Monsta or any "techs". Dc-5 problem

[Dondante]

Ok started last night. I will play for a few minutes and my vol drops/fades about 90%, then after a few minutes... It fades back to "normal" power. Also notice bad feedback when my 808 is engaged on the clean chnl. Is this a power or pre-amp tube issue? I can tell you that tube in slot 4 when tapped I here a tap/light pop noise come from amp/speaker. The othe tubes do not do that. I'm gonna order new tubes soon as I just aquired this amp month or so back. But I have a cpl of spare old 12AX7's Layin around. Am I gonna waste time swappin one tube out at a time lol? Or is it power tube

Yes I bypassed pedals. Olives 2 guitars straight into the amp


Thanks ahead of time for the help.

 

[Dondante]

Nobody here has a single idea?

 

[espexp]

If you have a 12ax7 "layin around" replace V4 and see what happens. Feedback on the clean channel could mean a problem with V4.

 

[Dondante]

Thanks. That's exactly the one that I can hear a slight popping noise hen I tap it. The other tubes I don't here this at all.

 

[Monsta-Tone]

V1a & V4 are your clean channel tubes.
V1b (the other half of V1), V2, V3a are for your lead channel.

If the problem only occurs in channel 1, then replacing V1 or V4 should do the trick.

If the volume fluctuation is still there after you get rid of the feedback, then you probably have a power tube issue as well.
If you end up replacing the power tubes, it is usually a good idea to replace the Phase Inverter tube at the same time. V6, it is the preamp tube farthest away from the input jack.

 

[Dondante]

Sorry. Haven't been able to check back. Thanks monsta and others. It was the power tubes. Man does it sound better.

What do you suggest for the phase inverter amd loop tubes? Should I get clean as possible for those? I switched out the v4 and my feedback seems to be tamed.

Suggest a tube set-up for me. I really try and go for a "Trey/phish" tone mostly and umphreys mcgee style, which is all over the place. Lol. I haven't really got to dial into the lead channel. Mostly use pedals.

Set up: guitar>Korg tuner>bad H wah>maxon 808>Jekyll and Hyde>mxr super comp>mxr EQ>DC-5

in the loop is a EH nano small stone>visual sound H20

so talk pre-amp tube placement and recomend something. Only thing I have laying around are a couple of ecc81's. Which is why I asked if they are good door the loop and phase inverter positions.

Thanks
Chad

 

[Monsta-Tone]

A lot of guys here use an AT7 (ECC81) in V6. I don't like them at all in this amp!
Here is what I had in mine:
JJ High Gain set from Eurotubes in every spot but V4
V4 - NOS Siemens or GE out of an old Fender 75, so they were US tubes from the late 70's, early 80's.
Winged C or JJ 6L6's for power tubes.

 

[Dondante]

K. I guess what I'm looking for is as close to the mark IV on the dirt side as I can get haven't been able to dial it in as of yet. But probbly due to needing new tubes etc. Owned one several years ago and loved that amp. Just can't spend the $$ on it again. Shoulda never sold it.

 

[Monsta-Tone]

You might call Doug at Doug's Tubes too. I really liked what his set did for my DC-5, but hated what it did for the clean channel.
He's a bit of a douche too. I spent an hour or so on the phone with him and all he did was put down his competition. I didn't call to hear his opinion on Eurotubes, I called to get his opinion on his tubes and my amp. That kind of business might be the standard in New York, but I don't like it. I just wanted to tell him to shut the **** up and concentrate on his job!

If I were you, I would run a new thread just asking how to get as close to a Mark IV tone as possible with the DC. I honestly don't know if it's possible with a DC-5 unless you mod the lead channel a little to get more gain out of it.