tremolo

[JDandCoke]

in an amp that has tremolo where in the circuit does it go?

 

is it right at the end after the amplifying bit? or at the end after the amplifying bit?

 

just wonderin

[JDandCoke]

no one?

[Kap'n]

Depends on the amp.

It's usually just before the phase inverter.

[comfortablynumb]

I've often wondered this myself.

[butterknucket]

Sometimes it modulates the bias of the output tubes.

[JDandCoke]

ok how about if im more specific...

how about...
where is the tremolo part in the following amps.
marshall bluesbreaker
AC30
fender blackface amps.

[JDandCoke]

bump

[jimmyc84]

Originally posted by butterknucket Sometimes it modulates the bias of the output tubes.

 

 

this applies to ac30s does it not?

[Kap'n]

Originally posted by jimmyc84 this applies to ac30s does it not?

 

 

It does not.

 

That applies to the brown, black and silver princetons, the brown deluxe, the tweed and brown tremolux, the tweed (and brown?) vibrolux, and the brown vibroverb.

 

Essentially all smaller brown and tweed Fenders with tremolo. And the pre '81 Princetons.

[JDandCoke]

Originally posted by Kap'n It does not. That applies to the brown, black and silver princetons, the brown deluxe, the tweed and brown tremolux, the tweed (and brown?) vibrolux, and the brown vibroverb. Essentially all smaller brown and tweed Fenders with tremolo. And the pre '81 Princetons.

 

 

you seem to know about this stuff but still wont tell me?

 

where does the signal get cut off?

before or after pre amp? power amp? at the end?

right at the beginning?

[Kap'n]

Originally posted by JDandCoke you seem to know about this stuff but still wont tell me? where does the signal get cut off? before or after pre amp? power amp? at the end? right at the beginning?

 

 

I don't have AC30 or Marshall schematics in my head, like I do Fender ones. Oh, and quit whining.

 

 

where does the signal get cut off?

 

 

 

Originally posted by Kap'n It's usually just before the phase inverter.

 

 

The exceptions, of course, for the BF Fenders being the aforementioned Princeton, and the Vibro Champ, which doesn't have a phase inverter. It modulates the cathode of the last gain stage before the power tube.

[JDandCoke]

Originally posted by Kap'n I don't have AC30 or Marshall schematics in my head, like I do Fender ones. Oh, and quit whining. The exceptions, of course, for the BF Fenders being the aforementioned Princeton, and the Vibro Champ, which doesn't have a phase inverter. It modulates the cathode of the last gain stage before the power tube.

thanks... so the the actual volume change is like between the power amp and pre amp?

i dont know much about amps see...

talking in simple terms...

it goes guitar... input... pre amp... trem... power amp... output stuff?

i need to learn amps like i know pedals

[erksin]

Originally posted by JDandCoke talking in simple terms... it goes guitar... input... pre amp... trem... power amp... output stuff? i need to learn amps like i know pedals

I think that is the most common circuit, yes...

[Kap'n]

In the larger BF-type amps, the tremolo comes right after the preamp, and cyclically grounds out the signal, using a "optoisolator," essentially a neon bulb and a photoresistor. Due to the way the bulb and resistor works, it makes a pretty choppy signal.

In the Vibro Champ, the tremolo is actually integrated into the preamp - modulating the gain of the second (final) stage. It makes a much rounder waveform, and the gain modulation makes for a nice warm organic sound.

The Princton integrates the tremolo into the power stage. It modulates the bias voltage of the power stage, again giving the round, warm sound.

[JDandCoke]

Originally posted by Kap'n In the larger BF-type amps, the tremolo comes right after the preamp, and cyclically grounds out the signal, using a "optoisolator," essentially a neon bulb and a photoresistor. Due to the way the bulb and resistor works, it makes a pretty choppy signal. In the Vibro Champ, the tremolo is actually integrated into the preamp - modulating the gain of the second (final) stage. It makes a much rounder waveform, and the gain modulation makes for a nice warm organic sound. The Princton integrates the tremolo into the power stage. It modulates the bias voltage of the power stage, again giving the round, warm sound.

i need to go back to school




















wait



















im still in school

[Kap'n]

OK, class is in session.

On a larger BF amp, it's as if somebody installed a volume control between the the preamp and power amp, and rather than using an audio taper pot, they used a linear taper. A robot turns the volume control up and down, but because the taper is messed up, it sounds choppy.

On the smaller ones, the robot changes your amp's bias up and down, making the tubes run hotter and colder. It's done in different ways, and in different parts of the amp, but the effect is similar.

[L6Sguy]

^^^
thanks for describing it in the way that my head was already picturing it in

[Kap'n]

Originally posted by L6Sguy ^^^ thanks for describing it in the way that my head was already picturing it in

I knew that. Next time put on your tin-foil hat, and make it more challenging.

[JDandCoke]

ok i think i got confused because i thought all trems were just volume controled... like the volume on a guitar (only a little more complicated maybe )

never thought of it as like biasing valves or anything haha

i just thought like an automatic volume control in various places...

i think i get it now

thanks!

[Kap'n]

Yep, it's one of the things about that bias modulation trem that make it so groovy. Nice and warm.

You can also find it on tweeds, and the brown Vibroverb.

The large brownface amp trem (Super, Pro, Twin, Showman). Now, that's a whole other story. I'm not even sure I can understand it completely, and I don't have a lot of experience with it.

I think

It splits the signal into high end and low end, tremolos one side, and uses an inverted signal to tremolo the other.

So as the highs are getting louder, the lows are getting quieter, and vice versa.

Or I could be wrong.