By chance I have found exactly the aforementioned preamplifier manufactured by NRG Control, namely the PA-1. It is really impressing, literally everything is controlled by relays, not only the input / output switching but also each minuscule volume and balance step. The preamp is thus packed with relays and related chips that control them. The phono preamplifier also looks spectacular, yet I've not checked whether it's for MM or MC nor what the included dip switches are for. I have added two pics from the inside, please excuse for their poor quality, they were made on the fly, I'll add better ones later.
The preamp has two issues: The first one is that the remote control board seems to be missing, there are only some loose wires (e.g. for the motor of the volume "pot" / sensor) left. That's a pity, but given that the remote function obviously came as an option, I can easily live without it.
The other thing (that may be related though) is that the record output only works on one channel, regardless the chosen source. Furthermore, the regular output is normally playing on both channels unless the rec out and input switch are at the same position. In that case, the same channel is missing on both the rec out and the normal output. The guy who supposedly removed the remote board has tied some of the loose wires together, and I wonder if that triggers one of the relays so that one rec out channel is permanently switched to ground (muted).
Although this is easy to circumvent—the PA-1 has a defeat position for the rec out switch where each input is are sent to the output(s) without a problem—I would like to solve this issue, but the real problem is that this preamp seems to be extremely rare: So far I have found absolutely no information about it, not even specs and of course much less so the schematics or a service manual.
Now my hope is that someone here might know more about the brand, the preamp in particular or a source for some helpful insights that might lead to a solution for the problem. In any case, thanks in advance for whatever you might be able to share!
Thomas
