Question on Mark IV tone controls

I have always heard and read about the tone controls being pre-gain. So, I was playing around today trying to see exactly how much range I had in each control.

On the R2 channel, I turned down its treble to zero, and then the shared bass and middle to zero. I was somewhat surprised when I still got a sound out of my amp. I would have guessed that with all of them set to zero that I would have gotten no sound at all.

I tried the same thing on the lead channel - set all of the tone controls to zero. I got the same results. I expected to have gotten no sound out of the amp, but I did.

I tried turning the master volume all the way down - and still got some sound out of the amp.

My question(s): Is this normal for a Mark IV, or do I have a cap or something going bad?

Thanks in advance for your time and responses.

I would like to know too. I get the same behaviour.

greetings

AFAIK most if not almost all amps have their tone controls pre-gain, with the exception of maybe a couple controls that effect the power amp. Nothing special there.

The thing about the Marks is that the Graphic EQ is post gain, which is why it has such a dramatic effect on the amps overall tone. It's like putting an EQ pedal in the front of an amp vs putting it in a series fx loop; straight in doesn't offer much tonal change, but in the loop has a drastic effect because it is after the preamp.

I'm confused as to why you'd think cutting the lows/mids/highs would cut the signal...maybe the gain or lead drive if anything? The others will just shape the tone, no?

Thanks for the response. I do understand the pre-gain versus post-gain differences. I use those differences in shaping my tone.

The question was based on this line of thinking: If all 3 tone controls (not the graphic EQ) are pre-gain, then they by definition influence the signal. Thus, if I turned them all down to zero, would there then be NO signal going to the pre-amp? That was my theory. I was somewhat surprised when I turned them all down, and still had signal coming out of the amp. That caused me to question (1) was my hypothysis correct, or (2) was something wrong with my amp?

As a furthur test, I turn the 'output level' all the way down to 0. As with the tone controls being at zero, I would have expected NO signal to be sent to the speaker. I was again surprised to hear signal going to the speaker. Since this scenario did not directly involve the tone controls (and their settings), I began to question whether I did in fact have something wrong with my amp.

I have 3 other amps, and when I turn the master volume (or output level) on them down to zero, no signal is sent to the speakers.

That was when I decided to post a thread and ask my questions.

I hope my questions make sense.

Your amp is fine. Its a tone controll. There will always be a signal going trough!
Read the manual and you understand how the treble controll influences mid and bass.
Mid and bass influence treble to but in a whole other fashion.

The just influencethe tone. They dont cut it whole...