Looks like I'll be calling Mesa Monday

[SoCalSteve]

My Ace is only 4 months old and I've already had two preamp tubes go bad. Now, when I use the Spongy power setting the volume drops very, very low.

 

[SoCalSteve]

The first failure was a stock tube in V1. I replaced it with a GT12AX-7M that went bad last week. Friday night I replaced all the preamp tubes, except V4 (the FX loop). I played the amp after the tube change and it was fine. When I went to play it Saturday night the problem was there.

I've never had to replace tubes in an amp this frequently, that's why these problems concern me.

 

[cant play pool with a rop]

Who have you been gettin from? I've had reliability issues with the GT12ax7M and Tungsols. Maybe a bad batch?

 

[SoCalSteve]

Wel, the tube failures don't concern me as much as the huge volume drop now in Spongy power mode. I'm just wondering if the two are related somehow to a bigger problem inside the amp.

 

[jbird]

Sorta sounds like an incoming voltage problem! Have you tried switching rectifiers? Namely, from Tube to Diodes? Or just thought about replacing the rectifier tube?

 

[SoCalSteve]

Yeah, it does it in rectifier and diode modes. As for replacing the rectifier tube, if I'm gonna be replacing tubes every couple of months, something isn't right and it will be too expensive to keep the amp.

 

[SoCalSteve]

Update: Talking to Mesa, it seems some tubes "sponge out" too much in Spongy mode in V3 and V4. I put the stock tube back in V3 and (I left the stock one in V4) problem solved. See my longer post in my Stiletto Ace tubes thread in the tube area if you will.

Man, this amp sounds great!

 

[Platypus]

Congrats, the Ace is a sweet amplifier 8)