REctoverb problems :( hum from hell1

[taproot]

I seem to be having some rectoverb problems. I own the head version, as well as a mesa 2x12 recto cab. The problem is that i get this wicked hum when i turn the standby on. Even if i completely cut off my guitar volume, i still hear it. It's worse on channel 2 (higain) and is heard on channel 1. It gets worse as the volume is turned up. Both the output and master. What should i do? I'm thinking its a preamp tube problem. I contacted mesa, asked a person and he said "it depends on how you run it" and i understand there will be some noise when you have ur guitar on, but i always thought there shouldn't be any noise when it was off.
I just replaced the powertubes, and i'm thinking i'm gonna need to replace all the preamp tubes to be on the safe side. I purchased it a few months ago at a store where the amp sat around for about 4-5 years in the store. I tried locating the problem tube, but couldn't seem to find it. I had a spare preamp tube lying around and tried to locate the bad one but no success.
Any help?
Also what are some good recommendations for hi-gain pre amp tubes with looowww microphonics ?? I was just looking at going for 1 mesa sp-ax7 for v1 position and 4 12ax7's for the other four, or just going for tungsol's 12ax7's. Thanks!
:0

 

[clutch71]

First off welcome to the the board.

Definitely try replacing the preamp tubes and see if that solves the problem. For trouble shooting I recommend starting with the tubes Mesa designed the amp around. IE Mesa Power tubes and the SPAX7 in V-1 Mesa 12AX7 V-2-5. You can always use extra preamp tubes.

If the amp was sitting and didn't receive much playing time, I would have recommended from day one that you give it extra time on stand by to allow the circuitry to warm up properly and then start the volume out low and slowly build. Also make sure your using a quality cable. May also want to try moving to a different outlet to see if that could be the problem.
If you have a bias pot ensure it's set properly and you speaker impedance matches your cab.

Once you've tried all that if the hum still persists, take it to an authorized Mesa tech and give it the old once over. After you've replaced the preamps and if the hum is present I wouldn't recommend playing it to see if the hum goes away.

Remember with hi gain amps there is going to a little hum as you drive the gain that will be more noticable as you drive the volume.

Good luck!

 

[chennie]

First of all: Check the reverb =)

Is the noise still there with the reverb switched off ? Use the footswitch and secondly test it by the reverb knob. If the noise is caused with the reverb, check the reverb wires from tank to chassis, use a bit of contact spray. Had this problem myself and have seen this problem before on this board

 

[taproot]

Yeah i'm going to replace the preamp tubes, it's definately not the reverb checked that. I realize there is going to always be hum, but i thought there wasn't supposed to hum even with the "guitar signal" cut off.
Thanks for the help.

 

[clutch71]

Just as an afterthought, did you try different cables? Different guitars?

A loose input jack on guitar will give you a similar effect. So could a bad cable.

 

[taproot]

i did check the cable, used several different ones, different guitar, even different speaker cable. I'm hoping its the tubes

 

[Juancito12]

Hi Taproot,

When I had issues with my 60's amps and found this page helpful:
http://www.geofex.com/ampdbug/hum.htm

I think the tubes are a good place to start after ruling out cables, guitar, and power source (outlet, other electronics nearby, ect).

 

[TheRazMeister]

I had the same problem but solved it by changing power tubes...which you've already done, so I'd definitely try changing pre-amp tubes. I will say this, the rectoverb is a VERY quiet hi-gain amp and noises are not normal.

I seem to be having some rectoverb problems. I own the head version, as well as a mesa 2x12 recto cab. The problem is that i get this wicked hum when i turn the standby on. Even if i completely cut off my guitar volume, i still hear it. It's worse on channel 2 (higain) and is heard on channel 1. It gets worse as the volume is turned up. Both the output and master. What should i do? I'm thinking its a preamp tube problem. I contacted mesa, asked a person and he said "it depends on how you run it" and i understand there will be some noise when you have ur guitar on, but i always thought there shouldn't be any noise when it was off.
I just replaced the powertubes, and i'm thinking i'm gonna need to replace all the preamp tubes to be on the safe side. I purchased it a few months ago at a store where the amp sat around for about 4-5 years in the store. I tried locating the problem tube, but couldn't seem to find it. I had a spare preamp tube lying around and tried to locate the bad one but no success.
Any help?
Also what are some good recommendations for hi-gain pre amp tubes with looowww microphonics ?? I was just looking at going for 1 mesa sp-ax7 for v1 position and 4 12ax7's for the other four, or just going for tungsol's 12ax7's. Thanks!
:0

 

[taproot]

Thanks for the replies, just ordered some 4 new 12ax7 and a spax7 last thursday, hopefully this fixes my problem!!

 

[taproot]

Just put in the new tubes, and still the same hum on the gain channel. But the clean channel is extremely better (hum wise, almost non existent). The overall sound is better though, but that **** background hum is killin me. So i'm thinkin its something internally with the amp? I had an extra tube so i switched it with the v2, then the v3, v4, and v5 hoping that would change since it was only on the high-gain channel. But nothing I'm planning on calling mesa and asking them tomorrow, hopefully i get a good answer.

 

[guitarmechanic]

Is it a hum like 60 cycle AC humming, or is it more like a rushing roaring noise?