Hoffman DRRI Conversion Low Volume - Magic Amp!

Started back on the DRRI today, hooked up the scope to the 8 ohm dummy
load, hooked up the Fluke to it also. Flipped on the power, after a
few minutes, flipped on the standby, got a moving ac volts of between
2.5 vac and 4.5 vac with volume knob on and no input signal. Volume
know off had 0 vac output. Turned volume know on channel 1 to 10 and
messed with the tone knobs and got some variation in output voltage.
Then I left channel 1 on and messed with the vol and tone knobs on
channel 2 and got additional output signal. Channel 2 had about half
the output of channel 1.
Then, I tuned in the scope and noticed that I had an increase in
output when I moved my hand over the chassis over the V1 and V2 area.
I was going for the volume knobs. I also got an increase in output
voltage. Then I started chopsticking stuff and got the same thing!
Finally, I found that thc closer to the end of the board, the more
output I got. And I touched the shielded cable from the jacks to V1
and got a full 13.5 vac output! ...
What gives? I also chopsticked the tubes and the EH in V1 showed
some static on the scope but all the rest were fine...now I am
wondering what is wrong...
.

Relevant Pages

  • Re: Hoffman DRRI Conversion Low Volume - Magic Amp!
    ... know off had 0 vac output. ... messed with the tone knobs and got some variation in output voltage. ... Then I left channel 1 on and messed with the vol and tone knobs on ... If moving your hands over the board causes changes, ...
    (alt.guitar.amps)
  • Re: Opinions on Oscilloscopes
    ... a new Chineses scope is the way I'm leaning. ... I hear what you're saying about the 2 channel. ... good triggering is all about ANALOG, ...
    (sci.electronics.equipment)
  • Re: Q about DSO (Instek GDS-2102)
    ... Which states that GDS-2102 which claims a 1 GS/s Real Time Sampling ... has only a 100MSa/s per channel on a two channel scope this ... IMHO when the sampling rate is at least ten times the fundamental ...
    (sci.electronics.equipment)
  • Re: How to convert differential signal to signle-ended signal?
    ... there is only one channel on our high frequency oscillascope. ... Otherwise a balun or a 180 degree combiner ... The best way is to use a two channel scope to monitor and then use the math function to "subtract" the two, therby having the scope perform the differential to single ended convesion. ...
    (sci.electronics.design)
  • Re: Oscilloscope, How TO?
    ... id> Don't isolate the scope from AC power ground. ... Most 2 channel scopes have channel ... non-inverting connects to the probe. ...
    (sci.electronics.repair)