I've got a Musical Fidelity X-P100 preamp on the bench. This is basically the first series Nu-Vista preamp with the nuvistas replaced by some sort of FET. Everything else (including the PCBs) is the same.
Now this one has been Hot-Rodded. Big time. All the audio caps have been replaced by much fancier ones; the larger transistors have been given bolts-as-heatsinks and there's a range of additional, deleted and replaced components here and there. The digital stuff seems unmolested (but I have no remote so can't test).
Naturally, it's not working: the mute really is doing it's thing (tick), the audio makes it through the input selector, volume control and primary pre-amp stage (tick, tick, tick) but then is lost somewhere in the morass of extra transistors hidden under the power supply board (which sits on top of the main PCB). I'm presuming they form some sort of output buffer. (There's also the phono stage stashed under the power supply board - I'm ignoring it for the moment.)
Clearly, someone somewhere put some effort into understanding the circuit and why various bits should be upgraded, replaced or removed. But I can't find even a stock schematic, nevermind a thread in a forum outlining hot to Hot Rod this thing. And, unlike a Ducati, there's no Haynes manual I can order.
Anyone got any ideas or leads?
Thanks!
Now this one has been Hot-Rodded. Big time. All the audio caps have been replaced by much fancier ones; the larger transistors have been given bolts-as-heatsinks and there's a range of additional, deleted and replaced components here and there. The digital stuff seems unmolested (but I have no remote so can't test).
Naturally, it's not working: the mute really is doing it's thing (tick), the audio makes it through the input selector, volume control and primary pre-amp stage (tick, tick, tick) but then is lost somewhere in the morass of extra transistors hidden under the power supply board (which sits on top of the main PCB). I'm presuming they form some sort of output buffer. (There's also the phono stage stashed under the power supply board - I'm ignoring it for the moment.)
Clearly, someone somewhere put some effort into understanding the circuit and why various bits should be upgraded, replaced or removed. But I can't find even a stock schematic, nevermind a thread in a forum outlining hot to Hot Rod this thing. And, unlike a Ducati, there's no Haynes manual I can order.
Anyone got any ideas or leads?
Thanks!