#1
I recently thought about swapping tubes in my Peavey XXX combo amp (40 EFX version) and was thinking about changing the power tubes to EL34's instead of the standard 6L6's. Anyway, the guy at the local Sam Ash suggest I stick with 6L6's because I'm running through the XXX. I started looking around and found that the standard bias settings for the XXX was pretty off (head version though) and also something about different years of XXX production had something to do with another etc. Anyway.. do any of you know anything about this?

I bought a set of GT 6L6's and have yet to install them. It's to my understanding that I won't have to change anything switching from the stock tubes to the GT 6l6's.. can anyone confirm this? Thanks

sc0urge
Quote by Mascot
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#2
You still need to bias. I haven't heard anything in particular about XXXs having improper bias but I'd definitely believe it, knowing what the inside of one of those things looks like.
#3
How do you mean by..
Quote by Roc8995
...I'd definitely believe it, knowing what the inside of one of those things looks like.
?

http://www.eurotubes.com/euro-k.htm

About 2/3rds of the way down there's some stuff on the Peavey's. I'm entirely new to the biasing scene, but it's to my understanding that I'll either need some sort of tool (like the Ted Weber Bias Rite?) or get some professional help? But I thought I wouldn't need to bias if the tubes were rated the same? er.. what exactally does that mean by the way.. ''rated the same''? Sorry, I'm not too clear on much right now
Quote by Mascot
Calm down.

I'm not saying it again.
#5
Can anyone answer my other questions?
And also, I heard that the XXX 40 is an unbiased amp? Can anyone shed some light?
Thanks
Quote by Mascot
Calm down.

I'm not saying it again.
#6
The XXX isn't fixed bias?
Quote by Dave_Mc
I've had tube amps for a while now, but never actually had any go down on me
Quote by jj1565
maybe you're not saying the right things? an amp likes to know you care.





www.SanctityStudios.com
#7
In the tube cage of the XXX, there's a ''Bias Select'' switch between 6L6GC and EL34. I think this advocates the notion that this amp is fixed bias?

EDIT: I started warming up my amp again with the stock tubes and noticed (now that I've taken off the tube cage) that only one of the power tubes were working (glowing). I think that it's been like this since before.. but anyway, I turned the amp off and swapped the tubes with the pair of 6L6 GT's and let it warm up again. This time both tubes were working. However, when I took it off standby, I noticed a lot of static when I'm not physically touching any metal on the guitar. This was a problem before too but less severe before (I think it's because I only had one tube working?) Also, I attributed the excess static to bad tubes.. but I guess that's not the case? Improper grounding?
Quote by Mascot
Calm down.

I'm not saying it again.
Last edited by Sc0urge at May 8, 2008,
#8
Quote by Sc0urge
In the tube cage of the XXX, there's a ''Bias Select'' switch between 6L6GC and EL34. I think this advocates the notion that this amp is fixed bias?

EDIT: I started warming up my amp again with the stock tubes and noticed (now that I've taken off the tube cage) that only one of the power tubes were working (glowing). I think that it's been like this since before.. but anyway, I turned the amp off and swapped the tubes with the pair of 6L6 GT's and let it warm up again. This time both tubes were working. However, when I took it off standby, I noticed a lot of static when I'm not physically touching any metal on the guitar. This was a problem before too but less severe before (I think it's because I only had one tube working?) Also, I attributed the excess static to bad tubes.. but I guess that's not the case? Improper grounding?

Then yes, it's fixed bias like I thought it was and you shouldn't have to bias it, or rather, you can't bias it unless you have it modded.

Yes, the sound you hear is probably because it's being amplified more now that all the tubes are working. It's most likely bad grounding, my Strat did that and I went through and re-wired it and now all's well. Could be a cable as well, if you can, try different ones of each to rule something out at least
Quote by Dave_Mc
I've had tube amps for a while now, but never actually had any go down on me
Quote by jj1565
maybe you're not saying the right things? an amp likes to know you care.





www.SanctityStudios.com
#9
Quote by MatrixClaw
Then yes, it's fixed bias like I thought it was and you shouldn't have to bias it, or rather, you can't bias it unless you have it modded.

Yes, the sound you hear is probably because it's being amplified more now that all the tubes are working. It's most likely bad grounding, my Strat did that and I went through and re-wired it and now all's well. Could be a cable as well, if you can, try different ones of each to rule something out at least



Ok I know you're getting a lot of different advise on this but please listen to ME!! I've owned this amp for 5 years. I don't know how to bias an amp but i do know that if you change from el34's to 6l6's you SHOULD HAVE YOUR AMP BIASED!! The XXX is not a fixed bias amp. As far as which tubes you should run i suggest el34's. That's just my flavor though. choose wisely!! Just make sure you get it biased.
#10
Quote by impy11
The XXX is not a fixed bias amp.

Since when? If it really is like the TS says, you can't bias the amp unless you have it modded to be able to be manualy biased. All Peavey amps I've seen/used had a fixed bias where you just flip it to what tubes you want (if it offers that) and then pop the tubes in and that's it.

Also, this tread is 10 days old, why are you bumping this old of a thread? Well... at least it's not a year old like yesterday I guess.
Quote by Dave_Mc
I've had tube amps for a while now, but never actually had any go down on me
Quote by jj1565
maybe you're not saying the right things? an amp likes to know you care.





www.SanctityStudios.com