Newb - Greetings

[chumpchange]

hi fellas,

i'm a recent new owner of a DC-3 which i'm enjoying thoroughly(after years of lugging around a marshall .5 stack)

one thing i'm noticing though is that at different times my volume is degrading with a lot of trash in the signal.
the po was under the impression that these are the original tubes which i have no problem putting new tubes if that will correct the issue but it seems to span across both channels while its doing it which makes me curious if tubes is/isn't the issue.

i've looked thru a couple of related threads but saw a lot of different situations/solutions.

also, i noticed that sweetwater.com sells mesa tubes. any input before dropping coin would be appreciated.

TIA,
mg

 

[94Tremoverb]

The tube use is quite complicated in this amp - a bad tube could cause this sort of problem on one, the other or both channels depending on which one has gone.

Several of the tubes operate on both channels - all the power tubes (the tall ones, EL84/6BQ5s), and preamp 12AX7 tubes V6 (the Phase Inverter), V3B (the preamp tubes contain two half-tubes, which operate independently - a fault in one half won't necessarily affect the other), and V5 which is the reverb drive/recovery tube. V1 is shared between both channels, one half per channel; V4 is for the rhythm channel only, and the lead channel uses V2 and the remaining half of V3. The tubes V1-V6 are numbered in order starting at the end nearest the input jack.

If you're still with all that ( ), a noise problem with changes in volume on both channels is most likely to be power tubes or the phase inverter. If the amp is old, it's most likely that the power tubes do need changing, since they do wear out faster than the preamp tubes - but *don't* throw out the old ones just yet, since they may be fine, especially if they are original US-made tubes and the amp hasn't been used all that much - tube life is in hours of use, not calendar age.

Change the power tubes first, and if that fixes it you're done. If not, you first need only one spare 12AX7 - try replacing the phase inverter first, and if that doesn't fix it, try V3. A spare set of power tubes and a preamp tube is always worth having, so even if it turns out to be only one of these, you haven't wasted your money.

Or, it may be nothing to do with the tubes - these amps are getting old enough that electrolytic cap failures are becoming more common. But try changing at least the power tubes and one of more preamp tubes first, since that's something you can do yourself. Changing the preamp tubes is quite tricky by the way - it's easiest if you turn the amp upside down so you can see into the sockets to get the pins lined up right.

 

[chumpchange]

good info!

is there any tip on handling the tubes or a way to make sure they're completely discharged?

powered off and unplugged granted.