize it.

JA: The English writer Rex Baldock years ago said that it was in the infrasonic region that the hall signature imposed itself on the music.
TdP: Precisely. And human beings use vibration of the body, as well as what we hear directly through the ears, to build the sonic picture. The tradition that we only hear down to 20Hz is rubbish. We actually perceive sound all the way down to 3Hz. Below which the body cannot experience vibration of any description; the body has designed itself so that we don't hear our own legs when we're walking, or running. The traditional concept should be rewritten to say "Experience of sound extends to 3Hz." But the traditional mike manufacturers tend to consider themselves doing well if they get a bottom E on a bass guitar. Commonly 42Hz. And they say that's fine.

The problem is that those microphones lose some of the information that should be there. So trying to understand the microphone's job is a compound picture. Do we hear? Do we feel what it's supposed to be doing? Even if some consumers haven't got reflexes to experience it all. That's irrelevant. As long as we can produce and inscribe into the finished product all that we can, then it allows those who are in a more privileged position to at least share the experience more validly.

JA: Does that mean that when you cut records, you don't roll off the extreme lows?

TdP: We cut records all the way down to sub-5Hz. So it's a matter of whether the guy's turntable has the correct arm and the correct resonances, and the damping on the arm, whether it retrieves the bottom end accurately or not—that is not for me to judge. As long as it's been inscribed on the record, I know that it can be recovered with the right equipment.

JA: Did you choose to use quite a large Milab capsule to capture that low-frequency information?

TdP: No, the capsule is moderate size. The reason for using the rectangular capsule is that it's more akin to a ribbon microphone, to a line source. Stereophony, bounded by walls, requires two pure line sources to reproduce the stereo picture. If the microphones are effectively line sources—in fact, my next-generation microphone will be even more of a line source, it's going to use a capsule some 2" tall and 5/8" wide—all the HF coloration is reduced in the horizontal plane and that gives us better localization in the horizontal plane. And the same way the head has temporal response—in other words, we hear certain frequencies above the head and in front of the head—I want the microphone to do that so that we can convey more of the dimensions of the sound that we are trying to record. So that we can position the orchestra in three dimensions. Left to right, as well as up and down and back to front.

JA: That's a real area of contention. Most theoreticians say that stereo imaging is only two-dimensional: side to side and front to back.

TdP: Well, we seem to manage to hear very effectively in the real world where a sound has come from pretty well all points of the compass. In other words, if somebody—whisk—comes up to you from behind, you know he's there.

JA: But there is some ambiguity in height perception. It is hard to distinguish whether you are hearing a soundsource directly under your feet or above your head.

TdP: Oh, there are areas of ambiguity, yes. So humans have the ability to turn their heads and try to zero in. But there is [a small enough degree of] ambiguity to at least make our choice error-minimal. We tend to turn our heads in the right direction in the first place.

JA: And that adds rate-of-change information which resolves the ambiguity.

TdP: Yes. But the more we can get that property into the recording, the more we will then have a recording where the head is stationary. In other words, it will have no more and no less realism than what we would experience if our head if we were sitting still in the recording environment. We would go to a holographic experience where we could say, "Let us dial ourselves into the original experience."

JA: To return to the mike, a lot of your design philosophy seems to be very traditional. The use of tubes, and particularly the use of transformer coupling.

TdP: Yes, because I have to be practical and use the mike in a conventional environment where there are long cables and where cables have to be of practical dimensions. It is no good me using cables that are 2" in diameter. And I use a transformer to be able to give me an output that will transmit down a 100 ohm cable correctly...A transformer can achieve consistently high common-mode rejection, it has the ability to withstand high superimposed noise signals...Active balanced circuits have weaknesses which transformers don't have—if designed correctly. The problem is traditionally what I call "wound" transformers that have been compromised too severely.

JA: It's another black art.

TdP: It's a black art. Yes. Likewise, tubes have dynamic properties that transistors don't easily have. And tubes are very rugged; they may have microphony, they may have other disadvantages, but at the end of the day they are extremely robust beasts. And they're not significantly any less efficient than transistor circuits. After all, power is power. You can't squash the watt, as I put it.

JA: A 100W tube amp is around the same physical bulk as a good 100W transistor amp.

TdP: Because heat is heat. I should also say that because tubes are made on a mechanical process, they're actually remarkably consistent.

JA: If you can get the skilled operators to make them—I understand that the Chinese company that's using the old M-O Valve company tooling had a lot of consistency problems in their tubes because of the lack of experience of their operators.

TdP: Experience, yes. But I'm talking about an all-things-being-equal condition.

JA: You do design with transistors for some of your third-party projects, Musical Fidelity, for example.

TdP: Yes, yes. I have no particular personal preference for any medium. Whether it's transistor or tube, each can do its job well. But through EAR I choose to purvey tubes, the same way that Rolls-Royce still purveys large cars and doesn't make small cars. But what I did for other people is less stringent.

JA: You also appear to be a traditionalist in amplifier design in that you reject the use of a lot of voltage regulation. Both your mike preamp and your G88 preamp that you introduced at this show (footnote 4) use traditional power non-regulated voltage supplies.

TdP: Because a good building doesn't require props to keep it up. I take the same approach: if you design the circuitry properly, it doesn't need prosthetic aids.

JA: But can't you see the temptation for designers when a 20-cent, 3-pin chip buys them 50dB of hum rejection?

TdP: Yes, but if I can already achieve that, why do I have to bother? It's as simple as that. And putting a regulated supply on is not going to give me any benefits that I don't have already. It's going to give me disadvantages, because it's going to make the product more susceptible to fragile power sources. Whereas when I have an unregulated system, the product is relatively immune from mains disturbances.

JA: I noticed yesterday you turning your preamp off while it was playing an LP without there being the usual speaker-destroying bangs...

TdP: I can have mains crap-outs for up to a couple of seconds without there being any tangible problem. The mains can crap out or brown out, and the preamp won't have a problem. Whereas with a lot of regulated circuitry, there is going to be a cutoff point before the parachute fails.

JA: And then it fails catastrophically.

TdP: Yes. I prefer to build equipment that, if all else fails, will still limp. So if you're in a recording session and there's a glitch in the mains, at least the recording will still go through okay. I don't want to be downed because of that one problem. The same way a lot of people are going back to cars with simple, mechanical engine management systems rather than the modern mega-electronic management systems because there are less things to go wrong. As a result, they're more likely to be able to limp home [when things go wrong]. And if an electronic management system fails while you're [passing], for example, you're a dead duck.

It is better to have a system that is less prone, long-term, to problems—but it has to be designed correctly to cope with the short-term problems. Regulation is only a device used by conventional circuits because they conventionally are too sensitive to their power supplies. I try to design the beast to be relatively immune to the supply. Now one of my tube-amp competitors puts regulators willy-nilly everywhere. But some of those regulators are actually noisier than the prime regulator they have at the beginning of the supply. So they have achieved nothing. It is just a sales argument: "We have 10,000 regulators in this product; it must be better." "More" is not necessarily "better." That is my argument. That's the whole point.

JA: I understand your G88 preamp also doesn't use any capacitors in the RIAA EQ.

TdP: I'm using inductors to generate the RIAA network, passively. There is no feedback. The reason is that all capacitors have different sonic signatures, which has been written about ad nauseam by many people over the last 10 years. An inductor is wound with copper wire and is easy to wind at consistent linearity that allows me to get away from the problems of voltage distortion that capacitors have. It allows me to produce a low-impedance network to keep the noise floor of the preamp down. It allows me to generate a good accuracy beyond the two ends of the audio band. And it also allows me to provide a preamp with a good overload margin at high frequencies so the clicks and spikes of the records do not overload and do not intermodulate.

Provided it's done correctly and shielded correctly, you don't have any hum problems. The inductors are used in a balanced configuration, but I'm not going to go into all the intimacies of how it's achieved. That's still proprietary. But I am formally stating that I am the first to do it.

JA: Do you use a transformer for the moving-coil input?

TdP: Yes, I still use a transformer. I'm using what is in fact the HEAD sans packaging in the preamp. [A transformer] is still the most efficient way of converting one high-grade signal to another level. I'm also using balanced topology all the way through the preamp so the phono amplifier ends up with a balanced output transformer.

JA: Do you have favorite tubes for each application? There appear to be two factions in the US. They appear to go for either the 6DJ8 or the 12AX7 and their derivatives.

TdP: I don't have any particular favorite tubes. I use both. It's horses for courses. But the 6DJ8 never should have been used as an audio tube. It was originally designed by Mullard as a television front-end tube. It was designed as an RF amplifier and an RF oscillator to operate at 200MHz. It's a frame-grid tube, consequently it was never designed to have low mechanical noise, it should never have been used for audio. Because of the fact that it was used in televisions to operate on the 90V supply, it is a high-current triode by comparison to the 12AX7. But it's only fit to do service in certain parts of the audio circuitry. It should not be used carte blanche all the way through. I use it in my preamp, but only in the high-level balanced sections since it does a good job of driving the transformer.

JA: One tube you never see is the EF86 pentode (footnote 5). I only ever recall seeing it in the front end of the Radford ST25 power amp.

TdP: The EF86 is a very good tube for preamps. It's an incredibly linear tube. It has the gain, it has low microphony, it doesn't need DC filaments to make it work quietly, because it was designed to operate with a center-tap 6V filament. In those days [1951], DC filaments were prohibitively expensive, because of the cost of low-voltage, high-current rectifiers. It was designed for low-level microphone or photomultiplier amplifiers, projector sound and so on. So it had to have all these requirements designed in, it had to have a mechanical construction that minimized microphony. Quite the opposite of the 6DJ8, which was designed to do a certain job of work a different way.
I would use [the EF86] but for the fact that it is only produced in one country now. All the original Mullard stock is effectively finished, so from a production point of view it is not a viable tube to use. The problem was that people weren't using the EF86 in the '60s because they'd gone to transistors. Mullard didn't really see the need to keep it in production because it was only service-replacement volume, which was minuscule since tubes tend to have a life of the order of 100,000 hours. Power tubes have lifespans in the thousand hours or low thousands, whereas some of the small-signal tubes can have lives quite easily in the hundreds of thousands of hours—people don't realize that tubes can very nearly equate with transistors as far as longevity is concerned. I would love to use it. But the reality is that if you're going to produce more than one piece of equipment, forget it. It was a beautiful tube but unfortunately the uncertainty of buying it precludes it in modern-day manufacture.

JA: When you designed the Luxman 3045 in the '70s, you used an exotic NEC pentode wired as a triode. A 1990 tube designer, however, is pretty much forced into using the commonly available tubes.

TdP: You can always produce a one-off product with whatever you wish. You can produce a one-off using Western Electric 300Bs but you can't produce it in volume. Unless you use something that you know you can buy in five or ten years' time, it is really foolhardy to try to tread that path.

JA: This being the beginning of the '90s, will we still be playing LPs at the beginning of the next century?

TdP: I hope so.

JA: Do you think there will still be plenty of tube-amp manufacturers around?

TdP: Yes. We haven't seen the end of tubes yet. I mean, they were developing quite miniature tubes in the late 1960s for hearing aids, and the British Aircraft Corporation in England used micro-miniature tubes in their early missiles. It's just that when transistor technology came along, tubes got pushed to one side. In fact, a re-analysis of the tube is happening in computers. They're developing chips with cold-cathode tubes.

JA: Each chip carries many little microtubes, each about 20µm [half a thou'] across...

TdP: ...which operate on very low voltages. It can only get better. If we had devoted as much attention to tubes in the last 15 years as has been devoted to semiconductors, I think tubes would have been in a much more interesting state today.
________________________________________

Footnote 1: Now married to a Japanese wife, Oliva, Tim is one of the few Western engineers to have been employed in a creative role by a Japanese company. The classic Lux 3045 tube power amplifier is a TdP design, as were the monstrous M6000 and M4000 power amplifiers, two of the first Japanese transistor muscle amps.

Footnote 2: In the "Almost All-Tube Issue," Vol.7 No.3, May 1984.

Footnote 3: About three years ago, John Dent decided to take the gamble and go it alone. He and his partner, Island's second cutting engineer, hocked their houses, rented a premise in Camden, and called their cutting studio The Exchange.

Footnote 4: EAR's audiophile products are distributed in the US by EAR USA, Inc., 1087 East Ridgewood Street, Long Beach, CA 90807. Tel: (562) 422-4747. Web: www.ear-usa.com

Footnote 5: My 1966 edition of the Allied Electronics Data Book lists the 6267 as the US equivalent.
Read more at https://www.stereophile.com/content/tim-de-paravicini-dialing-original-experience-page-2#LQ7J9AUClkVPAF6K.99



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PostSubject: Re: The Outer Limits of Analog Audio   Fri Oct 05, 2018 12:09 pm


The Resolution of Analog Tape

Sonic has heard that people have estimated the “sampling rate” or the resolution of analog tape (compared to digital). Of course we are not doing an apples-to-apples comparison but it is interesting nonetheless.

I been looking around for what the estimate might be and Sonic finally found it!

From Positive Feedback Online Issue 68 (July/August 2013):

Mike Spitz owner of ATR Services and ATR Magnetics says, "Analog's attraction lies in its ultra-high resolution capability, DSD is capable of 2,822,400 transitions per track per second, but a high-quality mastering tape contains approximately 80 million transitions per track second. And that's just for 1/4-inch two-track tape running at 15 IPS, the resolution goes up substantially with wider tracks and higher tape speeds."

Sources:


https://positive-feedback.com/Issue68/dsd_pcm.htm

http://variety.com/2011/more/news/analog-recording-makes-a-comeback-1118029668/

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PostSubject: Re: The Outer Limits of Analog Audio   

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