Hey guys,

So I got a Retro-Sonic Chorus Ensemble pedal because I love that early 80s/late 70's Boss CE-1 sound to death. However, when using it in the effects loop of my Ampeg Vh140c, I get that dreaded HUMMMMMMMMM in the note of B when I engage the chorus. I've got the guitar input going right into the amp. The line out on the fx loop goes into the chorus's input, and from the chorus, the out is going into the head's fx loop line in. I got some electric contact cleaner to flush the amp out and that didn't do anything. What could be going on here?

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Do other pedals in the fx loop also sound noisy? If not, it sounds like it's the pedal's problem. If it's a very loud persistent hum it could be a grounding issue but I doubt it if your amp is quiet when you have no effects in the loop.

Doesn't the VH140 have like 2 or 3 different FX loops? (like 1 line in and out, then 2 true Send/returns for stereo effects, one being with chorus engaged and another one dry)? Try it through all of them.

And if you like retro 80's type chorus why don't you just use the ampeg's chorus?

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Haha, yeah, good point, but the VH140c's chorus sucks alot of the tone out when you turn it on. It also doesn't have the same quality as the Retro-Sonic but it is the same basic idea. Plus, the chorus on my VH140c is kinda... fucked up. Sometimes the knobs wont do shit and then they'll start working. The chorus is the only thing farked up about my VH140c besides the fact that the reverb channel gets really noisy when I turn it past 12 o'clock.


I have no other pedals to try this out with, but I'll be getting a Boss DD20 later today so we'll see. My amp doesn't make any other noise on its own at all. I've patched the effect loop out into the in before to see what it would sound like, and that didn't make any hum either.


Yep, I just tried routing from the effects loops from the back of the amp, and I still get major hum every time I turn the pedal on. So far it looks like it's totally the pedal's fault, but when I get my DD20 later we'll see if that's true or not.

EDIT: Tried the VH140c's polarity switch also... didn't work.

EDIT 2: When running the pedal as guitar -> pedal -> amp input, I don't get the hum when I turn the pedal on. I am confuxxored. This is only happening in the effects loop

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Try inserting just 1 guitar cable -nothing else- between the fx send and return, like if you were "jumpering" them. If you get no noise/hum at all, it's definitely the pedal.

If you still do get hum, try twisting the cable's connectors on the fx send and return jacks, if the noise comes in and out, then it's the jacks. Get em cleaned(or replaced, they're inexpensive).

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Already tried it on all 3 fx loops... I get no hum or noise at all when I put the send into the return jack. What's really weirding me out is like I said... the thing doesn't hum like a mother when I do guitar -> pedal -> amp input.

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FIXED IT.
I used the power supply that I bought for my Boss DD20 on the Retro-Sonic. The other power supplies I was using before were 9 volts also, but the Boss ones appear to be regulated. I'm just glad I found out what the hell was causing that hum. Thanks for your help Soeru! I will clean my jacks anyway to see if I can totally reduce the noise on my Ampeg.

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Cool to hear it works. Power supplies can make a big difference. I'm still baffled how it only creates noise when it's off though.

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Boss pedals are not true bypass. They use a buffer to drive the signal and maintain it while switching to prevent the mechanical "pop" of true bypass.

I'm thinking the old power supply was reversed in polarity.

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