Vox AC30/ 6 (TBX). Add an MV ?

[Sea Chief]

A preamp volume controls the signal volume (or level) to all following amp stages including the power amp.
Should be obvious, no?
All non-master volume amps only have preamp volume.

Hi HH.

Ok this is obviously the crux of why I haven't been able to grasp things so far. When there's this 'signal path' I visualise a beginning/in & end/out: beginning being guitar in, then along a chain of preamp xyz, then to the power amp stage, then ultimately OUT after this. Left to right.

The two box diagram suggests this 'lineage/ linkage' too, so had just always assumed the 2nd box Vol.. is always there (& may be called Vol if there's one, or MV if there's ALSO one added into the preamp) .. & the added preamp Vol can be introduced (as MV) in either Vol guise, or Gain guise. That is what I had learnt from the thread. But with huge complications, because this doesn't seem to be right all along.

Last night I then quizzically look at my hifi preamp & poweramp. And it clicks that the Vol knob os on the preamp & not the poweramp: I had thought you see there was no correlation between a SS hifi amp, & Tube guitar amp. So it seems there has been all along.

Ok I've now got to re-evaluate & consider this single Vol on the preamp, & split it from the power amp, in my head. At the moment.. because the above was locked into how I perceived things.. it isn't registering. I can't visualise it. It still seems illogical.

Thanks, SC

[Sea Chief]

This isn't to say I've got it now, at all though. I'm for the first time ever, looking at my (two boxes) hifi amps wondering what the heck is actually going on!

A path you see, in the literal sense has a beginning & end, a line. It seems in the case of an amp, the path goes forward.. from preamp to power amp (the boxes digram DOES show this path L to R after all).. then instead of "exiting" in a linear way RHS, it instead sort of doubles-back into the preamp.

This is now how my head is having to consider things. And tbh it's not possible for me at this juncture, to visualise it, or make logical sense of this U-turn (& likely totally wrong way of considering it anyway). I wonder if anyone can put themselves in my shoes here. How, I'm thinking of things wrongly.

Thanks, SC

[Chuck H]

Ok... Let us try another graphic.

[Chuck H]

The above is just one example. Different pre amps have different clipped waveform characteristics. But always different from the power amp and almost never symmetrical like power tube clipping.

[Sea Chief]

The above is just one example. Different pre amps have different clipped waveform characteristics. But always different from the power amp and almost never symmetrical like power tube clipping.

Hi Chuck, I'm still not able to grasp the preamp to power amp though. Irrespective of any distortion characteristics of different settings.

So in effect since HH's stating that my amp only has a Volume control in the preamp, I've gone back a step. I'm back to re-evaluating how an amp works.

So my innitial asking about introducing an MV.. is far in advance of where my understanding is now. That is IF my thinking of there being a similarity between my hifi two-box setup, & a guitar amp, has validity: I don't know whether using this as a reference is a valid learning 'tool'.

That said, your diagram chimes with using an amp with two knobs one Vol & another MV: I only recently had my Music Man 4-10, so remember the results from the two knobs interacting, even if I didn't know how an amp works (realising this only just now).

As to how the MV -only- affects the power amp section in your diagram.. this is WAY in advance of where my understanding is. I haven't on god's earth got a clue as to why or how an MV can affect just the power amp, if it's placed before it (& if that's where your diagram suggests it is placed).

But again thanks for trying to help- I'm unfortunately off on an unintentional trajectory though presently, trying to get the idea of a single Volume knob residing in the preamp, not as I had resolutely had it placed in my head for 35 years, that being at 'the end of the path' in the (end) of the power amp, before the spkrs.

Thanks, SC

[loudthud]

The OP doesn't seem to have a clue how things work.

Please answer these questions.

1) The pickups in a guitar convert the wiggling of the strings into an electrical signal. If you just connect a cable from your guitar to a speaker cabinet, why doesn't it make any noise ?

2) In a guitar amplifier, the Input jack is connected to a couple of resistors, then it is connected to a tube. Why is it done this way ? What does the tube do t the signal ?

[Sea Chief]

The OP doesn't seem to have a clue how things work.

Please answer these questions.

1) The pickups in a guitar convert the wiggling of the strings into an electrical signal. If you just connect a cable from your guitar to a speaker cabinet, why doesn't it make any noise ?

2) In a guitar amplifier, the Input jack is connected to a couple of resistors, then it is connected to a tube. Why is it done this way ? What does the tube do t the signal ?

I don't care to reply to mildly angry sarcasm dressed as helpful questions, thanks.

SC

[Sea Chief]

Can anyone tell me if my two separate SS hifi boxes (preamp & poweramp), is a useful 'tool' to compare to the preamp/ poweramp stages in a Tube guitar amp?

Thanks, SC

[nosaj]

No. Hifi are meant to be clean. Guitar amps can be both.
noth

[Sea Chief]

No. Hifi are meant to be clean. Guitar amps can be both.
noth

Of course I understand this, distortion wasn't part of the enquiry at all.

I'm back a step nosaj. I'm trying to get my head around the idea of a single volume control, affecting the power amp, located in the preamp. As of yet, I can't visualise a power amp section, without having a volume control: the power amp seems to me to be at the end of the path, with the very last part being the output to the speakers. So I always thought the volume control would be located here, just before the speakers, affecting what is ultimately SENT to the speakers. I also know that you put an attenuator HERE, between the power amp.. & the speakers, further confirming (wrongly as I now am told) that Volume knobs just go right here.

So, is my hifi two-box separated preamp & poweramp, with it's volume control on the preamp, a good example for comparison (regardless of distortion which is irrelevant)-?

SC

[Greg Robinson]

If you turn the volume control on your guitar down, it mutes the output of the amp right? It's not only "before" the power amp, but the preamp too. So why is a volume or "gain" control in the preamp muting the power amp a difficult concept for you to understand?

[loudthud]

As to how the MV -only- affects the power amp section in your diagram.. this is WAY in advance of where my understanding is. I haven't on god's earth got a clue as to why or how an MV can affect just the power amp, if it's placed before it (& if that's where your diagram suggests it is placed).

You don't seem to understand signal flow. Do you expect the signal to go backwards through the Master Volume and affect the Preamp ? Do you know what a Voltage Divider is ?

Are you refusing to answer the questions because you don't know the answers ?

Are you one of these AI Robots that just posts stuff to get a reaction from people.

[Sea Chief]

Ignored.

[Sea Chief]

If you turn the volume control on your guitar down, it mutes the output of the amp right? It's not only "before" the power amp, but the preamp too. So why is a volume or "gain" control in the preamp muting the power amp a difficult concept for you to understand?

Tbh I've never considered how turning the gtr vol down can actually make the amp vol diminish.

Now I am thinking how on god's earth this happens. So I've got another connundrum to consider.

I might hazzard a guess though, that it diminishes the signal going from the guitar into the preamp. IE if it's 0.5mV at gtr vol 10, then it's 0v at gtr vol 0. If it's a pot on the guitar, it can only affect whatever's emanating from it. I have no idea though.

SC

[loudthud]

Moderators: I don't think he's going to get it. Please close this thread.