Vox Tremolo - Required for AC30 Sound?

[MarshallPlexi]

Guys I read an article on the AC30 at http://www.tone-lizard.com/Vox_Myths.htm and there the guy states the the 'secret' tone of the AC30 lies in the way the second half of the phase inverter is tied to the tremolo. What do you guys think? Is this true? Does the phase inverter need to be tied to the trem in order to sound like the quintessential AC30? It seems that if the speed control were set to it's minimum value that this phase inverter side would be tied to ground just like every other AC30 schematic I've seen.

Any thoughts?

Once you click on the link, scroll down till you see this image:


[img:379:314]http://www.tone-lizard.com/images/AC30_notch.gif[/img]

[paulster]

When that 500K pot is turned down to zero, where will the input to the right-hand side of the PI be tied to?

Answer: to ground, via a very low impedance source, i.e. it'll be tied directly to to ground.

[MarshallPlexi]

My thoughts exactly! Now why did this guy write that this circuit is part of the mojo of the AC30? I don't get it.

[paulster]

It is fed from the Tremolo channel, and the coupling features a very clever 'notch' filter. Voiced in the midrange of the guitar frequencies, this gives the AC30 its characteristic 'honk'.

Also mentioned is that having the Volume on '0' removes the notch filter from the circuit, and thus it cannot have any effect on the 'Normal' or 'Brite' channels. This is absolutely true, but I mentioned it solely on the observation that no one I know uses the 'Normal' or 'Brite' channel.

So, he's basically saying that the tremolo channel is the only one that has the characteristic AC30 sound.

I beg to differ.

[MarshallPlexi]

Okay I thought I might be missing out by not having the trem. I guess I'm doing okay.

Thanks guys!

[KT66]

If you read the whole article at Tone-lizard.com about the AC30, Randy states that "...As long as the Volume control is set to '0', the grid is at AC ground. Fair enough. Also mentioned is that having the Volume on '0' removes the notch filter from the circuit, and thus it cannot have any effect on the 'Normal' or 'Brite' channels. This is absolutely true, but I mentioned it solely on the observation that no one I know uses the 'Normal' or 'Brite' channel."

For what it's worth here's a couple of interesting links regarding the AC30:

http://www.geocities.com/vintage325/topboost.html

http://www.thevoxac30guide.com/

Cheers,

[jaysg]

This is absolutely true, but I mentioned it solely on the observation that no one I know uses the 'Normal' or 'Brite' channel."

hmm...Brian May uses the Normal channel with a treble booster. Perhaps a unique situation, but an interesting choice.