Crazy tone knob question

[MikeNiteRail]

Why is it that an amp with one, or even no tone control can sound so good? Why is it that an amp like the Bassman needs so many tone knobs? Wouldn't it work just as well to turn them all off like on a Champ?

I am sick of tone knobs. It is too much to fiddle with.

[brad347]

you could always bypass them!

If you like them in the 'neutral position' then you might indeed like it better. Every tone control introduces a 'loss,' and you might like them bypassed.

[MikeNiteRail]

I have a Bassman Ltd. How do I bypass them? Just turn them all the way down? I've heard that on Fender amps 0 isn't off.

Thanks! I'll give it a try.

[brad347]

no, you will have to modify the circuit.

Turning them all the way down will result in even more "loss."

I'm not familiar with the bassman LTD. Someone else will have to weigh in.

[MikeNiteRail]

I've heard that turning the tone control all the way up on an amp turns it off in some amps. It would be interesting to see what the differences are. My smaller amp only has one tone control, and I've never needed more.

[John Phillips]

The closest to bypassing them is to turn them all up to maximum, possibly except the Presence (which isn't part of the same circuit as the others).

Most amps have 'passive' tone controls, which are subtractive. So the least signal cut is to turn them all up full. Even then, turning them right up isn't necessarily going to give you the least-altered tone, mostly because the treble is essentially a blend control between 'treble' and 'middle + bass'.

The Presence control is actually quite different and works on the power stage, and controls the dynamics of the high frequencies - I'm not sure if it's technically classed as an 'active' tone control, but it behaves more like one. You probably don't want it right up, but once the rest of the tone controls are, and the power section is being driven hard as well, it becomes the most effective tone control, kind-of like an amp with just one.

The Bassman doesn't "need" so many knobs, but they are all useful and it really doesn't take a lot of fiddling to get the best out of them. (IMO)

[MikeNiteRail]

I can usually find a pretty good mix in all reality. You're right, if you know what you're doing then they can be really flexible. I never knew that about the presence control. Thanks!

[unklmickey]

The closest to bypassing them is to turn them all up to maximum, possibly except the Presence (which isn't part of the same circuit as the others)....


i think that depends on what you mean closest to bypassing, John

if you turn all the controls to max, you WILL get the least amount of loss. (these are passive controls). and the loss will still be significant, compared with bypassing this network. also, there will be a scoop in the midrange.

but IF the object is to get the least effect (flattest curve), then the settings are quite different from what you might expect.

http://guitarnuts2.proboards45.com/index.cgi?board=amp&action=display&thread=1150019343&page=1#1150220979


hope this helps,

unk

[John Phillips]

I know that, but it never sounds that way to me. The flattest response for the tone stack is 0-10-0, but that makes the amp sound extremely midrangy, as you would expect from turning the mids right up and the others to zero :).

This is because the rest of the amp, and in particular the speakers have a very strong midrange peak, with very little true bass and no actual top-end at all.

I think the values in the Bassman-style tone stack (which has become the basis for many, if not most, other designs via Marshall and others) were chosen/evolved precisely to compensate for that, and give what sounds like a very nearly flat response when all the controls are set to the same number position. Simply turning them all up full sounds like the most unaltered sound IMO, and definitely cuts less signal than any other setting.

[Johnny Z]

Do what I do on my old Twin, just set them on 10 and forget them. I do most my tone from the guitar.