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could this be done?

Posted: Thu Jan 24, 2008 12:19 pm
by Progrockabuse
i think most people know i this forum that i'm after a tremelo pedal. which i want to replace the tremelo i had on my vox before the vox died.

my question is, could i take the trem circuit out of the vox, as this still works and put it in a pedal? i think i'd have to modify it alot, but i thought it'd be an interesting project.

thoughts?

Posted: Thu Jan 24, 2008 12:21 pm
by Mike
This would probably result in a dead Vox and a dead you.

Buy a Danelectro Tunamelt Tremelo and keep your ticker beating.

Posted: Thu Jan 24, 2008 12:35 pm
by Progrockabuse
Mike wrote:This would probably result in a dead Vox and a dead you.

Buy a Danelectro Tunamelt Tremelo and keep your ticker beating.
yeah good plan, just wanted an excuse to take something apart, i'm off work today lol
had an appointment to get me carple tunneling done.

Posted: Thu Jan 24, 2008 12:38 pm
by Mike
If you wanna take something apart for kicks an Amp should be last on your list really.

Here lies Electrocution.

Posted: Thu Jan 24, 2008 12:39 pm
by jon183
take a look at the Seymour Duncan Shape Shifter. I just got mine. Its a Tap Trem thats 100% analog sound with a digital brain allowing you to modify the crap out of your speed and wave and stuff while still getting you that same great amp trem kinda sound. I can demo it for ya if youd like.

Posted: Thu Jan 24, 2008 12:47 pm
by Progrockabuse
Mike wrote:If you wanna take something apart for kicks an Amp should be last on your list really.

Here lies Electrocution.
i'm scrapping it anyway, unless i could use it as a cab. it's one of those cambrige 30 ones, the tranny with one tube.

the clean channel goes haywire, aparrently it's a fault with all the cambridges. hence why they were scrapped.

if someone wants it to fix up, they could have it.

Posted: Thu Jan 24, 2008 12:50 pm
by Progrockabuse
jon183 wrote:take a look at the Seymour Duncan Shape Shifter. I just got mine. Its a Tap Trem thats 100% analog sound with a digital brain allowing you to modify the crap out of your speed and wave and stuff while still getting you that same great amp trem kinda sound. I can demo it for ya if youd like.
yeah i've heard about those pedals, never tried a seymour duncan fx before. a demo would be cool. i cant make up my mind what trem i want, i just need a trem lol

Posted: Thu Jan 24, 2008 4:35 pm
by filtercap
If you're curious whether it can be done in principle, the answer is... maybe. An amp trem circuit is basically a low-frequency oscillator with a knob to control how fast it oscillates and another knob that determines how much the oscillations affect the guitar signal going through the amp. In tube amps, this guitar-signal-affecting bit is done one of two ways.

-- On some amps, especially older ones, the oscillator is set up so that it constantly changes the bias of the power amp tubes. Your sondz get quieter as the tube bias gets colder, and louder as the bias gets warmer. To isolate this to a pedal, you'd have to include a separate tube stage to give the oscillator a bias to futz with.

-- Other amps set up the trem oscillator so that it sends part of the guitar signal to ground. This is often done using a light-and-photocell gadget whose resistance changes as the oscillator changes the voltage going to its light. The amount of guitar signal that gets grounded out changes constantly as the oscillator does its thing, and you get that trem sound. This type would be easier to isolate to a pedal.

With your mostly solid-state Vox, I suspect it uses this second type of oscillator, the kind that doesn't need to interact with the power amp. And it likely uses some transistors to do the oscillating, not that one tube. That would mean the circuit needs much lower voltages to operate and would be easier/safer to move to a pedal. If you weren't scrapping the amp, you'd want to be very careful to make sure that you weren't leaving some broken or shorted circuits behind.

Like Mike was saying, it's definitely not the type of thing you'll want to try until you've studied amps enough to spot the trem circuit in a schematic and understand what it's doing and the voltages it needs. But at that point, you'd probably be able to fix the amp up just as easily as make its trem work in a pedal. :)

Posted: Thu Jan 24, 2008 4:45 pm
by Progrockabuse
i think i'm just going to leave it well alone. i've settled for a tuna melt, which will be here tomorrow. finally i've put an end to my wingeing, for now lol. :D

Posted: Thu Jan 24, 2008 5:05 pm
by kim
trem is cool, dano tuna melt is cool, i'm selling mine, don't know why, too tempting to put it on my board when it's here i think, i want less pedals

Posted: Thu Jan 24, 2008 5:13 pm
by Progrockabuse
heavium wrote:trem is cool, dano tuna melt is cool, i'm selling mine, don't know why, too tempting to put it on my board when it's here i think, i want less pedals
wish i'd know earlier you might be selling one. :( is this for the or50 fund? :)