Bought a mint PR99 which has balanced XLR connections for studio and broadcast usage. Schematics learned it works with transformers. The input circuitry is straight forward, the xfrm is a 1 : 1 so if I just omit that I get an unbalanced RCA compatibe input. The output however (+4dB so way too high) is not so simple as the xfrm is part of the feedback loop of the driver amp and cannot simply be omitted. The PR however does have a "monitor out" connector which outputs the L and R signals before the line output and balancing stages. Seems way more attractive to use as it's unbalanced by nature and before a couple of opamp based linecards and transformers.
Do we have subject matter knowledge here? I can't find the specs for the monitor output and wonder the level is high enough for domestic line level..
Leonard
Do we have subject matter knowledge here? I can't find the specs for the monitor output and wonder the level is high enough for domestic line level..
Leonard
Simplest/cleanest is to use the monitor output as you've mentioned. You could take an unbalanced tap off the input to the output transformer thru a cap but that output section doesn't "sound" that good. Changing the IC might help. And if you want the best sound that deck can make; change all 6 coupling caps on the repro card. Watch out for the trimmers on any of those plug-in boards; the wipers have lost their tension and become intermittent by even looking at them.
Charles
Charles
reVox PR99
Hi Charles, thanks for the response, I figured, looking at the output amp diagrams, I would not need all these obscure electronics 🙂
I tried to figure out what effective output I can expect from the Monitor Output. I can't find any manual or internet article specifying it. Would you know? Hopefully it will be >500 mVeff so that I won't need to amplify it getting it up to normal line level..
leonard
Hi Charles, thanks for the response, I figured, looking at the output amp diagrams, I would not need all these obscure electronics 🙂
I tried to figure out what effective output I can expect from the Monitor Output. I can't find any manual or internet article specifying it. Would you know? Hopefully it will be >500 mVeff so that I won't need to amplify it getting it up to normal line level..
leonard
Progress?
Hi - just stumbled across this thread.
Did the <monitor output> win the day as a "line out" of sufficient quality / level without tweaking the innards?
Can the monitor connection be used for input (i.e. record) or just output / playback?
I'm about to connect my PR99 MK2 to my Naim NAC52 for record and playback so I'm looking for the right cable. It's either 4 x XLR (PR99) into 5-pin locking DIN (Naim) or 7-pin DIN (PR99 monitor) to 5-pin DIN (Naim) or some combination of both.
On my earlier (but now defunct) PR99 MK3 I had some XLR to phono cables that came with it but they were cheap and nasty, but worked.
The NAC52 preamp is looking for 75mV @ 100kΩ line input and it outputs 75mV @ 600Ω for record.
Any help in this area welcome.
Thanks.
Hi - just stumbled across this thread.
Did the <monitor output> win the day as a "line out" of sufficient quality / level without tweaking the innards?
Can the monitor connection be used for input (i.e. record) or just output / playback?
I'm about to connect my PR99 MK2 to my Naim NAC52 for record and playback so I'm looking for the right cable. It's either 4 x XLR (PR99) into 5-pin locking DIN (Naim) or 7-pin DIN (PR99 monitor) to 5-pin DIN (Naim) or some combination of both.
On my earlier (but now defunct) PR99 MK3 I had some XLR to phono cables that came with it but they were cheap and nasty, but worked.
The NAC52 preamp is looking for 75mV @ 100kΩ line input and it outputs 75mV @ 600Ω for record.
Any help in this area welcome.
Thanks.
On one of the B67's I recently received, I found tap points on the analog circuit board backplane which were originally used to feed the output attenuator before the output amp and balanced transformer (it was originally a remote console unit) and I was able to solder RCA output jacks directly to that point.
The audio is fine quality wise here (at least to circuits of the time) - it is even DC decoupled - however the level is a bit on the low side. I don't know how closely what Studer did on the B67 correlates to the PR99, though.
I haven't yet tried to do the equivalent on the record side, but will, unless I convert to tubes first.
The audio is fine quality wise here (at least to circuits of the time) - it is even DC decoupled - however the level is a bit on the low side. I don't know how closely what Studer did on the B67 correlates to the PR99, though.
I haven't yet tried to do the equivalent on the record side, but will, unless I convert to tubes first.
Last edited:
- Status
- Not open for further replies.