Do different tape transports sound different?

Fred Thal

[Industry Expert]
Jul 15, 2016
161
11
123
This is a question I've been hearing for over 45 years. It still makes me smile.

Answering authoritatively necessitates a listening demonstration where all other variables have been removed.

For the comparison of the two recorder-reproducers shown (Ampex ATR-102 and Studer A820), we put in identical half-inch repro heads and cables and connected them to identical playback circuitry.
ATR  A820 comparison - Copy.jpg
 

DonH50

Member Sponsor & WBF Technical Expert
Jun 22, 2010
3,947
306
1,670
Monument, CO
I would expect they would sound different... Different transports will have different vibrations, wow and flutter, variations in tape path, etc. that will cause changes in the sound. I suppose it's possible the differences on a couple of excellent transports might be inaudible but they'd certainly be measurable.

IMO - Don
 

Fred Thal

[Industry Expert]
Jul 15, 2016
161
11
123
A meaningful evaluation of different tape playback electronics requires first that the electronics are each carefully aligned to the calibration tones found on the master tape used for the playback comparison.

A comprehensive set of alignment tones recorded to the master tape is a hallmark of any professionally made analog recording. Correspondingly, any true tape recording professional would regard playback electronics that will not accurately align to the standard equalization curves as merely sadly misguided consumer toys. (Imagine the chaos of comparing phono stages that do not accurately follow the RIAA curve.)

Some people assume that the differences between different tape playback electronics will be much more readily audible than would be any differences between different transports. However the reverse is true.
DSC_0504 - Copy.jpg
 

RogerD

VIP/Donor
May 23, 2010
3,734
318
565
BiggestLittleCity
Hello Fred,

Theoretically no,but probably yes.
 

Fred Thal

[Industry Expert]
Jul 15, 2016
161
11
123
Some of us are just not satisfied with relying solely on subjective evaluations about audio gear. We also want meaningful, accurate, repeatable measurements too.

When it comes to measurements on tape transports, we are basically looking for unwanted amplitude and frequency modulation. And we cannot rely on the old, weighted-band flutter measurement standards that were based on faulty assumptions about the ear's sensitivity. We need to look more broadly across the entire audio band.

An engineer working for the US professional tape machine manufacturer 3M must be credited with first calling attention to the need to accurately characterize the audible differences of tape transports. He also argued against the accepted belief of the time that scrape flutter was inaudible in music program. His name is Dale Manquen. He later worked for Ampex.

Manquen developed an instrument that allows one to both see on a meter and hear over a loudspeaker or headphones, the grunge (the unwanted AM and FM distortion) that is added to the audio signal by a tape transport. Those of us who have worked on tape transport design owe a great debt of gratitude to Dale Manquen.

Now, a few words about the pictures of Ampexes I have posted and some personal disclosure. Visitors to my company Audio Transfer Laboratory, sometimes express surprise that we have Ampex ATR-102s on prominent display. Especially when they know that the parent company (Adolph Thal Audio Engineering) is founded largely on borrowed Studer tape machine design engineering.

The answer is that the Ampex ATR-102 was hands-down the most popular tape machine employed by the US-based record labels in the late 1970s through the 1980s. So, keeping our two ATR's in top operating condition gives us some immediate street cred with many surviving recording engineers from back in the day. Further, it affords us a very familiar starting point for demonstrating to those people what we believe is the clear superiority of our modern, Studer transport based ATAE reproducers.
 

Ron Resnick

Site Co-Owner, Administrator
Jan 24, 2015
16,017
13,347
2,665
Beverly Hills, CA
Thank you, Fred, for starting this very interesting thread!
 

Fred Thal

[Industry Expert]
Jul 15, 2016
161
11
123
Anyone with a grasp of the physics underlying audio recording and reproduction appreciates that preserving time base accuracy is fundamentally important. From recent study of hearing sensitivity in the era of digital audio, we have discovered that our sensitivity to time base variation or disturbance is astonishingly acute.

Back on topic. There are many types of analog tape transports. Now, if you venture out to go looking at those transports, armed with specialized instrumentation to find out how various transports are distorting the time base accuracy and adding unwanted amplitude modulation where the tape passes over the sound heads, you might soon find yourself in a quagmire. At that point, you'll understand the need to classify and sort the many transport architectures by type.

Eventually, your study will bring you to the precision guidance, servo constant tension, servo capstan transport. It will sound the best and it will measure the best.

To my knowledge, the first such commercial design appeared forty-seven years ago, in 1969. The machine was the Studer A80. Upon first hearing it in Europe, highly experienced, critical listeners reported a whole new level of clarity and focus to recorded sound. This was almost entirely due to the A80's superior time base accuracy (from the servo constant tension and the servo capstan). Even when fitted with its compromised, three-head (confidence recording) headblock, it clearly had audibly lower scrape flutter (from the precision guidance transport architecture).

Alas, a hugely unfortunate detail of precision guidance transports is that they cost fifteen to twenty times more to manufacture than other transport architectures. (This explains the far more commonly seen surviving Studer models like B67, A810, A807 and all the others which were not precision guidance transport designs and produced in enormous quantities.) While the Ampex ATR-102 was indeed servo constant tension and servo capstan, it too was not a precision guidance transport.

Of the few other makers of precision guidance machines, AEG in Germany was perhaps the most notable one. Yet Studer remains widely acknowledged as having been the leader, successfully producing two families of this class, the A80 and the A820.

Here's a side note. Sixteen years ago (in 2000), broadcaster organizations here in the USA and Canada were giving away Studer A80s. Literally. I was incredulous upon learning this. I saw it as an under-appreciation stemming from extreme ignorance. Today, I'm happy to see that the appreciation of this legendary product has improved.

But another unfortunate detail is that the surviving Studer A80 and A820 machines have absolutely not aged well. Perhaps ninety-nine percent of all A80s and A820s still in service today are badly under-performing, mainly due to transport mechanical issues, such as faulty bearings (most commonly dried out lubricants) and improper reconditioning attempts, including extreme high precision motors that have been ruined by unqualified "re-building".

My alarming assertions presented here can be backed-up, not just by ear, but also by playing back specialized test tapes with instrumentation connected.

I suspect that the movement of a 45-year-old Rolex might possibly still be in near first class condition today, if the original crystal is intact and the watch case back has never been opened outside the factory. But people have always been quite free to go inside Studer tape machines. Sadly, too often doing harm.

Yet, for those who recognized an A80 or A820 machine and saved it from the scrap yard, they may be rewarded today for preserving some finely-crafted hardware components that can comprise a very solid foundation for building a spectacular new tape machine.

That is, if they have the talent and budget for doing so.

This is what we are doing at ATAE in 2017.

An investor believing in our mission (or even just a couple of supporters placing pre-orders) is wanted!

Also, the very last, fully stock and fully original Studer A820 recorder-reproducer (reconditioned by us) that we will offer is now on eBay. To call it very special is perhaps an understatement. Price is $44,300.

Please reach me thru the ataudioeng.com website.

Thanks for reading everyone.
 

astrotoy

VIP/Donor
May 24, 2010
1,547
1,017
1,715
SF Bay Area
I have a different perspective on the ATR-102's with and without external prepros. I have two. One has a Doshi 3.0 prepro and the other is stock. Side by side, playing 1/2" tapes, the Doshi is clearly superior. I don't have the ATR Aria electronics to compare with the Doshi. Also don't have one of Fred's fantastic redone Studers, only making the comparison between my two ATR-102's.

Larry
 

squasher

Well-Known Member
Apr 7, 2016
53
23
138
Alas, a hugely unfortunate detail of precision guidance transports is that they cost fifteen to twenty times more to manufacture than other transport architectures. (This explains the far more commonly seen surviving Studer models like B67, A810, A807 and all the others which were not precision guidance transport designs and produced in enormous quantities.)

Hi Fred,

Just so we're all on the same page, can you define what you mean as a precision guidance transport?

Specifically, why is the A80 in this category but the A807 is not?

I have no reason to doubt your statements, I'm just looking for more education on the differences in this area. As an aside, I am the proud owner of an A80 I bought from ATAE but also own an A807 I bought independently.
 

NorthStar

Member
Feb 8, 2011
24,305
1,323
435
Vancouver Island, B.C. Canada
The Studer A820, and its tape tension arm.





https://reverb.com/ca/item/3434840-studer-a820-master-recorder

•• http://goldengaterecording.com/id60.html
 

microstrip

VIP/Donor
May 30, 2010
20,806
4,698
2,790
Portugal
(...) Manquen developed an instrument that allows one to both see on a meter and hear over a loudspeaker or headphones, the grunge (the unwanted AM and FM distortion) that is added to the audio signal by a tape transport. Those of us who have worked on tape transport design owe a great debt of gratitude to Dale Manquen.
(...)

The Fred Thal posts have great information about this interesting subject. We can find the referred work and instrument developed by Dale Manquen in this site: http://www.manquen.net/audio/index.php?page=1 (Full site : http://www.manquen.net/manquendotnet/audio/)

The Altair Tape and Transport Diagnostic System is shown in the picture. According to the site "The system provides independent AM and FM measurements in the passbands of .5 Hz-250 Hz (mechanical components only), 250 Hz-5 kHz (scrape components only), and .5 Hz-5 kHz (all components combined). A weighting filter is included for conventional NAB and IEC weighted flutter measurements. Residual measurement noise for the widest bandwidth is typically .005%RMS for FM and .1% for AM, which is approximately 20 dB below the best transport and tape tested to date."

It is a fantastic all analog instrument. There is information enough in the paper to develop a virtual instrument using a high quality soundcard - it should be a great Labview project for students!
 

Attachments

  • a1.jpg
    a1.jpg
    8.1 KB · Views: 443

Fred Thal

[Industry Expert]
Jul 15, 2016
161
11
123
Hi Fred, can you define what you mean as a precision guidance transport?

Hi, is this Chris K?

Anyway, the term comes from the field of web guidance, an obscure segment of mechanical engineering that deals with continuous web processes seen in manufacturing plants like textiles, light gauge sheet steel and paper mills. Many old-time newspaper printing plants also employed continuous web (offset) printing, where a roll of paper perhaps thousands of feet long runs through the presses (or transits through the web) only to be cut into pages at the very end, after all the printing is performed.

For the mechanical engineer who is designing continuous web processing equipment, making it all work without wrinkles (in the literal sense here) is hardly trivial. A fundamental principle in this discipline is that there can be but a single plane of reference for the alignment of all of the rolling elements in the system. This reference plane must be invariable and immensely stable. And each and every one of the rolling elements then needs to be rigidly fixed to that plane absolutely normal. (That means with perfect perpendicularity.) Perfectly perpendicular, not to the degree, not to some minutes of the degree. But down to seconds of the degree.

In terms of tape transport guidance types, we basically see only two: those of forced guidance and those of precision guidance.

Do they force the tape to follow a path that is defined by the placement of (typically edge) guides? This is forced guidance and it is seen in over 99.9 percent of all tape machines.

Or, is the tape free to follow its own natural path through the web system, with no forced guidance at all? This is precision guidance. It is seen mainly on the better one and two-inch multichannel tape machines.

Attend an operator training class someday at ATL / ATAE and you'll see all this possibly better explained with some tape transport hardware examples that we pass around the classroom. We might first show you an Ampex AG-440 transport foundation casting (a TFC, or "a top plate", in the old Ampex California factory jargon) that was once used in a very popular, force-guided, commercial machine.

Then maybe we'll show you the equivalent part from an Ampex ATR-102. Often at that point, participants examining the ATR 100 part will say "Oh, much, much better. Much more stable and precise!"

Then we'll pass around the TFC from a Studer A80.

And we hear quiet gasps. Or, OH MY GOD!

Lastly to come out is the TFC from an A820.

I won't disclose the reaction that part gets. But if you happen to know much about manufacturing, you'll immediately recognize that it isn't fiction that Studer precision guidance transports cost way over fifteen times what it cost to build an entire Ampex.

Jay McKnight (of Ampex and MRL) has a very good paper on web guidance in tape machines. I'm not sure it is presently linked from his MRL site. You may ask Jay about it on the Studer list.
 
  • Like
Reactions: dwhistance

squasher

Well-Known Member
Apr 7, 2016
53
23
138
Thanks for the lengthy and informative explanation, Fred. In reading your various posts, I have often wondered exactly what you meant by this term.

Hi, is this Chris K?

Nothing slips past you, does it? :)
 
Jan 18, 2012
2,323
2,410
1,475
Drobak Norway
very interesting
when you discuss TFC differences, are you referring to the cast bracing of the chassis for motors,, brakes, solenoids, headblocks etc?
so I guess its all about "torsional stiffness" then? through bracing and mass?
best
Leif
 

Fred Thal

[Industry Expert]
Jul 15, 2016
161
11
123
are you referring to the cast bracing of the chassis for motors,, brakes, solenoids, headblocks etc?
so I guess its all about "torsional stiffness" then? through bracing and mass?
best
Leif
Correct.
 
Jan 18, 2012
2,323
2,410
1,475
Drobak Norway
I' ve had Tascam 52. Otari 5050.Revox PR99. Studer B67. A807.A810. Lyrec Frida and they all seen pretty Mickey Mouse and flimsy compared to the A80. Torsional rigidity is a must to anchor the power inherent in such a powerful machine imo
Best
Leif
 

Mike Lavigne

Member Sponsor & WBF Founding Member
Apr 25, 2010
12,471
11,367
4,410
I've owned a number of (very nice) RTR decks over time, but only my 2 Studer A-820's remain.

Fred speaks about the precision guidance transport. I think I hear what that does compared to other decks I've had. but for a non-techie like myself what floored me was seeing the structure under the top cover plates of the A820's. it's a massive one piece aluminum casting that all the mechanicals are attached to and worth seeing with your own eyes should you get the chance. no rolled metal or bolted together sheet frame. never seen anything like it related to any audio product other than a few small rack shelf products milled out of solid billet. imagine a product as big (as a washing machine) as the A820 milled out of a solid billet.

precision is no accident.

I can't say how the A80 relates to this but likely something similar.
 

RogerD

VIP/Donor
May 23, 2010
3,734
318
565
BiggestLittleCity
The Fred Thal posts have great information about this interesting subject. We can find the referred work and instrument developed by Dale Manquen in this site: http://www.manquen.net/audio/index.php?page=1 (Full site : http://www.manquen.net/manquendotnet/audio/)

The Altair Tape and Transport Diagnostic System is shown in the picture. According to the site "The system provides independent AM and FM measurements in the passbands of .5 Hz-250 Hz (mechanical components only), 250 Hz-5 kHz (scrape components only), and .5 Hz-5 kHz (all components combined). A weighting filter is included for conventional NAB and IEC weighted flutter measurements. Residual measurement noise for the widest bandwidth is typically .005%RMS for FM and .1% for AM, which is approximately 20 dB below the best transport and tape tested to date."

It is a fantastic all analog instrument. There is information enough in the paper to develop a virtual instrument using a high quality soundcard - it should be a great Labview project for students!

Thanks for posting.

Fred,

Since most of these tape preamps are now 30 years or older,have you upgraded these and if so is the transport noise (distortion) still the most significant aspect of audible performance?
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing