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Topics - traf

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Tape Tech / STUDER A80RC recording issue
« on: February 01, 2010, 10:15:16 AM »
Hello techs,

Here is the issue: The ready/safe switched turn the green lights on (on the meter bridge) but when I press rec/play, the rec and play buttons light, but the red lights (on the meter bridge) do not turn on. I her the input signal when pressing input, but the tape remains unrecorded and unerased (both channels).

I replaced the record amps - same result.

I cannot replace the oscillator as I don't have a second one. The oscillator card's leds do not light up and I do not hear any click from the rec/oscillator relays. The oscillator pcb is quite warm after a few minutes of work, mostly around the heat sinked devise.

Any tips?

regards

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Tape Tech / Butterfly heads on Revox PR99: also replacing the erase head?
« on: December 26, 2009, 03:50:16 AM »
Hello,
I replaced the original 2mm rec/repro heads with butterfly (0.75mm, these were produced by Studer for A67 but they told me I can used them on PR99). It seems I must replace also the erase head (with the full track type, for mono), according to the Studer head catalogue (occasionally I hear remains of undeleted material from 4tr tapes, seemingly between the 2 trks). Is that correct? Should I just replace or are there any adjustments of the erase function (I recall of a jumper somewhere, used to increase erasing power/voltage)?

Another issue that may be head related: When I biased for SM900, I could not use the 10kHz/-10dB overbias method as the peak was never surpassed (bias current at max and still no drop of recored signal). What could that be?

Thank you and happy holidays,
Tod


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Tape Tech / 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

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