Problem with DC-3 - Need Help

[MJ Slaughter]

I need some help with my DC-3. It's been running great, a month a go I put new EL84s in it and it hasn't shown any signs of trouble. Now the volume level is so low I can crank all the levels up on either channel and there is not much output. Might be great for a bedroom player.

Saturday I noticed some static and a lower frequency hum but otherwise it sounded normal. Today I turn it on, it sounds like the day before with plenty of volume with the same noise. I proceed to replace each preamp tube one at a time. After putting a different tube in V2 it was quite and I thought, great it's fixed. Problem was it is quite because there isn't much volume. I don't know if V2 is the problem. It could have been coincidence and like I said the volume loss is on both channels and V2 is for the lead channel only. I go back through swapping preamp tubes with a different one in case the first was bad. Did this like 2 other times different tubes. Swapped the power tubes with my previous backup set which were working fine last time in the amp. Still the same problem.

What could have initially caused some static then drastically reduced the volume? Any help is appreciated.

 

[jestaudio]

try bypassing the effects loop with a patch lead, my dc5 had a similar problem wihich this cured, is so replace the effects loop jacks or give them a good clean, apart from that PM Monsta-Tone, chances are he can point you in the right direction

 

[MJ Slaughter]

Thanks for the reply jestaudio. Unfortunately I already tried that yesterday with no improvement. Cleaned the send jack and put a jumper between the send and return. My concern is that the output transformer needs replacing but I'd like to confirm that before spending the money.

 

[jestaudio]

Thanks for the reply jestaudio. Unfortunately I already tried that yesterday with no improvement. Cleaned the send jack and put a jumper between the send and return. My concern is that the output transformer needs replacing but I'd like to confirm that before spending the money.

out of interest have you tried the PI tube for a known good one, it would also be worth checking if you have a nice glow from the output tubes, chances are its not serious, usually boogies are pretty much bullet proof so i would suspect its tube related

 

[MJ Slaughter]

Thanks for the reply jestaudio. Unfortunately I already tried that yesterday with no improvement. Cleaned the send jack and put a jumper between the send and return. My concern is that the output transformer needs replacing but I'd like to confirm that before spending the money.

out of interest have you tried the PI tube for a known good one, it would also be worth checking if you have a nice glow from the output tubes, chances are its not serious, usually boogies are pretty much bullet proof so i would suspect its tube related

I did try a good tube for the PI and the power tubes all have a nice health glow. Even my backup set. I too would be surprised if it's serious but the amp is getting kind of old.

 

[MJ Slaughter]

I feel a bit foolish. Problem was a dirty main level pot. Cleaned it a couple of times and all is well. After fixing that a preamp tube for the rhythm channel died on one side. Replaced the tube and then the rhythm channel gain started cutting out. Cleaned all pots and checked voltages at all tubes, pre and power. Clean bill of health for now anyway. Glad is was simple but I should have figured that out sooner.

 

[jestaudio]

I feel a bit foolish. Problem was a dirty main level pot. Cleaned it a couple of times and all is well. After fixing that a preamp tube for the rhythm channel died on one side. Replaced the tube and then the rhythm channel gain started cutting out. Cleaned all pots and checked voltages at all tubes, pre and power. Clean bill of health for now anyway. Glad is was simple but I should have figured that out sooner.

Nice one mate, glad you got it sorted