This Week on the Breadboard: the Subdecay Variac (Brownout OD)

And some oscilloscope shots.
IN - 1kHz, 200mV p-p. Yellow trace - output, cyan trace - out from TRE potentiometer. Different settings of GAIN and PENTODES pots. TRE @ 15, LOW @ 9.
MMBF5457 and MMBT5088

G @ min, P @ min
DS1Z_QuickPrint31.png

G @ 9, P @ 12
DS1Z_QuickPrint32.png

G @ 9, P @ max
DS1Z_QuickPrint33.png

G @ 12, P @ min
DS1Z_QuickPrint34.png

G @ 12, P @ max
DS1Z_QuickPrint35.png

G @ 8, P @ max
DS1Z_QuickPrint36.png
 
Good info!
The asymmetric clipping from the preamp section is quite apparent. Interesting that higher setting of PRE causes the preamp clipping to become more symmetric. The clipping at the output becomes more and more symmetric as PENTODES is turned up.
 
Chuck D. Bones said:
Good info!
The asymmetric clipping from the preamp section is quite apparent. Interesting that higher setting of PRE causes the preamp clipping to become more symmetric. The clipping at the output becomes more and more symmetric as PENTODES is turned up.
Click to expand...
We have two inverting stages here. I'm sure both are capable of clipping the signal. So maybe at some point we have more or less symmetric signal. I'm on a vacation now so can't test the circuit to check what's going on.
 
You must log in or register to reply here.
Back
Top