My 295 Stereo Poweramp has all the same power valves ???

[japster]

Hi,

just purchased a 295 Stereo poweramp and suspected all the power valves were the same so took the lid off and confirmed there are 8 x 6L6GC's in there.

Why have the 6CA7's been taken out ? Any ideas ?

Also if I wanted to put the 6CA7 or EL-34's back in do I need to re-bias it ?

Any help appreciated,

Thanks,

 

[talltxguy]

Congrats on the 295! 8)

Unless your poower amp has an adjustable bias mod, you do not have to bias it as the 295 was made to run EL34's & 6L6GC's at the same time. The inner sockets are supposed to run 6L6GC's & the outers run EL34's.

I'd call Mesa on the "running all 6L6GC's at the same time thing." I did hear of people doing this though, although I'm not quite sure why. If somebody wanted an Mesa power amp that ran all 6L6GC's, I don't see why he wouldn't go with the 2:90 as it has more features than the 295. To me, the 295's beauty is that it runs both types of tubes at the same time! But hey, to each his own.

 

[japster]

Hey,

thanks for the reply, also I think it's pretty weird cause whoever's worked on it before has put a replacement resistor across the base of (only) one of the EL34 sockets that is the wrong value, they have used a 2K2 instead of a 2K7 like all the other EL34 sockets have.

Not sure what the adjustable bias mod supposed to look like but I guess it involves some kind of potentiometer setup ?

Any help appreciated,

 

[talltxguy]

Ok, I was quite curious about this and called Mike at Boogie. He was a cool guy and quite helpful. Here's a summary of what he told me:

Yes, you can run all 6L6GC's in your 295. There is a catch, however. If you want to run all 6L6GC's, then run pretty cold 6L6GC's - like Mesa Reds or Yellows (GT 4's) - because the EL34 sockets would be rather warm for 6L6GC's.

By the way, the plate voltage for a 295 power amp is around 505 to 510.

Hope this helps!

 

[japster]

Hi,

that's mighty helpful of you thanks for that,

The valves that are in there at the moment are all the same, all General Electric 6L6GC - there is a part number or something stamped on the side that looks like IZ 188-5 or 1Z 188-5. I have no idea what this means. Any idea what these tubes are ?

Is there a tube reference guide anywhere ?

Thanks,

 

[talltxguy]

Hey, glad to help, Japster. The info helps me out too! 8)

Not sure what the numbers on your tubes mean though.

Anyway, the wife and kid were gone for a bit. I had some yellow Mesa 6L6GC's and popped them into the EL34 sockets. It sounded very good!

I plan on running all 6L6GC's on one side and use that for my soloing and clean stuff. I'll get me some warm JJ EL34's from Eurotubes and put them on the other side for the rhythm crunch and gritty cleanish stuff.

This amp is like 20 years old with all original parts and sounds terrific. Gotta love Mesa, man.

 

[japster]

Hey that's great,

I've just picked up some unused EL34's (4 off) for £40. So I'm going to try the opposite to you

I like your idea of running different sides of your 295. Best of both worlds eh :lol:

I'm totally amazed by the power of this thing, my band mates are not so impressed :mrgreen:

Oh BTW just bought a TC-Electronics G-System Limited, my dream rig is so close to completion now !

Cheers,

 

[japster]

Wow,

I can only assume that the 6L6's in the EL34 socket were worn out.

The new EL34's have made a terrific difference in the volume of the 295, now the volume control actually does something meaningful !

Makes me wonder if all the 6L6's are worn out, think I'll be changing them too.

These amps are incredibly loud even on Class A setting

 

[talltxguy]

Yeah, it's pretty loud, but it really does sound better the louder it goes!