Replaced preamp tubes in Rectoverb combo - still having prob

[KuchDaddy]

Hello! I've been lurking here for a while, but this is my first post. Seems like some very cool people here. I have learned a lot!!

I play mostly acoustic, but my son is a metalhead and we recently purchased a Rectoverb series 1 combo from e-bay and we have been trying to troubleshoot a few issues with it.

The biggest issue it had was wacky microphonic squealing when using the efftects loop. The amp has (allegedly) brand new JJ tesla power tubes, but the preamp tubes were old, so we replaced all 5 of them with Electroharmonix 12AX7EH's with a balanced tube in the phase inverter position. That totally fixed the effects loop, which was nice, but we are still having other issues, which I still think might be tube related and I am wondering if we got some defective tubes.

The problems are:

1) VERY loud huming on the lead channel. This problem is intermittent and there seems to be no rhyme or reason as to when it happens.

2) General random noisiness, pops and crackles. Again this is intermittent and only on the lead channel, but seperate from the humming described above.

3) The reverb on the rhythm channel sounds like utter crap. Apparently the reverb tank didn't used to work at all until the previous owner replaced the reverb tank and cables with brand new ones. Now it works (I guess), but sounds bad.

I was wondering if any of you folks might have any ideas about what else to try before I take it to a shop. I guess it's possible that one or more of my new tubes are bad. Maybe I should have bought a spare to swap around.

Thanks in advance!!

 

[tele_jas]

Rectoverbs in general don't have a real deep, rich reverb... It's just kind of there, even turned up 100% it's not real "wet" sounding.

As for as the humming, when it's humming what happens when you unplug your guitar from the amp (take the cable out of the amp)?? Does it still hum, or does it go away?? If it goes away, it's the cable or guitar. Same with the cracking noise. If the noise is still there, try unplugging the reverb cables from inside the chassis and see if it may be the reverb tank or cables. If that isn't it, it try re-seating all the tubes or even blowing the sockets out with canned air when you have the tubes out and see if that doesn't help.

Another thing to consider, do you have any pedals running in front of the amp or in the loop?? Try not using the pedal/FX unit and see if that eliminates the problem..... Could be a noisy FX unit or the power supply for the pedal/unit humming.. (my $75 power supply that isn't supposed to hum, hums)?!?! So be sure to rule that out as well.

See if any of this helps and let us know what you find out??

 

[KuchDaddy]

Thanks tele_jas!

We've got a wah pedal in front of the amp and a delay pedal in the FX loop. Using either one of them alone is fine, but both at the same time...woah! Considerably more hum. They don't have to be in use at the same time to cause a double dose of hum, just powered up and plugged in. They are both being run from the same power supply. Maybe seperate power supplies or batteries in one of them will help.

I think we are still having some other issues, but that did help.

We'll check out some of the other things this evening, gotta go to work/school.....

Thanks again!

 

[Platypus]

Wah's will hum with a high gain amp like the rectoverb unless it's meant specifically for high gain applications (but hopefull not that bad) Daisy chaining the power like you are is also making things worse.

What kind of wah are you trying to use and what sort of pickup?

 

[KuchDaddy]

Platy,

It's a Dunlop Crybaby classic wah and a Boss digital delay. The guitar is an Ibanez RG Series with humbuckers, I think the are Demarzios.

Daisy chaining the power supplies is definitely contributing to the hum, but I think there are other issues as well.

Will do some more testing with effects removed and report back.

Thanks!!!!!!