Ceriatone Overtone problem?

[jads57]

Hi, I just bought a used Ceriatone Overton Special(50watt) from a freind. But the clean channel seems to breaking up, even when I turn down the pre, and especially when I run the master at full volume. I checked all of the preamp tubes, and I am running fairly low output humbuckers and mini-hums into the normal channel. Any ideas? Thanks in advance

[Structo]

Well aside from V1 being bad I wouldn't have a clue.

Try swapping V2 with V1 and see if it still does it.

[jads57]

Tried that already, thanks though.

[Bob-I]

It could be a bias issue or a power tube problem.

[jads57]

Thanks, I`m going to check thepower tubes out .

[nickm57]

Apart from checking voltages and bias.

Plug directly into the power amp in. Through some sort of clean preamp/pedal to act as a buffer/ or come out of your preamp into a known good amp. Track down the origin first.

I noticed on my build that lead dress on V1 is sensitive. Check the coax wires from the relays, pots and input jacks

nick

[Bob-I]

I noticed on my build that lead dress on V1 is sensitive. Check the coax wires from the relays, pots and input jacks

nick

That is a good point. Lead dress on these amps is critical. Check out the Dumble pics in the files section and compare.

[jads57]

Thanks everyone for the info. I ended up replacing the power tubes w/ a spare set of new 6L6GC Mesa/Boogies I had, and biased them around 23mv . I also ended up running the pre at around 6-7 range and the master at around 4-6 range. I`ev noticed that the master comes on really quickly at around 2-3 and doesn`t have much increase in volume until around 9-10. Is this common on these amps?

[Structo]

23ma is pretty low on 6L6GC's.

I bias mine around 32ma.

But most say that these amps sound better a little on the cold side.

28-32ma.

The master doesn't sound right.

If you have the preamp volume up, say around 12 noon, the master should have a great deal of control from 2 on up.

[jads57]

Thanks Structo(aka Tom) I ended up rebiasing the tubes to 30ma, and swapping out the first preamp tube JJ ECC-83 w/ a VHT 12AX7 (probably chinese) Sounds a lot better now! Again, thanks to everyone for their help.

[Structo]

Right on!
Glad you have it working right.

I find I really like the Chinese 12AX7's in my D'Lite 44 (6L6GC) amp.

They have a certain grind I like a lot.

Also quite a few ODS clone owners have said they like them as well.

[jads57]

Ended up taking my amp to a local tech so hecould bias it proprely and install the newer Tweaked Mods ( J Zucker) Should have it back in a couple of weeks!