Renegade channel 2 intermittent output

J

JamieTaylor1995

New member
Hi, wondering if anybody has had this problem before:

Earlier this week an EL34 blew on my renegade so this afternoon I swapped out both EL34s for new Tung-Sols and biased them to 70mV (In the renegade manual it states 65-75mV so right down the middle).
All was good for an hour or so and the amp was sounding great. I was in the middle of setting up channel 2 for recording when all of a sudden the amp all but died.

The signal now cuts out when a guitar is played as if there is a noise gate placed on the signal. There is no squealing/fizzing/hissing (although it is hard to tell as the signal cuts out so much).

I tried switching to channel 1 to see if the problem was present but no issue was found. i sweeped the tube mix knob right through from 6L6 to EL34 on both channels and this made no difference. Because of this I do not believe this is Power tube related.

I'm wondering if this is a heat related issue (cap/resistor maybe) since it took over an hour for the amp to fail or if the pre-amp tubes need changed?
possibly the pre-amp tubes in the channel 2 circuit have gone bad?
I doubt this is a transformer issue as channel 1 is fine? That's just me guessing though.

I haven't got round to checking/changing the fuses as it got too late for fiddling about with amps for one night.

Any help figuring out what is wrong will be greatly appreciated!
Just want my baby back up and running! :(
 

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Eracer":37aen8ez said:
http://www.egnateramps.com/download/RenegadeTubeChart.pdf

Since both sets of out put tubes are on channel 1+2. And you say that Channel 1 is fine selecting either set. Then it sounds like it could be the preamp tubes in Channel 2

Tubes 3+4 run in Channel 2 only.
Click to expand...

Hi Eracer,

Yeah, I thought as much.
To confirm, if I switch tubes 1&2 from channel 1 for 3&4 in channel 2 then the problem should move to channel 1?

Thanks
 
Update:

Managed to fix the renegade this afternoon by doing as I said above and switching the tube positions for each channel.
When I did this, the problem moved to channel 1, so I confirmed that at least one of those two preamp tubes were not working.

I had already noted that one of the tubes originally in the channel 2 circuit (V3 if anyone is interested) was a different brand to the rest of the tubes (the rest were the original egnater ones) - so I believed that this tube had already been changed at some point previously. (I got this amp second hand around 6 months ago - I know I should really do a full tube replacement but a lack of funds is preventing this at the moment)

I decided to take this tube out first to check if it was the culprit and sure enough, when replaced with a new 12ax7, the amp worked perfectly.

This had led me to wonder if V3 had been changed already because the original tube in V3 had died and someone did a straight swap?
Even though my amp is now working, i've started to wonder if the socket at V3 is supplying the tube with too much current causing it to die prematurely?
I'm possibly looking at an underlying problem with the components inside the amplifier here.
 
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