ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

previous: R.G. q{I'll post other questions about t... -- 8/11/1999 5:05 PM

Re: Crybaby GCB-95 buffer ?

8/11/1999 5:44 PM
Arnaud	Re: Crybaby GCB-95 buffer ? Wait a minute, I roll up my sleeves ! 1) About the Small Stone. I have ever understood the basic phase stage(with a phase spliter). I have also understood the MXR trick with the JFET drain-source resistance controlled by the gate-source voltage. Thanks to your article, I have finally understood the Small Stone concept (my sleep has been disturbed for a long time...) with this "negative resistor" simulation. I haven't think a very long time since I read your article but I would have simply showed a part of the input voltage to the negative input OTA. It seems that both input voltage and OUTPUT voltage are equally showed to the negative pin. Would it work without the resistor between the output and the negative input ? 2) About the TB First, I must tell you I protoed it with AC 128's. My problem is that I admit the base-emitter diode with the 1N270 looks like a classical clipping section. But the transistor is not biased. Its base receive more or less current(controlled by the 'Fuzz' variable resistor) of the input signal. So when the input voltage is positive, the current goes in the 1N270 (so nothing on the collector) and when it's negative, it goes in the transistor base (so a current appears in the collector). THIS IS NO CLIPPING AT ALL. IT'S JUST A TERRIBLE MESS. In fact, I'm sure my explaination is totally wrong. Help me. I also measured -35mV at the Q3 base. WHY ??? The transistor is not biased at all!!! One last question (I started a collection): I found a bunch of Ge diodes in my father's components box. They are labelled with colors like resistors (just like the AA119 I've purchased). Does anyone know this diode code?

8/11/1999 5:44 PM

Arnaud

Re: Crybaby GCB-95 buffer ?

Wait a minute, I roll up my sleeves !

1) About the Small Stone.

I have ever understood the basic phase stage(with a phase spliter). I have also understood the MXR trick with the JFET drain-source resistance controlled by the gate-source voltage. Thanks to your article, I have finally understood the Small Stone concept (my sleep has been disturbed for a long time...) with this "negative resistor" simulation. I haven't think a very long time since I read your article but I would have simply showed a part of the input voltage to the negative input OTA. It seems that both input voltage and OUTPUT voltage are equally showed to the negative pin. Would it work without the resistor between the output and the negative input ?

2) About the TB

First, I must tell you I protoed it with AC 128's.

My problem is that I admit the base-emitter diode with the 1N270 looks like a classical clipping section. But the transistor is not biased. Its base receive more or less current(controlled by the 'Fuzz' variable resistor) of the input signal. So when the input voltage is positive, the current goes in the 1N270 (so nothing on the collector) and when it's negative, it goes in the transistor base (so a current appears in the collector). THIS IS NO CLIPPING AT ALL. IT'S JUST A TERRIBLE MESS. In fact, I'm sure my explaination is totally wrong. Help me. I also measured -35mV at the Q3 base. WHY ??? The transistor is not biased at all!!!

One last question (I started a collection): I found a bunch of Ge diodes in my father's components box. They are labelled with colors like resistors (just like the AA119 I've purchased). Does anyone know this diode code?