Problem with VH4 parallel return -solved-

Bullseye

Bullseye

Member
Hey everyone,

I have owned my VH4 for 14 years now and never had a problem with the parallel loop until today. I only use the parallel loop for delay. I have been using an old Roland 2500 in the loop. Well today, I start to play and notice there is no delay to be heard, only a dry signal.

Looking at the face of the Roland 2500, it is getting plenty of signal. I checked the mix knob for send 2 and it was exactly where it has been for years.

I tried the VH4's series loop and delay can be heard. I tried a different delay in the parallel loop and had the same result; dry no delay, but signal was going into the delay, just no echo coming back to the amp.

I put a jumper cable between send 2 and return 2 and there was no signal loss to indicate a bad input jack.

I look forward to hearing some helpful hints as to what I can do to get my parallel effects loop working properly again.

Best wishes,

Bullseye
 
My guess is bad 12ax7 for parallel loop. If you’ve never changed them 14 years is a good run. Think that’s V6, next to last one on a new VH4 but I could be wrong. Different generations have different numbers of tubes.

I’d change out the preamp tubes one at a time with known good ones and see if it helps. It definitely wouldn't be V1, so I’d start at the far end away from the input and work backwards.
 
Thank you for the advice! I will plug a new tube in V6 in the morning! My only concern is, that V6 is the return for series loop as well. Once again, thank you so much for the point in the right direction!

I will report back with the good news or the bad.

Best wishes,

Bullseye
 
Let us know what you find. 12ax7 tubes have 2 triodes if you didn’t know, so one half the tube controls serial return, the other half would be parallel return. It’s entirely possible to only have one triode fail, so your serial would work but not the parallel or vice versa. ?
 
Bullseye":3ldx90zj said:
Hey everyone,

I have owned my VH4 for 14 years now and never had a problem with the parallel loop until today. I only use the parallel loop for delay. I have been using an old Roland 2500 in the loop. Well today, I start to play and notice there is no delay to be heard, only a dry signal.

Looking at the face of the Roland 2500, it is getting plenty of signal. I checked the mix knob for send 2 and it was exactly where it has been for years.

I tried the VH4's series loop and delay can be heard. I tried a different delay in the parallel loop and had the same result; dry no delay, but signal was going into the delay, just no echo coming back to the amp.

I put a jumper cable between send 2 and return 2 and there was no signal loss to indicate a bad input jack.

I look forward to hearing some helpful hints as to what I can do to get my parallel effects loop working properly again.

Best wishes,

Bullseye
Click to expand...


If you use the parallel loop without FX it should work as a second master because more signal is fed into the power amp. If you turn the loop knob up, the amp should get louder actually.
When using a delay, you have to kill the dry signal in the delay!
 
RyeDaddy you were right!!!! It was V6 that was causing the problem! Thank you so very much for your help!!! I'm sure my neighbors weren't too happy to hear Mr. Scary blasting from my VH4 at 6:30 this morning (haha)!!! :D

Best wishes,

Bullseye
 
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