LSS Problems w/5 watt channel: Already replaced 5y3

[ginsengnat]

Greetings,
So I have blown the 5y3 tube 3 times. Each time the amp seemed to 'fizzle out' with Channel 1 sounding more and more dirty and variable volume. Last night the same deal happened...this time the fuse and the tube blew. So I replaced both.

Problem is, channel one is still dirty sounding at the 5watt setting. Changing the 5y3 with a different one has not fixed the issue.

My questions:

What is up? I am supposed to play tonight and am trying to fix it before.

Is Mesa going to recall the LSS to fix this issue? Does anybody know?

Thanks for the help.
~nat

 

[vinnyk]

......or it will hang you out to dry in the middle of your gig.

I would call Mesa, and have them do some waranty work.It is probably a minor repair, but dosent sound like any fun!
Probably no recall though.
Good Luck

Vinnyk

 

[ginsengnat]

So,
I had put some groove-tubes into the EL-84 spots. They WORKED great, but after about 3 days I got the "fizzle fry" happen on the amp. Put the stock Mesa tubes back in and shazaam....Channel 1 is clean again.

I am confused. Anybody help?

I am the first to admit, the most I know about tubes is...well, I like the tone of amps with them. Other than that i am clueless...except I know the 5y3 blows all the time. That i don't like.

~nat

 

[speedy mcfeely]

call mesa. I have never blown a rec tube in mine. I use NOS preamp tubes and JJ power tubes with no issues. You should ask about changes made to components since inception, and of any known mods.

 

[fredster]

From what I've read here and talking to Mesa, the problem isn't with the LSS, it's the tubes. I haven't had a problem with the stock 5y3, but I bought a NOS one just in case. Haven't had any trouble so far...

 

[simonich]

I've blown two 5Y3s. I plan to get a couple NOS spares with my next power tube order.

There was a thread here on the board that suggested there is a mod Mesa will do to help fix the problem with the modern tubes. Do a search. I have not had the fix made, nor do I know anyone that has done so.

 

[NoGlassNoClass]

...Put the stock Mesa tubes back in and shazaam...

I'm gonna guess the problem is with the GT power tubes, perhaps drawing too much current and straining the rectifier circuit beyond its limits.

 

[carnivore]

I just got mine back yesterday from Mesa after having them do a mod that I am told will solve the problem. They covered it under warranty. I played it most of last night and so far so good. The mod did nothing at all to the tone. Time will tell if this totally fixes the 5Y3 problem. I still love this amp..

 

[212Mavguy]

There have been several threads within the last two months detailing the 5y3 problem with LSS. The current production 5y3 is operating too close to its limits in that amp and that is the problem. There are two solutions that are effective. One is to send in the amp to Mesa and have the mod done as Carnivore has, and the other is to pick up a vintage or new old stock 5v4 rectifier tube, they are inexpensive and common on ebay and have enough spare current capacity to do the job handily with no problems. 5v4 has same heater current, not significantly different voltage output, and more than enough output current to meet the needs in the LSS circuit without strain. Best of luck.

 

[ja22y]

I just got mine back yesterday from Mesa after having them do a mod that I am told will solve the problem. They covered it under warranty. I played it most of last night and so far so good. The mod did nothing at all to the tone. Time will tell if this totally fixes the 5Y3 problem. I still love this amp..

Carnivore,
can you tell us exactly what the mod was?

 

[carnivore]

They didn't give any specifics in the paperwork that they returned with the amp. The guy I spoke with on the phone at Mesa couldn't answer that question either but assured me that the guy that worked on these really knew his stuff. Sorry, I don't have any specific answers on this.