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Author Topic: Advanced modification of Studer A80RC  (Read 8100 times)

Offline traf

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Advanced modification of Studer A80RC
« on: December 23, 2009, 02:59:28 PM »
Hello reelers,

I noticed that some of you are quite experienced/interested with the Studer machines. Hence I hope this could be the start of a lively exchange on how to upgrade an A80 to achieve best possible performance, going as far as one can.

Here is my 10 step plan:

1. Replace all electrolytics with Panasonic FM and alike;
2. Replace all electrolytics on the audio boards with Nichichon Muse, bypassed by styrene caps;
3. Replace all other caps on the audio boards with Silvermica and/or pp or mkp
4. Replace the audio path resistors with TKD;
5. Replace the in/out transformers with better ones (???)
6. Rewire audio links with silver/teflon;
7. Add a power supply with Rcore trafo and superregulators to power the audio boards (12V);
8. Replace PS diodes with fast recovery;
9. Replace audio path transistors (BC550) with 2SC1815L/2SA1015L (I spent a lot of time to find the Toshiba L version, in vain - any ideas?)
10. Add JFR extended range heads.

Please share your views and experiences, any specific suggestions/comments will be appreciated. I will keep you informed about the progress/results. Recently I did a similar job with a PR99, with great results.

I have a similar plan for the A810, but will first only recap, and possibly copy the EPROMs, as it seems a more sophisticated beast to mess-up with.

Best wishes,
Tod

Offline Teeg

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Re: Advanced modification of Studer A80RC
« Reply #1 on: December 24, 2009, 11:59:27 AM »
 Hmmmm, seems like quite a bit of work for a project which may not result in any more/better performance. Replacing caps in the PS is probably worth the effort, but playing with the rest of the passive components may not be.

  Perhaps the Studer gurus on the forum will have a different opinion; I own an 80VU but it just arrived a few days ago, no mods planned except for heads and tube playback electronics.

Tj
T.j. Bassi  
    Martin Logan reQuests....Martin Logan Descent x 2....Atma-Sphere MA1 OTL amplification....Krell KPS25s digital front end....VPI Scoutmaster....Studer A80 VU MKII....Ampex 300-2 Tube/SS Playback "Ampexius Maximus"....Ampex MR-70

Offline ironbut

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Re: Advanced modification of Studer A80RC
« Reply #2 on: December 24, 2009, 12:22:31 PM »
I love your enthusiasm Tod but I can only pass on the advice that Fred Thal offered me on his Studer list years ago. To paraphrase it, he said that " the Studer master recorders (the A80 being one of) are systems that work as a whole and many of the parts are chosen for a reason".
With that in mind, I'd be careful how you go about doing these modifications and upgrades. From what I could tell, Fred spends a lot of time "undoing" modifications that were done just to bring machines back up to factory spec.
The A80 probably lends itself to these kinds of upgrades more than the more modern Studers but I'd certainly be sure that the machine's up to factory spec before trying to improve it.
steve koto
 Sony scd 777es(R. Kern mods)> Vpi Aires>Dynavector XX-2mkll>Bent mu>CAT ultimate>CJ premeir 140>Magnepan 1.6qr(Jensen xover)Headphone Eddie Current Zana Deux>AT ad2000,HD800 ,Metric Halo ULN-2 (battery powered),
 HE Audio Jades

Offline Teeg

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Re: Advanced modification of Studer A80RC
« Reply #3 on: December 24, 2009, 01:53:43 PM »
 Is the Studer list still active? I've tried to sign up quite a few times and have not been approved.

Tj
T.j. Bassi  
    Martin Logan reQuests....Martin Logan Descent x 2....Atma-Sphere MA1 OTL amplification....Krell KPS25s digital front end....VPI Scoutmaster....Studer A80 VU MKII....Ampex 300-2 Tube/SS Playback "Ampexius Maximus"....Ampex MR-70

Offline Ki Choi

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Re: Advanced modification of Studer A80RC
« Reply #4 on: December 24, 2009, 02:31:03 PM »
Hi Tj:

Try http://tech.groups.yahoo.com/group/STUDER/?yguid=356657641

Also, if you look under the "file" section on the left, you will see all the old Studer List archived posts.

Happy Holidays!

Ki
Ki Choi

Offline ironbut

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Re: Advanced modification of Studer A80RC
« Reply #5 on: December 24, 2009, 02:59:17 PM »
Thank Ki, I'll be sure and put that link in the "Reel to Reel links" sticky.

Unfortunately Tj, it was dropped about a year or so ago (Nov.2008 to be exact).

If you have specific questions, you may want to pose them on the Ampex list since a few of the Studer list regulars frequent that listserve.
 
I was lucky enough to have subscribed to the list for a couple of years before it's demise and followed many discussions on what component was best suited for for this or that position. Not owning a Studer myself, I never saved any of those discussions (it didn't however, keep me from asking some obvious audiophile type questions which brought the wrath of God  down on me, which is ok as long as someone gave me a straight answer).






steve koto
 Sony scd 777es(R. Kern mods)> Vpi Aires>Dynavector XX-2mkll>Bent mu>CAT ultimate>CJ premeir 140>Magnepan 1.6qr(Jensen xover)Headphone Eddie Current Zana Deux>AT ad2000,HD800 ,Metric Halo ULN-2 (battery powered),
 HE Audio Jades

Offline traf

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Re: Advanced modification of Studer A80RC
« Reply #6 on: December 25, 2009, 01:21:59 AM »
Thank you for the replies. I agree that every component is there for a reason and therefore my intention is to do the mod with caution and consultation. On the other hand, those components are 30 years old. This means that some had degraded (caps mostly) while others have better performing modern analogues (e.g. transistors, resistors, caps, transformers, even wires) that Studer would have used if they were available/affordable at the time. Furthermore, the best studios that used those master recorders have all modified them one way or another, as Mark Levinson did with the then famous ML-5 Studer (I was unable to find details of the mod though).

I like the A80 over all other beasts because it is mod/service friendly, and discrete in its electronics (hence my A810 mod will be more limited/conservative)

As I listed, the mods may look extensive, but they just replace old components with same value of better ones. I used the same approach with my PR99 and it now performs well above specs (freq responce and S/N) + has more years of life.

I do not rule out the option of having an external repro unit and using only the transport, but this seems less cost-effective approach to me.
Merry Christmas

Offline Teeg

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Re: Advanced modification of Studer A80RC
« Reply #7 on: December 25, 2009, 11:26:29 AM »
  Ki-  Thanks for the link; just joined. Cant wait to get some time in on the new machine later this week.

Tj

 
T.j. Bassi  
    Martin Logan reQuests....Martin Logan Descent x 2....Atma-Sphere MA1 OTL amplification....Krell KPS25s digital front end....VPI Scoutmaster....Studer A80 VU MKII....Ampex 300-2 Tube/SS Playback "Ampexius Maximus"....Ampex MR-70

Offline High and Outside

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Re: Advanced modification of Studer A80RC
« Reply #8 on: December 26, 2009, 04:50:00 PM »
Hi Todor, and welcome to the forum.

My short answer: there are three areas that define the sound of a tape machine: the transport, the heads and the electronics. The transport has the largest influence of the three. The Studer A80 is one of the best transports. An A80 in good running condition is a joy. Studer heads are also excellent.

The Studer electronics are generally not to my taste, at least anything they made in the solid state era. The A80 was made in several versions over time. The transports were basically similar, and any version is good. They differed quite a bit in their electronics. Luckily you have the version that has the reputation for having the best sound.

I see nothing wrong with upgrading the passive components, meaning the capacitors and resistors, with better ones if you proceed slowly, confirm that you haven't changed the performance of the machine, and listen to be sure you like the direction the sonics are going. Don't assume that parts are better just because someone on the internet said so. I have been down that road, and found for instance that some parts that were "audiophile approved" contributed to an etched and dry presentation. If you are doing this to make it sound better, you must use your ears to confirm that you're going in the right direction.

I would leave the transistors alone. The general trend over time has been for transistors to get worse, not better. You might be able to improve upon them, but only if you have serious expertise in this field.

And the transformers, well I would only replace those if you are really sure that you have something better. Most of what's easily available will not improve on the performance of what you already have.

Good luck, and report back if you make progress.
Paul Stubblebine
Managing Director, The TapeProject

Offline traf

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Re: Advanced modification of Studer A80RC
« Reply #9 on: January 11, 2010, 09:01:44 AM »
Just recapped the electrolytics on the PS and most control boards. I intend to use low ESR replacements (Oscon) for most tantal caps. Is that a good idea? (one of the control PCBs is a newer version and has only EL caps, no tantals, in contrast to the older version pcb)

I reconsidered the idea of replacing the audio transformers. Instead I wonder if/how it is possible to take the output signal directly after the input stage on the repro pcb (leaving the higher level balanced trafo-based XLRs as well).