Single Recto problem!

[Renmauzo]

This is my first post here, but I was hoping that you guys could help me with something...

So, I was doing my usual rocking today and was messing with a riff... then I noticed that my volume was dropping. I kinda ignored it and kept going, then I started noticing that my gain was dropping as well.

I was looking at the knobs -- gain was almost at 1:00 on vintage mode and the sound that was coming out was low in volume and clean. So I tried the green channel. Low volume, high gain, barely any signal.

I turned it off and posted on Harmony Central, but I didn't really get any ideas other than to change the tubes. I went out and got a new set of Mesa EL34's and used an old set of preamp tubes that I knew already worked.

NO DICE

Still the same problem. Very little gain, very little volume. And now it sounds like there's a blanket over my speakers.

I'm not quite sure what to do other than send it to a tech, but I'd like some ideas as to what's wrong before I go doing anything expensive and drastic.

Any ideas?

 

[jbird]

Well 1st, I don't like that you did a complete tube replace without diagnosing which one could have been the culprit, and also don't like the idea of old pre-amp tubes! I'm sure your bias select is correct for the EL34's, and they are intended for your Mesa! What about a dying battery in your signal chain? Active pups? Effects?

 

[Platypus]

You just made more work for yourself

I'd say if I took a blind stab based on the info given that your issue is preamp tube related... specifically V1. I would put your original setup back together and follow the tube problem diagnosis portion of the manual to find your bad tube.