Revox PR99 mods
Jed Leland
Posts: 183
Hello,
I thought I'd show some of the projects i completed last year. This is a Revox PR99 MK1 that I have overhauled and modified. You can think of the PR99 as the professional version of the famous A77. It was produced with both 7.5ips and 15ips and is a two track record and playback. It was in pretty good shape, but I was able to completely take it apart and do a "frame-up" re-build. I found new replacement 1/4" phone jacks for headphones and mics. I also bought a brand new replacement capstan motor, new control knobs. I thoroughly cleaned and polished all of metal parts before putting back together. Revox has an extremely detailed service manual that comes in a red three ring binder, showing exactly how everything works.
as for the modifications, itself, I replaced all of the coupling caps with Black Gates and every playback resistor with .1% bulk foil "naked" resistors from Vishay. To me, the combination of coupling caps and Vishay resistors eliminates that grainy grungy quality that the original has.
I took the industrial looking back cabinet and had it powder coated a nice blue to, sort of, update the appearance and painted the upper section of the front plate to get rid of some deep scratches it had. I modified the way the playback circuit path is designed, eliminating the sections that i didn't feel were necessary. My goal is to route the signal path through as few a parts as possible. Taking the audio output from the monitor connection instead of the balanced output is a big step.
Cheers, Jed
I thought I'd show some of the projects i completed last year. This is a Revox PR99 MK1 that I have overhauled and modified. You can think of the PR99 as the professional version of the famous A77. It was produced with both 7.5ips and 15ips and is a two track record and playback. It was in pretty good shape, but I was able to completely take it apart and do a "frame-up" re-build. I found new replacement 1/4" phone jacks for headphones and mics. I also bought a brand new replacement capstan motor, new control knobs. I thoroughly cleaned and polished all of metal parts before putting back together. Revox has an extremely detailed service manual that comes in a red three ring binder, showing exactly how everything works.
as for the modifications, itself, I replaced all of the coupling caps with Black Gates and every playback resistor with .1% bulk foil "naked" resistors from Vishay. To me, the combination of coupling caps and Vishay resistors eliminates that grainy grungy quality that the original has.
I took the industrial looking back cabinet and had it powder coated a nice blue to, sort of, update the appearance and painted the upper section of the front plate to get rid of some deep scratches it had. I modified the way the playback circuit path is designed, eliminating the sections that i didn't feel were necessary. My goal is to route the signal path through as few a parts as possible. Taking the audio output from the monitor connection instead of the balanced output is a big step.
Cheers, Jed
Post edited by Jed Leland on
Comments
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That's quiet a project and nice job so far. I like the blue powder coat and are you going to do the rest to match?
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Thanks, Jake,
I believe I'm pretty well finished with the PR99, there are a few small nicks on the side rack rails, but unless I find some in better shape I'll leave them alone. The next related project is a Revox PR99 playback deck that i found on eBay in really excellent shape. The goal is to set it up so it will play the Tape Project tapes at 15ips and be able to play the NAB tapes at 7.5ips. The Tape Project tapes are real time copies of master stereo tapes with the European playback EQ. Regular two track tapes from RCA and Mercury, for example, would play back at NAB EQ. This would be a great way to have a machine play both tape formats. The Tape Project tapes are unbelievable sounding!
In these photos you can see what the front of the deck looks like. I've removed the reel tables and the control knobs. The other photo shows the rear of the deck with the plug-in circuit boards, making this a great deck to work on. The last shot shows the playback circuit board and a box of Vishay resistors and my bag of Black Gate caps.
Cheers, Jed
