1979 Super Reverb - Distortion on Vibrato Channel

[g1]

What kind of clipping is the story when the signal on its way DOES NOT PASS through V3.

Have you seen 'diode clipping' (some Marshalls use it) where the signal does not actually pass through the diode? The principle here is the same.

[vintagekiki]

Have you seen 'diode clipping' (some Marshalls use it) where the signal does not actually pass through the diode? The principle here is the same.

Dear Colleague
I'm really interested how the clipping signal occurs or how you say ‘diode clipping’ if the signal does not pass through the diode.
I would ask that the explanation be engineering and not superficial.
What do I know, maybe I'll learn something new.
Point on the schematic on which element the clipping signal occurs.

[Helmholtz]

Here's a screenshot of an E chord played directly into the scope with a LesPaul (medium output Burstbuckers):


A far cry from the Fender reference level of 3.5mVrms = 10mVpp. Starting from around 900mVpp, the peak-to-peak values are still above 200mV after 3 seconds.

Schematic reference signal levels are typically chosen low enough to allow all amp stages to operate within their linear range.
This ensures that the nominal gains of the stages can be calculated from the input and output signal levels for reference purposes.

Of course players don't care about reference levels .

[g1]

Dear Colleague
I'm really interested how the clipping signal occurs or how you say ‘diode clipping’ if the signal does not pass through the diode.
I would ask that the explanation be engineering and not superficial.
What do I know, maybe I'll learn something new.
Point on the schematic on which element the clipping signal occurs.

Here is from Marshall 2550 circuit with clipping diodes. The principle is the same. Removing diodes does not prevent amplifier from working.

[vintagekiki]

With regret I may notice that some things you obviously do not understand.
I will use your phrase "The principle is the same"
As with diodes, "the principle is the same" can be said for C19, C21 (treble cut), C4 (bass boost)

Let's go back to your diodes.
Don't you think that resistor R29 and 5 diodes represent the voltage divider, which means that the signal "passes" through the diodes.

[g1]

Let's go back to your diodes.
Don't you think that resistor R29 and 5 diodes represent the voltage divider, which means that the signal "passes" through the diodes.

To ground?
Your blue line shows the signal path. You do not show a path through the diodes. The diodes do the same as the grid of V3 in the Fender can do (when driven to grid conduction).

Will the amplifier work if you remove V3?

Will the Marshall amp work if you remove those diodes?

Do you understand that those diodes in the Marshall are used specifically for clipping the signal?

[The Dude]

I think actually the clipping diodes in that circuit are D4 &D5, but that's not the point. In a typical clipping diode circuit, there is a signal voltage across the diodes. They don't do anything until a certain signal voltage/level is reached and they begin to conduct, chopping off signal peaks. So, who's right in the argument depends on signal level.

[g1]

They don't do anything until a certain signal voltage/level is reached and they begin to conduct, chopping off signal peaks. So, who's right in the argument depends on signal level.

I'm not meaning to argue, just trying to relay the concept of the reverb driver tube clipping the signal if there is grid conduction. And the same thing you mention about the signal level you is also true there.

Once again, I think we run into a brick wall with the whole 'google translate' business. It is unfortunate.

[The Dude]

Yes. I agree with the theory laid out if that wasn't clear.