Author Topic: How difficult to mod a Behringer UV300 for stereo vibrato?  (Read 434 times)

dimebucker

How difficult to mod a Behringer UV300 for stereo vibrato?
« on: January 05, 2021, 11:16:46 AM »
Hello all,

Just checking if this worth pursuing or would it be more hassle than its worth?

..maybe two UV300 pedals with rates somehow synchronized (180 offset)?


 :)

iainpunk

Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #1 on: January 05, 2021, 01:04:27 PM »
yeah, you need two of them and replace one of the LFO's with a signal inverter that doesn't change the bias level.

you take off the slave unit's DEPTH control, ignoring the outer pins and leaving a mark (piece of tape) on the wire that connected to the middle pin. and keep the unused LFO from working by taking out the RATE control

the master unit's DEPTH pot, you splice a wire to the middle pin to feed it to a daughter board containing basically this
it inverts the LFO without changing the bias. it works as long as the LFO isn't slower than 0.03Hz or 33.33 seconds

the output form this daughter board goes to the marked wire that was on the middle lug first.

cheers, Iain
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dimebucker

Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #2 on: January 06, 2021, 03:20:36 PM »
Cheers Iain, this is exactly the information I wanted.. I think I will attempt this!

Just out of interest, have you done this mod in the past or is this a general way to synch 2 vibrato boxes?

Thanks again :D

dimebucker

Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #3 on: January 20, 2021, 02:40:08 PM »
Looking for anyone to reply on this:


The circuit above shows a 10uf non-polarized capacitor, correct?

Would it be ok to use either a film or ceramic type?

antonis

Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #4 on: January 20, 2021, 03:08:43 PM »
It would be OK even with polarized electro..  :icon_wink:

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

iainpunk

Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #5 on: January 20, 2021, 04:58:05 PM »
yes, it could be a polarized one as well, and bigger is better. :icon_cool:

cheers, Iain
half man - half snail - 6 feet to scale - Snail man's - not frail - He's been - to jail - snail man is fuccing real
『snailpilled』

dimebucker

Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #6 on: January 21, 2021, 09:10:27 AM »
Ah, so the capacitor acts to remove high-frequency noise from the circuit  :)

Where do these high frequencies originate from? the opamp?

iainpunk

Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #7 on: January 21, 2021, 09:25:16 AM »
no, the capacitor is to eliminate the AC part of the LFO from that pin on the opamp, and to leave only the DC part in. if the AC isn't fully taken out at that point of the opamp, it won't nicely invert the signal, but just phase shift it slightly and you change the stereo effect.

you'll see that the filter breaks over at 0.03Hz, that translates to a wave of 33.333 seconds, this 33.333 sec wave is phase shifted 90 degrees. that means a pure sine of 3.333 seconds is fully flipped 180.

if you want to change the phase difference, you might want to change the 500k reisistor to a 500k potentiometer, so you can determine the phase offset between the two channels.

cheers, Iain
half man - half snail - 6 feet to scale - Snail man's - not frail - He's been - to jail - snail man is fuccing real
『snailpilled』

dimebucker

Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #8 on: January 21, 2021, 09:38:10 AM »
Excellent :D


Thanks, I fully understand now

iainpunk

Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #9 on: January 21, 2021, 09:46:15 AM »
ow, forgot to mention, its called an ''All Pass Filter'' by the way
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Ben N

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Re: How difficult to mod a Behringer UV300 for stereo vibrato?
« Reply #10 on: January 21, 2021, 10:14:02 AM »
Just out of curiosity, have you tried it just wet/dry?