Have mine (Outboard) set for my Ampex ATR-102 on order. Delivery is only a few weeks away. Really looking forward to them. Jeff has been great.
Tom
Tom
New Repro cards!
- Thread starter Bruce B
- Start date
Got my NextGen Studer A80 Repro Cards installed and clocking hours on them. Very impressed with them so far and Jeff was easy to work with making sure I got what I needed.
The only gear I had to compare against were the original Studer cards and a pair of SEPEA Playback Amplifier with output transformer cards which included Burson Opamps.
The NextGen cards easily beat both above to my ears so delighted with the purchase.
Now whether to consider the Doshi output stage at some point ??
The only gear I had to compare against were the original Studer cards and a pair of SEPEA Playback Amplifier with output transformer cards which included Burson Opamps.
The NextGen cards easily beat both above to my ears so delighted with the purchase.
Now whether to consider the Doshi output stage at some point ??
I received my outboard cards/frame from Jeff a couple weeks ago for use with my Ampex ATR-102. Since Jeff lives not too far from me, he came up to do the install and measurements and we did quite a lot of listening. The outboard frame is really nice- the cards just plug in, and there are very high quality (low noise) LED VU meters as well as switches for tape speed (I have 15/30 ips) and to turn the VU Meters off. I do not do any recording, at least right now, but the chassis has slots for Record cards if I want them in the future. We experimented with the rear panel "Standard" balanced outputs as well as the actual front of card outputs in balanced or single ended mode (depending on which cable adaptor we plugged it). As others have found here, the front panel outputs provided noticeable greater transparency as there is less buffering. Jeff did a little tweaking to match my Ampex metal heads and the measured frequency response was ruler flat up to 20K! (+ or - less than 0.5db in most cases; all well less than 1 db except at head bump which was only slightly higher). Most importantly, the sonics knocked my socks off! Mind blowing low level detail revealed never before heard spatial cues and hall/venue information. The cards are extremely low noise which aids of course in revealing the low level and micro-detail. Exceptional, true "studio recorder" dynamic range- wow! Above all, very "musical", non sterile. I am very happy! Jeff is a pleasure to work with and brilliant in what he does.
Attachments
-
IMG_2240.jpeg
Good question! I have special "bypass cards" that replace the Ampex audio boards and are wired out to XLR connectors with low capacitance wire. They are just non-active PC boards that match the Ampex edge connectors. The advantage is that I can plug the original cards back in should I need to. Also, as the Ampex head stacks can be swapped in mere seconds, this still retains the ability to use any head stack without direct wiring to the heads. (Theoretically, one can wire to the head stack connector, but that's much more finicky than this elegant bypass card solution). The only downside is that the pigtails from the bypass cards exit through a partially-open front door on the deck. (Some day I need to drill a hole in the bottom plate). I got these cards from the then ATR Services who made them for me when I originally had my ATR refurbished.
Understood, thank you.
You don't need to drill holes - as you know, there is a door in the bottom that can be kept slightly ajar - by just using longer screws.
I respect those machines so much I would rather not drill.
You don't need to drill holes - as you know, there is a door in the bottom that can be kept slightly ajar - by just using longer screws.
I respect those machines so much I would rather not drill.
Duh! Yes, I am aware of the door but never thought about using longer screws. Thanks for the suggestion! (And yes, I agree about preferring not to drill, which is why my cables have been hanging out the front for years!Understood, thank you.
You don't need to drill holes - as you know, there is a door in the bottom that can be kept slightly ajar - by just using longer screws.
I respect those machines so much I would rather not drill.
Lucky you! I should have bought a 2nd when I had the chance at a great deal years ago.I have that special love for those machines, I have three of them and working on another one now.
I agree with @Foxbat that the ATR is my favorite machine. In addition to (IMO) the best stock sonics of any pro machine available, you cannot beat the flexibility of the platform - swap formats in under a minute, 4-speed capability, 14" reel handling, mono to 4-track capability, etc.
With the ability to mount 2 repro heads in the block, it's a great opportunity to simultaneously be able to run stock and outboard playback electronics to do real-time comparisons between the inboard and outboard PB electronics. You may find that you prefer one over the other for certain material.
Last edited:
I also agree that on careful review of its published audio schematics for record and repro, I would expect the ATR in stock form to offer the best audio quality of any of the stock professional machines, including the various models from Studer, AEG Telefunken, Nagra, and the others I have examined, and this does seem to hold up in practice (listening);
However, this performance is unquestionably limited in comparison to the the best audio designs and implementations available today, and this conclusion is backed up indisputably by both a range of information-theoretic comparison measurements as well as listening to the same deck transport using its stock electronics versus the best available audio electronics electronics (plug-in or outboard).
And the good news is this: there is unquestionably a lot more information to be retrieved off good or very good masters and real-time copies than most listeners realize.
jeff polan
NextgenAudioSystems
However, this performance is unquestionably limited in comparison to the the best audio designs and implementations available today, and this conclusion is backed up indisputably by both a range of information-theoretic comparison measurements as well as listening to the same deck transport using its stock electronics versus the best available audio electronics electronics (plug-in or outboard).
And the good news is this: there is unquestionably a lot more information to be retrieved off good or very good masters and real-time copies than most listeners realize.
jeff polan
NextgenAudioSystems
Jeff, have you heard the Sony 5002/3 series? I find them superb. I had both ATR and the Sony and each was excellent in different ways. ATR more analog and rich and the Sony more detailed without being scientific sounding. But my Sony's have been gone through top to bottom and customized so I no longer have stock Sony's. But even stock they were very good.
Jonathan:
I have not heard the Sony APR 5002/3 series in conditions familiar enough to me that I could make a fair assessment of its sound, or direct comparison on the same source material against different decks; I also have NOT had the opportunity to make any technical measurements of the kind I usually take on analog decks these days (i.e. Impulse Response from complex cross-spectrum, Group Delay, Coherence function, along with THD/IMD at various fluxivities, etc.). But I certainly can offer comment on its audio design as reflected in the Sony 5000 series service manual.
Th design is fairly typical of its era, relying heavily on microprocessor-based digital control of most all audio parameters/settings using M-DACs (Multiplying Dacs) and CMOS switches/multipexers in conjunction with multiple NE5532 and NE5524 (decompensated 5532) op-amps for all analog gain and filtering functions, along with some polar electrolytic DC interstage coupling capacitors and a few TL072s and TL080s for good measure.
A number of things stand out. Starting with repro side:
The NE 5532 and decompensated NE 5534 are miserable sounding op amps by virtue of their high open loop gain (100dB or more) in conjunction with their low first-order open-loop compensation pole (100 Hz) and class AB outputs; while perhaps of adequate low noise floor this is a well-known recipe for slew-induced (TIM) distortion on fast transients that contain significant energy above 100 Hz pole. (Note that this kind of distortion is NOT measured by steady-state sinewave THD and IMD measurements). And they require lots of feedback to control steady-state THD and IMD because of their low stage operating currents and Class AB outputs used to minimize power consumption - but this exacerbates the SID/TIM issue. This conundrum is at the heart of the op-amp issue.
The main point is that op-amp based designs such as this - while cheap and easy to implement - have far excess open loop gain than what would be required to implement properly nearly any audio function required if they "simply" had more linear design and output stages, combined with insufficient open loop bandwidth for that same audio function. (By way of contrast, each of the NextGen all-discrete amplifier stages - highly linear with fully class A outputs - have 70dB open loop gain and a 50Khz first-order open-loop compensation pole - well above any possible audio frequency content and thus eliminating SID/TIM; this amounts to 158 Mhz unity-gain-BW product versus 10 Mhz unity-gain -BW product of the 5523/5534.) Such op-amp designs are routinely given a bad name for their sound. And the SONY repro preamp stage includes an LM394 low-noise differential input stage, non-cascoded for poor linearity, ahead of the 5534 that adds yet another 22dB of extra very wideband gain to the 5534 inputs which exacerbates the SID/TIM generated even further.
The design around the DG212 cmos bidirectional switches in the audio path is better than I have seen on some decks in terms of providing for something approaching linear operation (they at least approach working into a virtual ground) but are far from what is possible; SONY do a bit better with their M-DACs.
I could go on about various record side design issues, transformer inputs/outputs versus transformerless, and many other considerations. But the bottom line is this:
As was the case of many professional analog magnetic tape decks of the era, the manufacturers, designers and marketers became enamored (if not entranced) by the apparent power and capability, flexibility, and ease of use of new microprocessor controlled decks, enhanced by the push for synchronization with video and other services. Audio quality started to take a back seat to flexibility and convenience, as the digital engineers assumed increasing control in defining new deck features and capabilities; and for these same digital engineers and manufacturers, op-amps were the obvious cheap and easy design-in for audio; managers probably also expected that based on the standard specifications quoted of professional tape decks, all the major competitors had largely achieved audio parity: the features that were going to sell decks going forward were more about digital than audio.
In my view, the ATR features a superior selection of op amps in stock form, but it safe to say that none of these profesional decks from this past era can stand up to what can be done today in an all-out purist audio design based on properly designed discrete amplifier stages, correct time domain response, extended low distortion dynamic range, and without the prior op-amp circuitry compromises and digital control baggage.
Jeff
I have not heard the Sony APR 5002/3 series in conditions familiar enough to me that I could make a fair assessment of its sound, or direct comparison on the same source material against different decks; I also have NOT had the opportunity to make any technical measurements of the kind I usually take on analog decks these days (i.e. Impulse Response from complex cross-spectrum, Group Delay, Coherence function, along with THD/IMD at various fluxivities, etc.). But I certainly can offer comment on its audio design as reflected in the Sony 5000 series service manual.
Th design is fairly typical of its era, relying heavily on microprocessor-based digital control of most all audio parameters/settings using M-DACs (Multiplying Dacs) and CMOS switches/multipexers in conjunction with multiple NE5532 and NE5524 (decompensated 5532) op-amps for all analog gain and filtering functions, along with some polar electrolytic DC interstage coupling capacitors and a few TL072s and TL080s for good measure.
A number of things stand out. Starting with repro side:
The NE 5532 and decompensated NE 5534 are miserable sounding op amps by virtue of their high open loop gain (100dB or more) in conjunction with their low first-order open-loop compensation pole (100 Hz) and class AB outputs; while perhaps of adequate low noise floor this is a well-known recipe for slew-induced (TIM) distortion on fast transients that contain significant energy above 100 Hz pole. (Note that this kind of distortion is NOT measured by steady-state sinewave THD and IMD measurements). And they require lots of feedback to control steady-state THD and IMD because of their low stage operating currents and Class AB outputs used to minimize power consumption - but this exacerbates the SID/TIM issue. This conundrum is at the heart of the op-amp issue.
The main point is that op-amp based designs such as this - while cheap and easy to implement - have far excess open loop gain than what would be required to implement properly nearly any audio function required if they "simply" had more linear design and output stages, combined with insufficient open loop bandwidth for that same audio function. (By way of contrast, each of the NextGen all-discrete amplifier stages - highly linear with fully class A outputs - have 70dB open loop gain and a 50Khz first-order open-loop compensation pole - well above any possible audio frequency content and thus eliminating SID/TIM; this amounts to 158 Mhz unity-gain-BW product versus 10 Mhz unity-gain -BW product of the 5523/5534.) Such op-amp designs are routinely given a bad name for their sound. And the SONY repro preamp stage includes an LM394 low-noise differential input stage, non-cascoded for poor linearity, ahead of the 5534 that adds yet another 22dB of extra very wideband gain to the 5534 inputs which exacerbates the SID/TIM generated even further.
The design around the DG212 cmos bidirectional switches in the audio path is better than I have seen on some decks in terms of providing for something approaching linear operation (they at least approach working into a virtual ground) but are far from what is possible; SONY do a bit better with their M-DACs.
I could go on about various record side design issues, transformer inputs/outputs versus transformerless, and many other considerations. But the bottom line is this:
As was the case of many professional analog magnetic tape decks of the era, the manufacturers, designers and marketers became enamored (if not entranced) by the apparent power and capability, flexibility, and ease of use of new microprocessor controlled decks, enhanced by the push for synchronization with video and other services. Audio quality started to take a back seat to flexibility and convenience, as the digital engineers assumed increasing control in defining new deck features and capabilities; and for these same digital engineers and manufacturers, op-amps were the obvious cheap and easy design-in for audio; managers probably also expected that based on the standard specifications quoted of professional tape decks, all the major competitors had largely achieved audio parity: the features that were going to sell decks going forward were more about digital than audio.
In my view, the ATR features a superior selection of op amps in stock form, but it safe to say that none of these profesional decks from this past era can stand up to what can be done today in an all-out purist audio design based on properly designed discrete amplifier stages, correct time domain response, extended low distortion dynamic range, and without the prior op-amp circuitry compromises and digital control baggage.
Jeff
Thanks so much Jeff. I guess this is why my tech completely strips the Sony's down to bare bones to replace the faulty parts and components. My Sony's are all custom. Including all power supply components removed to an external enclosure. The ATR is a fabulous machine indeed. I loved mine. Just too heavy for me to move about. I so appreciate you taking the time to go into detail about all of this. And yes, none of the machines can match modern electronics although on the record side the Stellamaster was darn close.
I have a stellamaster as well and I agree with you. All discrete transistor amplifier modules-making my point once again versus opamp designs (but with class AB output stage that can be simply upgraded to class A by adding a 8-10mA current sink pull down (2n5459 Idss 8-10 mA ) on the SOC outputs (even potted modules) at the similar expense of battery power consumption (meaningless today with external power supply or LI battery pack); a design marred only by remaining high quality bipolar electrolytic DC Blocking coupling caps in the signal path and residual motor pickup at 3x the capstan rotation frequency. (I have a fix for that- a canceller- as well.) An amazing machine in many ways, way advanced for its time, unsurpassed for remote work with the ABR, and a great example of when less is more.
Jeff
Jeff
In terms of sound there is another contender - the Crown. Purely in terms of sound, mind you... as moving the belt by hand to change the speed is not exactly high-tech. It definitely has good voice, though.
That and the Ampex are the among the very few machines that are listenable in their stock form.
It definitely has good voice, though.That and the Ampex are the among the very few machines that are listenable in their stock form.
Nice. Have you compared it with the Ampex 102? What is the model of your Crown? Thanks.In terms of sound there is another contender - the Crown. Purely in terms of sound, mind you... as moving the belt by hand to change the speed is not exactly high-tech.
That and the Ampex are the among the very few machines that are listenable in their stock form.
I have Crown 822 where Chuck Ziska added the 15ips IEC EQ position, and it is very good. Hard to tell which one is better, with some machines you know right away, here I would need to do more comparisons. Some people liked it better. It is not a modern machine, though, its tape handling is far from ideal. And even no tape counter on mine. So when I use it I do slow wind on some other machine.
So when I use it I do slow wind on some other machine.Similar threads
 | Steve Williams Site Founder | Site Owner | Administrator |  | Ron Resnick Site Co-Owner | Administrator |  | Julian (The Fixer) Website Build | Marketing Managersing |