gain in clean channel

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CarolinaGearHead
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gain in clean channel

Post by CarolinaGearHead »

I've got a JTM60 thats acting odd. When on clean the overdrive gain is "bleeding" into the clean. Almost "ghost" like in the distant. Any thoughts? Maybe the signal relays? Thanks,Greg
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Stevem
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Re: gain in clean channel

Post by Stevem »

preamp tube.
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CarolinaGearHead
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Re: gain in clean channel

Post by CarolinaGearHead »

So Steve are ya sayin a preamp tube might be goin bad? Cause the only place where I can figure the overdrive section and clean section crossover is RL2. Also I've modded this amp considerably . The clean is close to a 1987 and the overdrive more towards a 2204. These mods are from Gunnar on the now defunct MetroAmp forum. Also would a filter choke, replacing R113, help any? Thanks again,Greg
thejaf
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Re: gain in clean channel

Post by thejaf »

I think he's saying it's likely a bad preamp tube. I had the exact same symptoms (ghosting distorted note) in a Bogner Shiva years ago, and it was a bad tube (second clean gain stage IIRC).
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CarolinaGearHead
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Re: gain in clean channel

Post by CarolinaGearHead »

Yeah thats it. I'll order a couple new ones. Any suggestions on tubes? Thinkin about Ruby Shuguangs. Any experience with those tubes? Thanks again,Greg
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billyz
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Re: gain in clean channel

Post by billyz »

The mullard reissue 12ax7 is sounding very good these days. Second place is the sovtek LPS. Nice detail, good tonal balance and pretty strong. Have worked well in several higain Marshall's in v1. Also improved a couple of blackstar's.
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CarolinaGearHead
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Re: gain in clean channel

Post by CarolinaGearHead »

Got it!! Relay2 has gone bad. Relay1 works as is should but #2 isn't switching as is should. All the associated trannys test good including the LED driver for the channel switching. Hopefully this can help someone else with this problem. Thanks to all,Greg
PS MetroAmp forum is back up and running well. My mistake thinking it was gone because the forum was down for a while.Greg
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