duesentrieb":2cbiudue said:
Check/follow the "default" switching circuit with the beep function of your DMM, Steve. In default mode (amp off, no voltage supplied to relays) at least one channel should work, also try first to uninstall the VTL(s). Just lift one of their non-LED-legs - you may get bleeding, but a better impression of whats going on inside - and VTLs can be "nasty", you know . . .
Good luck.
Hi Olaf,
I had to fix the mains switch as I had the indicator lamp wired to the wrong terminals. It was on all the time when the amp was plugged in. I just found this out because I did not have an indicator lamp until it showed up yesterday... (forgot to order one...)
I have now followed the default switching path from the input through each of the relays to the controls and I have "beep" continuity as expected (Loop off). Good...
I then tested the amp with my guitar again and was very careful this time. The "plex" gain control adjust gain from clean to distorted plexi type gain as I said. The "plex" master now does adjust the volume, but not how I'd expect. Even with the master turned all the way down, there is still a good amount of sound, but no where near as loud as when it is cranked. Not working right, but signal is getting there. Tone controls still don't seem to do anything, but I notice now that adjusting the density control reduces the volume of the amp. The amp is still not loud as a cranked plexi, but it is reasonably loud in the room. Lets put it this way, after a few minutes my wife asked me to turn it down (she thinks it sounds good though. HA!), but the one time she heard my PeaceMaker fully cranked because I had left my attenuator up full from when she wasn't in the house, she was completely freaked out!
Thin, trebly sound with distortion - no bottom end or mids... does sound kinda cool though...
As I said before, I re-wired the manual switches because I misunderstood how they worked. Now, no matter how I switch them, I don't get the hum I was getting with them before in some settings. Good...
One strange thing is now I'm only measuring 5.9VDC on the preamp heaters... I was getting ~ 6.2VDC before... haven't changed anything in that circuit?? Hmmm.....
Measured all the voltages now again and here is where I'm at:
V1 (12AX7) - Pin 1 - 128.2, Pin 3 - .796, Pin 6 - 175.7, Pin 8 - 1.351
V2 (12AX7) - Pin 1 - 134.2, Pin 3 - .824, Pin 6 - 235, Pin 7 - 134.2, Pin 8 - 134.7
V3 (12AX7) - Pin 1 - 266.2, Pin 2 - 17.79, Pin 3 - 45.96, Pin 6 - 175.8, Pin 7 - 0, Pin 8 - 1.369 (Loop tube)
V4 (12AX7) - Pin 1 - 198.3, Pin 2 - 20.77, Pin 3 - 32.82, Pin 6 - 194.3, Pin 7 - 21.85, Pin 8 - 32.9 (Phase inverter)
V5 (EL34) - Pin 1 - 35.6 mV, Pin 2 - 3.261, Pin 3 - 459.7, Pin 4 - 458, Pin 5 - -40, Pin 6 - 459.7, Pin 7 - 3.445, Pin 8 - 35.6 mV
V6 (EL34) - Pin 1 - 33.7 mV, Pin 2 - 3.282, Pin 3 - 460, Pin 4 - 457.5, Pin 5 - -40, Pin 6 - 459., Pin 7 - 3.474, Pin 8 - 33.7 mV
V7 (EL34) - Pin 1 - 37.9 mV, Pin 2 - 3.307, Pin 3 - 460.2, Pin 4 - 457.5, Pin 5 - -40, Pin 6 - 458.8, Pin 7 - 3.521, Pin 8 - 37.9 mV
V8 (EL34) - Pin 1 - 38 mV, Pin 2 - 3.393, Pin 3 - 460.2, Pin 4 - 457.5, Pin 5 - -40, Pin 6 - 458.8, Pin 7 - 3.584, Pin 8 - 38 mV
Lotsa stuff look suspect in the preamp section...
Power section and PI look relatively correct, but the voltages are all down a bit across the board since my last measurement... I didn't change anything... wonder if this could be from fluctuation in the wall voltage I'm getting.... I dunno...
I'll try the VTL... Wonder why the "plex" master sems to adjust the volume, but not all the way off.... Since I'm getting continuity across the default path I can't figure out why the tone stack controls don't work... All the grounding looks good and I measure 0 volts where I should with the amp on...
Lots more to do...
Steve
