VH4 Channel 2 not working

[stevemac1]

Hi all,
I'm a newbie to this forum but have owned a Diezel VH4 for a number of year and absolutely love the amp. Best purchase I ever made. A few weeks ago I took the amp to a local repair shop in Massachusetts to have the tubes replaced. The amp is about 4 or 5 years old and the tones were starting to change so I felt it needed new tubes. The shop replaced the JJ KT77s and the preamp tubes and biased them all but when he finished he said that channel 2 would not work. Channel 1, 3 and 4 sound great. On channel 2 you can hear a slight hum - like the channel is working but no sound will come out. Has anyone had this happen? If so, is there a repair that the shop can do. The amp is obviously out of warranty. Any help / thoughts would be greatly appreciated. Thanks.

 

[Ventura]

No sound at all???? Just a hum????? Does the hum get louder when the MV or CV get turned up/down????

More importantly - did it work BEFORE going to the repair shop???

 

[stevemac1]

No sound at all???? Just a hum????? Does the hum get louder when the MV or CV get turned up/down????

More importantly - did it work BEFORE going to the repair shop???

Hi, thank you for the reply. Yes, it did work (all 4 channels) before I took it to the repair shop to have it re-tubed. The hum is a low hum and it does get slightly louder when I turn up the master volume and the channel volume. The hum sounds different than the other 3 channels - its a lower hum.

 

[Ventura]

I'm sorry to say - this is going to have to rest on the responsibility of the repair shop then. 100% - if all channels were working going INTO the shop, but Ch.2 is NOT working coming out of the shop - math is simple. They fucked something up and need to fix it.

 

[Ventura]

If it's an OLD VH4, it could be a fault preamp tube (V4), but if it's a relatively modern VH4, then V1 supplies all channels, and Ch.2 relies on V3 and V4, as do all the other channels (save for V3 NOT supplying Ch.1)

I doubt one side of a preamp tube would result in only a hum - I'm not digging this at all... Let us know what's happening and good luck.

 

[stevemac1]

If it's an OLD VH4, it could be a fault preamp tube (V4), but if it's a relatively modern VH4, then V1 supplies all channels, and Ch.2 relies on V3 and V4, as do all the other channels (save for V3 NOT supplying Ch.1)

I doubt one side of a preamp tube would result in only a hum - I'm not digging this at all... Let us know what's happening and good luck.

Thanks. I agree it is totally the responsibility of the repair shop. The owner is telling me that he does not know how to fix this issue. I'm going to keep digging into it. I'll let you know what happens.

 

[Ventura]

Thanks. I agree it is totally the responsibility of the repair shop. The owner is telling me that he does not know how to fix this issue. I'm going to keep digging into it. I'll let you know what happens.

I would politely ask him to find out who he/she recommends and can entrust working on an amp of this calibre and to kindly pick up the invoice for such services. Sounds to me like this might be a donkey in a china shop situation and ya, I'd be a little concerned about some hack with a solder gun "trying" to figure out WTF went wrong. If he doesn't know, find someone who does - properly - and get this current guy to cover the costs. Not trying to add to the scene here, but this would have me fkn furious. You're taking this amazingly well. I'd be livid.

But ya, try to find the RIGHT tech, and have the other tube-guy tech pick up the bill. I'd also send a request in to Diezel HQ for them to see the problem, they could have someone in your area or close by to assist with *actual* knowledge.

 

[stevemac1]

yeah, I agree. I am bullsh*t at this "repair" guy because he doesn't seem to care about getting the amp fixed. I have told him he will need to pick up the cost. I did get an email from Peter at Diezel (I'm assuming its the man himself) and he gave me the name of a shop that should be able to do the repair. I'll keep you updated.