Behringer UC200 Chorus LFO smoothing

A forum devoted to mod, tips and suggestions for upgrading and rehousing your VERY CHEAP commercial stompbox to near boutique excellence.
Post Reply
User avatar
SirPrimalform
Information
Posts: 2
Joined: 31 Aug 2016, 10:40

Post by SirPrimalform »

It sounds to me like it has a triangle wave LFO and if you plug a dummy lead into the dry output the main output goes wet only and becomes a cool (if weird) vibrato. It got me wondering whether it would be possible to filter the LFO a touch to give an optional different character to the chorus/vibrato.
My thinking is that the depth pot is probably a voltage divider so putting a cap between the output of that and ground shouldn't be too hard, does this sound right? If it sounds good I'd try and find a place to add a switch so I can go back to the original sound.

Does anyone know what it's based on and if there's a schematic to check my guess?

User avatar
uncleboko
Cap Cooler
Information
Posts: 509
Joined: 25 Mar 2008, 20:19
Has thanked: 58 times
Been thanked: 41 times

Post by uncleboko »

Here is the UC 100, which is probably very similar to the UC 200
Attachments
Behringer_UC100_Ultra_Chorus_Schematic.pdf
(59.82 KiB) Downloaded 349 times

User avatar
SirPrimalform
Information
Posts: 2
Joined: 31 Aug 2016, 10:40

Post by SirPrimalform »

Excellent, much appreciated! I imagine the UC200 is a minor revision like a version 1.1 as they seem to have the same features.

Ok, the depth pot VR5A looks like a voltage divider but the lower side is not tied to ground but rather the junction of R16 and R17, which I guess is a biasing reference, looks like it might be V+/2 as they're both 10k. Does this mean I'd want to tie my smoothing cap to that reference voltage rather than ground? I'm just making an (only slightly) educated guess so I'd be really grateful if someone could correct me if I'm wrong or otherwise confirm my understanding.

User avatar
hemisfeer
Information
Posts: 37
Joined: 18 Oct 2015, 14:55
my favorite amplifier: Fender Hot Rod Deville 410
Completed builds: A lot of the BYOC catalog as well as some ModKitsDiy pedals. Looking to venture in to amps someday. Need to learn some more
Has thanked: 10 times
Been thanked: 19 times

Post by hemisfeer »

Hey all, I just bought a Behringer UC200 as a repair project. The complaint in the add was output B had a lower level than output A. My question is, is there supposed to be chorus effect on output B? Or this this a dry signal only output? Thanks!

User avatar
hemisfeer
Information
Posts: 37
Joined: 18 Oct 2015, 14:55
my favorite amplifier: Fender Hot Rod Deville 410
Completed builds: A lot of the BYOC catalog as well as some ModKitsDiy pedals. Looking to venture in to amps someday. Need to learn some more
Has thanked: 10 times
Been thanked: 19 times

Post by hemisfeer »

Hey everyone, I just did a quick test with an ABY box and when using both outputs, A is the vibrato part of the chorus, and B is the dry signal. When using just A, I get a good strong signal out and when I mix the two, A is a bit distorted and the summed output is a little less than it should be. I'm guessing there's something wrong in the circuit before the dry signal gets out. The UC100 schematic from
uncleboko is going to be handy.

Post Reply