The new 8 Ohm dummy load arrived and that's a "load" off my mind! (..sorry, couldn't resist! ack, there I go again)
Anway, "soundmasterg" has been so kind as to instruct me on another method of measuring the output of the Solarus without interference from the pre-amp and tone stack stages. First, I've run a Sine wave (150 mV) directly from a signal generator firstly into: the front jack (for reference), then the signal was applied to the Triode grid of the 7199 (with the Pentode section separated) large enough to drive the output section to it's clean signal maximum and finally the signal directly applied to the Pentode grid with the Triode re-connected and the output section driven to it's clean signal maximum. It took/takes a bit larger voltage to drive the output section when applying a signal directly to the cathode so an HP model 200 Audio Oscillator was used.
I've included images of the measurements taken with a scope-meter that displays 2 channels, both set for VAC (RMS) and DC. The output from the amplifier is displayed on Channel "A" (top left) of the meter in all images. The applied signal's voltages are displayed on the meter's Channel "B" (right) in all images. Signal input voltages were taken from Pin 9 (Triode) and Pin 7 (Pentode) respectively.
Testing and tracing a signal through a tube amp in this way is rather new to me and soon I plan to follow a signal from stage to stage and test for other characteristics of properly or improperly functioning stages. I'll be posting those results as well. But for now the results of the 7199 input jack, cathode and pentode signal injection.
Any and all observations and thoughts are appreciated. Meanwhile I'll be studying more.
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