You don't see these every day...

Bruce B

WBF Founding Member, Pro Audio Production Member
Apr 25, 2010
7,006
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Snohomish, WA
www.pugetsoundstudios.com
believe that one used to be owned by Peter McGrath, or at least he recorded on it.
 

MylesBAstor

Well-Known Member
Apr 20, 2010
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New York City

Ki Choi

Member Sponsor
May 13, 2010
764
29
1,590
Seattle WA area
That's perhaps one deck that Ki doesn't have :)

The deck belongs to Fred Thal. He's been trying to find a buyer for few years.

As you might be aware already, it is a Studer A80RC MkII with improved audio power supply card and redesigned record and repro cards. Considering it shares the same designer, its audio performance should be similar to the Cello tape preamp. If it wasn't for one special opamp part that is a mistery, I would have attempted at building the card based on schematics I have. Chales King had acquired the ML5 cards in a card cage and have it running with a Revox machine.

Ok Myles, Maybe in few more years...
 

MylesBAstor

Well-Known Member
Apr 20, 2010
11,236
81
1,725
New York City
Thanks for the interesting info Ki!!!
 

jdza

Well-Known Member
May 3, 2010
294
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1,513
I have changed one of my A80Rs into an ML 5 using cards and advice from Fred Thal. The changes are basically the record/repro cards,modified oscillator card,output module and power supply ( The cards run at +/- 15V DC as opposed to the Studer cards at +/- 12 VDC).John French did his usual superb job in rebuilding the headblock to ML5 spec. This uses Studer Schmetterling heads and a mono erase head.I am very proud of my number 1 machine which is a totally rebuilt A80R with FM mastering heads but the ML5 rebuilt (number 3,number 2 is an A80R with highly modified Bottlehead Eros) is really a significant step up even if it does not measure as well as the Studer/FM. Other idiosyncrasies are the single ended outputs and the operating level of 200nW = -6db.
 

stellavox

Well-Known Member
Apr 23, 2010
284
61
1,583
My ML 4.5 - work in progress

Here's a pic of my recently completed, what I call my ML-4.5, from an ex-Levinson engineer's trove of stuff. More info later:

http://web.me.com/reeltapes/Home_of_Reeltapes/Stellavox_Levinson_ML5.html#3

Rich brought a few of his Basie tapes over (in Hollywood 1961) over and we made some very successful
dubs - after also running them through the Palette to take out some unbearable brightness.


Charles
 

jdza

Well-Known Member
May 3, 2010
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Initially I used my machine with the 12V Studer psu cards. It sounded lovely. When I went to the 15V supply I used an offboard 20V transformer to get the regulated 15 V DC needed. The sound became excruciatingly bright. The culprit turned out to be the wiring arrangement between the transformer and the card cage.





 
Last edited:

Ki Choi

Member Sponsor
May 13, 2010
764
29
1,590
Seattle WA area
I have changed one of my A80Rs into an ML 5 using cards and advice from Fred Thal. The changes are basically the record/repro cards,modified oscillator card,output module and power supply ( The cards run at +/- 15V DC as opposed to the Studer cards at +/- 12 VDC).John French did his usual superb job in rebuilding the headblock to ML5 spec. This uses Studer Schmetterling heads and a mono erase head.I am very proud of my number 1 machine which is a totally rebuilt A80R with FM mastering heads but the ML5 rebuilt (number 3,number 2 is an A80R with highly modified Bottlehead Eros) is really a significant step up even if it does not measure as well as the Studer/FM. Other idiosyncrasies are the single ended outputs and the operating level of 200nW = -6db.

Did you buy the ML5 cards from Fred?
From your post at the bottom, you mentioned you had also upgraded audio power supply to an externally regulated +/- 15VDC on your Machine with Flux Magnetic heads (machine 1 ?). So, you were supplying the original Studer audio cards with +/- 15VDC and let the cards regulate them down to +/- 12VDC. Am I correct?
If you have your normal operating level set with 200nW/m MRL cal tape at 1Khz, it would only be down -2dB from +4dBm normal operating level set with 250nW/m tape ...your -6dB seems bit too low...
 

jdza

Well-Known Member
May 3, 2010
294
255
1,513
Did you buy the ML5 cards from Fred?
From your post at the bottom, you mentioned you had also upgraded audio power supply to an externally regulated +/- 15VDC on your Machine with Flux Magnetic heads (machine 1 ?). So, you were supplying the original Studer audio cards with +/- 15VDC and let the cards regulate them down to +/- 12VDC. Am I correct?
If you have your normal operating level set with 200nW/m MRL cal tape at 1Khz, it would only be down -2dB from +4dBm normal operating level set with 250nW/m tape ...your -6dB seems bit too low...

Ki

This from the ML 5 manual: Operating level : Defined as 200 nanowebers per meter equals -6dbm. The way I understand this is that my MRL 250nw test tape then be -4 dbm instead ?

Yes the cards came from Fred

I am not quite with you re the power supply. My Studers use a stock supply providing +/- 16V to the regulator card that then sends +/- 12v to the audio cards. . However the ML 5 cards operate at +/- 15 V regulated. My tech felt that regulating 16V to 15V is too close and therefore opted for an outboard +/- 20 V transformer AC to be regulated to+/- 15V DC. We had hum issues though so opted for a DC supply to the regulator card .
 

Ki Choi

Member Sponsor
May 13, 2010
764
29
1,590
Seattle WA area
Glad the ML5 cards went to a good home. I was tempted to buy them few months back but held out (for a change).

Sorry to have you confused regarding the normal operation level issue. If you run the 250nW/M MRL test tape at 15 ips for 0VU reading on your VU meter, you should be outputting 1.25V at the output and running at +4dBm.

Acutally Studer A80RC has just transformer two secondary windings of 15VAC taps going into a simple +/- 12VDC audio power suppy regulator card. From the photos, the ML5 has a beefy audio power regulator card and a separate power supply unit with may be with higher voltage DC supplies. Charles should know more since he has them.
 

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