New Repro cards!

[canigo]

Add me to the list for a pair of A820 cards.

 

[stellavox]

We're working on it.

Looks to be two new cards - the preamp in the headblock and the "repro" card in the main audio chassis. Someone - like maybe us - will have to do the replacement on the preamp, the repro will hopefully be a "plug-n-play" with the EQ switch and the various adjustments on that card and a mini-XLR connector to "take off" the clearer audio to your system - either balanced or unbalanced.

Charles

 

[Foxbat]

Sounds great, guys... but the big question is - when are you gonna make similar set for Ampex ATR-102?

Victor

 

[srs148]

Sounds great, guys... but the big question is - when are you gonna make similar set for Ampex ATR-102?

Victor

There are currently no plans in the works, but that's something that could be done, especially if there's demand for it (though I personally love the stock ATR electronics compared to my Studer decks). Jeff is local to me in Southeastern PA, so I can provide an ATR as a development platform for him if he needs it.

 

[Foxbat]

Stock ATR electronics is indeed quite good, but, as we know, this hobby is not about some objective things.

It is all too common for high-end buyers to change things before even powering up their new acquisition. Although I must admit, the R2R machine users tend to be on the tame side... at least I don't see many here replacing their stock fuses with $10K each "special" ones.

What's wrong with you, people????

 

[christensenleif@msn.com]

So time to put my money where my mouth is;
New A80 repro boards on their way to Norway tomorrow

 

[Foxbat]

Kudos to you for supporting those nice guys doing great job!

 

[NextGen]

Based on a first examination of the Service Manual schematics and parts lists, the ATR Main Audio PWA and PADNET appears a good candidate for upgrade along the lines of our NexGen A80 repro card - the PWA card includes as well the record head driver, erase head driver, and sync input/output; I would plan to replace at least the record head driver as well by the same discrete direct coupled Class A amplifier stage we use now on the A80 NectGen Repro card, if space allows.

It would also be very nice to include a group-delay equalizer on record for greatly improved time domain response/reduction of linear distortion. (Our planned upcoming A80 record Card has both a group delay equalizer and 2-stage B-H linearizer that can add some 6-8 dB dynamic range depending on tape at 15 ips as tested on a Stellavox).

The PADNET is little more than a collection of jFET switches, trim pots, and option-setting switches for Record and Repro - thus I expect can be consolidated into a smaller footprint as well as better performance, so that perhaps a single new Main Audio board occupying the same combined PWA + PADNET footprint is feasible as a Plug-and-Play replacement, and the way to go. Else surface mount would seem necessary.

(Otherwise, I suppose we could consider eliminating the sync input and output capabilities to pick up space.)

Also, bypassing the input/output amplifier assembly to take inputs and outputs directly from the PWA/PADNET replacement would seem necessary for best possible sound; how this can be done (mounted XLR? mini breakout cable?) will be need sorted out given the mechanicals.

Beyond the stated specifications, I have no measurement data or reported measurements on this card set or the machine itself; nonetheless it looks like a competent design from the era, and looks (on paper) to make fewer adverse trade-offs, and thus better performing (and sounding) than the Studer A80 and A8XX electronics, mostly because of higher speed and faster settling op amp (LM318 vs NE5532), and fewer coupling (electrolytic) capacitors in the signal chain. However, there are still a few notable weaknesses that should be attacked.

Overall, I would expect performance improvements comparable to (or even greater if you include the Record side benefits) to what we have achieved with the NextGen A80 Repro Card; I hope to have access to an ATR 102 soon to dive in deeper.

ATR -100 users: please chime in if you have any thoughts on such an upgrade/replacement, important features not considered or experience, and your interest.

Jeff

 

[Foxbat]

My personal take on this would have emphasis on the recording side, as the playback is already well taken care of with external preamp, however, I would still consider the total solution, and here are some points.

Although the ATR-100 is already easily the best recorder out there, I have no doubt it can be made better, but one thing I would like to retain would be monitoring the recording level - ideally both on Input and Tape side. I presume that could be done while still using the high-grade local card output.

Also, it would be nice to have the direct playback head access.

As far as the connectors - a typical ATR-102 has empty slots next to the audio cards, that can be used for a connector panel. This would still be less, than ideal, as the cables would interfere with the cover, but would allow you to use full size XLR's for both inputs and outputs, instead of the less than common mini types.

 

[NextGen]

Thanks much for the valuable feedback.

It looks easy to retain the existing single-ended outputs and inputs to/from the line input/output assembly, as well as make these available separately with added connectors. New balanced line Inputs /outputs entirely independent of the exiting ones, transformerless, and free from any additional cabling/switching/pots/(Unbuffered) VU metering etc. (as in the case of our Nextgen A80 repro upgrade)is also Planned.

As u point out, the card cage door will probably need to be left open to access these additional outputs/inputs but Ideally with full size XLRs.

I like your idea of a “direct“ Repro head output, but prefer the (unequalized) Low noise preamplifier stage output (Rather than a direct head connection) to avoid any adverse Noise/RFI pickup impact at this most sensitive location; also if unbuffered by preamp stage Head damping and Subsequent EQ conformance could be adversely affected by the shielded cabling to output connector and subsequent external electronics).

If anyone else have Ideas or viewpoint on the ATR-100 please chime In.

jeff

 

[Foxbat]

Hi Jeff,

I understand your concern with providing an unbuffered PB head access, and in general sense your caution is appropriate. Still, I have a lot of experience with such direct connections (currently have several) and I found that in most cases that is not a problem, and any inaccuracies can easily be tuned out during the normal adjustment procedure.

So one option, perhaps worth considering, might be a couple of jumpers, allowing the user to either use, or bypass the buffer stage.

Victor

 

[srs148]

So time to put my money where my mouth is;
New A80 repro boards on their way to Norway tomorrow

Awesome, Leif! And you have Todor's MTSL cards already, correct? That being the case, it'll be great to hear your thoughts on the between the two.

 

[srs148]

@NextGen it looks like you may be picking up an ATR sooner than we imagined .

 

[Fred Thal]

Hello Charles and Jeff,

A reader of this forum contacted me saying that I needed to log in and read what you’re up to.

Wow. I see so many topics!

Can I begin by being pedantic, correcting a point of proper Studer machine identification?

Reading through your posts (Charles and Jeff), I see that everywhere you've written A80, you are in fact talking about the A80RC.

Investigate and you’ll discover that the R and RC’s B62-based audio circuitry is entirely different from a real A80. Different everywhere, all the way back to the head inductances!

The RC (Rundfunk kompakt, or compact) variant was a popular, lower-cost, broadcast market product that some insiders still refer to as the Reduced Cost, or Really Cheap, or Radio Canada model. The substitution of the venerable B62 audio circuitry was done as a cost savings measure.

So, in light of the above, if you care a bit about Studer product history, I suggest a simple fix: re-name your product the Nextgen A80R card.

Next topic I want to raise is prior art on A80R audio circuitry modifications.

Just in case you don’t know, here in the USA, one of the first A80R audio circuitry modifiers was NYC recording engineer David Hancock, who in the early to mid 1970s had (I believe) the first, half-inch, two-channel, 30 in/s A80Rs in the country. David recorded one of Harry Pearson’s all-time favorite (for sonics) classical LPs with that machine and also personally cut the lacquer master.

Then there was Crystal Recording in Los Angeles, whose Studer mods garnered some attention.

Yet perhaps best known was Mark Levinson and his A80 RC-based ML-5 master recorder system. I think this re-design was the most interesting and one you should study, especially if you intend to do record electronics.

Next topic: In-headblock repro head preamplifiers

As I recall it (from forty years ago) with the extremely low output of repro heads in the lowest octaves, most highly experienced tape machine electronics designers of the 1980s era found putting a repro head gain stage (which could be ideally tailored to any particular head) in the headblock a very smart approach.

Then, the advent and adoption of headblock identification invited the kind of sophisticated (and complex) recall automation possibilities seen for example in the Studer A820. It absolutely depends on that headblock circuit.

Next topic: Current flowing through the head

Wow, I jumped out of my chair on reading this, Jeff. I suspect that so few have ever given it a second thought. Yet it’s hugely important!

Think about a real master tape. And remember the tenet: First, do no harm! (That was an ATAE marketing campaign headline, from about fifteen years ago.) The unintended short-wavelength erasure of recorded audio tape is absolutely a real concern. Kudos to you for having it on your radar!

Somewhere in your posts, you mentioned the professional community. What I will tell you is that the public remains mostly unaware of how many irreplaceable original master tapes have been ruined and are still being ruined, to this very day. Playback on the wrong transports is the biggest cause. (“Oh, yes. The oxide very commonly falls off some of these old tapes when we play them. We did the best transfer that we could.”)

In my view, the professional community are people who don’t know that they don’t know.

Here’s an organization hoping to fix that: recordedmusicpreservation.org

Next topic: Replacement repro cards for Ampex ATR-102s, Studer A810s (and god knows what else)

Personally, I would vote that you instead take the approach of packaging your designs in the form most optimum to their performance. Forget these fifty-year-old recorder-reproducer confining and constricting audio card frames and power supplies. If it’s tape repro electronics that you want to optimize, then develop one that accommodates a wide range of repro head inductances and show us that your circuit aligns to the standard equalizations with spot-on accuracy.

After all, some have built phono preamps that match the RIAA curve everywhere to within a tenth of a dB. This is what the pro community acctually needs for tape. Then, maybe you’ll agree to sell us (ATAE) the raw boards, so we can put it in our product, the A80 Reproducer?

Thanks for reading.

Fred Thal

 

[NextGen]

Hello Charles and Jeff,

A reader of this forum contacted me saying that I needed to log in and read what you’re up to.

Wow. I see so many topics!

Can I begin by being pedantic, correcting a point of proper Studer machine identification?

Reading through your posts (Charles and Jeff), I see that everywhere you've written A80, you are in fact talking about the A80RC.

Investigate and you’ll discover that the R and RC’s B62-based audio circuitry is entirely different from a real A80. Different everywhere, all the way back to the head inductances!

The RC (Rundfunk kompakt, or compact) variant was a popular, lower-cost, broadcast market product that some insiders still refer to as the Reduced Cost, or Really Cheap, or Radio Canada model. The substitution of the venerable B62 audio circuitry was done as a cost savings measure.

So, in light of the above, if you care a bit about Studer product history, I suggest a simple fix: re-name your product the Nextgen A80R card.

Next topic I want to raise is prior art on A80R audio circuitry modifications.

Just in case you don’t know, here in the USA, one of the first A80R audio circuitry modifiers was NYC recording engineer David Hancock, who in the early to mid 1970s had (I believe) the first, half-inch, two-channel, 30 in/s A80Rs in the country. David recorded one of Harry Pearson’s all-time favorite (for sonics) classical LPs with that machine and also personally cut the lacquer master.

Then there was Crystal Recording in Los Angeles, whose Studer mods garnered some attention.

Yet perhaps best known was Mark Levinson and his A80 RC-based ML-5 master recorder system. I think this re-design was the most interesting and one you should study, especially if you intend to do record electronics.

Next topic: In-headblock repro head preamplifiers

As I recall it (from forty years ago) with the extremely low output of repro heads in the lowest octaves, most highly experienced tape machine electronics designers of the 1980s era found putting a repro head gain stage (which could be ideally tailored to any particular head) in the headblock a very smart approach.

Then, the advent and adoption of headblock identification invited the kind of sophisticated (and complex) recall automation possibilities seen for example in the Studer A820. It absolutely depends on that headblock circuit.

Next topic: Current flowing through the head

Wow, I jumped out of my chair on reading this, Jeff. I suspect that so few have ever given it a second thought. Yet it’s hugely important!

Think about a real master tape. And remember the tenet: First, do no harm! (That was an ATAE marketing campaign headline, from about fifteen years ago.) The unintended short-wavelength erasure of recorded audio tape is absolutely a real concern. Kudos to you for having it on your radar!

Somewhere in your posts, you mentioned the professional community. What I will tell you is that the public remains mostly unaware of how many irreplaceable original master tapes have been ruined and are still being ruined, to this very day. Playback on the wrong transports is the biggest cause. (“Oh, yes. The oxide very commonly falls off some of these old tapes when we play them. We did the best transfer that we could.”)

In my view, the professional community are people who don’t know that they don’t know.

Here’s an organization hoping to fix that: recordedmusicpreservation.org

Next topic: Replacement repro cards for Ampex ATR-102s, Studer A810s (and god knows what else)

Personally, I would vote that you instead take the approach of packaging your designs in the form most optimum to their performance. Forget these fifty-year-old recorder-reproducer confining and constricting audio card frames and power supplies. If it’s tape repro electronics that you want to optimize, then develop one that accommodates a wide range of repro head inductances and show us that your circuit aligns to the standard equalizations with spot-on accuracy.

After all, some have built phono preamps that match the RIAA curve everywhere to within a tenth of a dB. This is what the pro community acctually needs for tape. Then, maybe you’ll agree to sell us (ATAE) the raw boards, so we can put it in our product, the A80 Reproducer?

Thanks for reading.

Fred Thal

Thanks, Fred for a wealth of information.

First: On the identification of the various Studer models. Yes of course you are correct: we are talking about the "A80 Master Recorder", also referred to as A80 RC Mark I/Mark II in my Studer Service Manual. (The B62 also uses exactly the same Record, and Repro Cards and electronics, so that our NextGen Rero cards are likewise plug and play in the B62). Sorry for any confusion.

(The Studer A80 VU MKII/MKIII/MKIV and the A80 MR MKII, which use the same VU electronics, are not interchangeable or plug-and-play with our NextGen A80RC Repro Cards. I like your suggestion to call our cards A80RC or A80R.)

As to whether and to what extent the stock VU electronics were actually superior to the stock non-VU electronics, I have limited experience and no actual measurements on the VU, so I leave that to you; (on paper it looks like replacing the A101 discrete hybrid with NE5532 with class AB output may or may not be a plus, but still suffers from what we consider numerous deficiencies including multiple electrolytic capacitors in the signal path, the NE5532s themselves, the unfortunate (high-distortion) transistor Hi/LO speed EQ selection switching (carried over from the A80RC although with different transistors chosen), relatively high head input bias currents, among others.

We are also aware of the prior efforts including the ML-5; my partner in this endeavor Charles King ("Stellavox") has long been considered the go-to guy for repairs knowledge on the ML-5 electronics.

I am not at all against a headblock preamplifier, and in fact we are pursuing our current NextGen discrete preamp stage in surface mount for the A810/A820 series of decks, along with a new A810/A820 Repro Card; not so much for any expected improvement in A-wtd SNR by putting the preamp in the headblock but to gain real estate on the Repro Card. It certainly can't hurt unless we have to make tradeoffs in the preamp because of the small footprint in the headblock.

I agree with your main point: we should offer a product that can easily accommodate a wide variety of head characteristics, tape equipment, and equipment users, with spot-on EQ conformance, and outstanding performance characteristics; we believe we have achieved all the performance goals, but designing it into different form factors and interfaces are a challenge. In that regard we are pursuing design of a surface mount version of our discrete DC-coupled Class A operational amplifier stage which we can "drop-in" to various carrier boards as required, i.e. for preamp stages, EQ stages, record driver stages, etc.

The first of these is likely to target the Studer A810/820 series, and then the Ampex ATR-100 series.

Regards,
Jeff

 

[Foxbat]

I think there is room for both - the comfortably fitting internal boards, as well as the outboard boxes - those are two very different customer needs, as not everyone is going to want more boxes.

I still respectfully disagree on the headblock preamp... in my experience removing it from the signal chain produced a very large improvement. Of course I come from a slightly different world, as all my head preamps are all vacuum tube based, but personally, I would rather limit the possible customer base than stop short of best sound.

On parallels with RIAA world... truth be told, we simply don't know what is happening there. So yes, we adjust our RIAA networks to look perfect on Audio Precision, but the real world frequency response is totally unpredictable.

Being able to easily measure the tape FR is a mixed blessing - because it is doable with minimal hardware and skills investment we are fixated on it. But when was last time someone measured his turntable FR? Out of sight, out of mind - life becomes easier.

Like it or not, the ideal frequency response is no assurance of good sound. And conversely - a system with clearly imperfect one can produce captivating sound full of life.

Please note - I am not talking about studio environment, where absolute accuracy is so important, but the end user's system.

Victor

 

[christensenleif@msn.com]

this is one of those times you feel you´ve bought something really special
from the packing , the documentation and individual lab results, to the product itself
to say the least, the balanced buffered output already sounds spectacular right out of the box......
will stick to that for as long as I can hold myself before I switch to unbuffered balanced
thxs Charles and Jeff
best
Leif

 

[christensenleif@msn.com]

couldn´t hold myself any longer and compared with Mastertapesoundlab boards
Nextgen in std balanced is cleaner and more controlled with superb bass, but not as freesounding in the mid and HF region as Todors cards....they have more ambience and better decay with richer harmonics
HOWEVER
when hooking up to the unbuffered balanced output the game changes
the Nextgen boards are better on all parameters with intact bass reproduction AND the glorious mid /hf range
they´re also cleaner sounding, but not at any instance analytical or harsh sounding
tape was LSC-6177: Arthur Rubinstein plays Chopin Mazurkas NY, 1965

btw I run no active preamp, only a TVC where the signal sources drives the poweramps and had no problem with too little gain

 

[stellavox]

couldn´t hold myself any longer and compared with Mastertapesoundlab boards
Nextgen in std balanced is cleaner and more controlled with superb bass, but not as freesounding in the mid and HF region as Todors cards....they have more ambience and better decay with richer harmonics
HOWEVER
when hooking up to the unbuffered balanced output the game changes
the Nextgen boards are better on all parameters with intact bass reproduction AND the glorious mid /hf range
they´re also cleaner sounding, but not at any instance analytical or harsh sounding
tape was LSC-6177: Arthur Rubinstein plays Chopin Mazurkas NY, 1965

btw I run no active preamp, only a TVC where the signal sources drives the poweramps and had no problem with too little gain

WONDERFUL CHRISTENSEN!!

Glad your happy - we couldn't be more pleased.

Point of clarification - the hookup that got you the best sound from our boards comes from the UNBALANCED output via the RCA breakout cable - not the BALANCED XLR? Right? If so, it makes sense - it's the "cleaner path" - although I couldn't hear much difference in the few, limited, A/B listening situations I had.

Both outputs are available from the 4-pin mini-XLR jack on the front panel - just depends on how you wire them out - balanced or unbalanced.

ENJOY!

Charles

 

[christensenleif@msn.com]

WONDERFUL CHRISTENSEN!!

Glad your happy - we couldn't be more pleased.

Point of clarification - the hookup that got you the best sound from our boards comes from the UNBALANCED output via the RCA breakout cable - not the BALANCED XLR? Right?

Both outputs are available from the 4-pin mini-XLR jack on the front panel - just depends on how you wire them out - balanced or unbalanced.

ENJOY!

Charles

hi
haven´t tried the unbalanced hookup yet....will do
what´s status on the A80 record cards?
best
Leif