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A positive
01-09-2007, 02:27 AM
Hello everyone!!

I recently bought a Peavey XXX and I guess I'm quite happy.I say "quite" cause the sound seems to be grainy.Many told me that retubing and a good bias will do the job.Any opinions??

Thank you;)
rockon1
01-09-2007, 04:31 AM
If its new you obviously know the tubes are too. If not gets some new ones in there if your unsure of there condition. You can mess around with the bias knob in the back of the amp (behind the protective grill next to the PI tube) and see if you here a difference. I doubt it though. You may here a percieved difference in volume when you make the bias hotter as the amp will be a tiny bit louder. Counterclockwise is hotter. Factory setting at the bias test jacks (which isnt actually biasing it ) is 55 vdc for 6L6's and 42.5 for EL34's.

Heres something from Peavey tech on it.

http://home.comcast.net/~rcrimm/ultra.html
A positive
01-09-2007, 05:00 AM
Nice link thanks ;)
The 55vdc that is mentioned is referring to any brand of 6L6GC??
rockon1
01-09-2007, 05:38 PM
Nice link thanks ;)
The 55vdc that is mentioned is referring to any brand of 6L6GC??

Yep,its really not "biasing" the amp. Its just a setting Peavey deems safe for any 6L6. However for actual biasing you can get a probe from Weber (and others) and set it fairly easily seeing that it has an adjustment. I never bothered with my JSX. Heres a link.


https://taweber.powweb.com/biasrite/br_page.htm
Reeek
01-09-2007, 05:49 PM
I'm told many Peaveys, the 5150 head being one of them, are biased somewhat cold out of the factory so I'm not sure if that would be the case with the XXX but checking trhe bias would be a good starting point.
A positive
01-10-2007, 07:05 PM
I'm told many Peaveys, the 5150 head being one of them, are biased somewhat cold out of the factory so I'm not sure if that would be the case with the XXX but checking trhe bias would be a good starting point.

That's what I heard too.So -55 volts it's kinda cold you say isn't it??

One more thing...

Which hotter that -55 volts -50 or -60??
rockon1
01-10-2007, 07:52 PM
That's what I heard too.So -55 volts it's kinda cold you say isn't it??

One more thing...

Which hotter that -55 volts -50 or -60??


50 is hotter.Counterclockwise is hotter. Clockwise colder. On the 6L6 setting I believe you will go down to about 49vdc cranked fully counterclockwise which is as hot as it will get on the 6L6 setting. I ran my like that with 6L6's.
A positive
01-11-2007, 07:33 AM
50 is hotter.Counterclockwise is hotter. Clockwise colder. On the 6L6 setting I believe you will go down to about 49vdc cranked fully counterclockwise which is as hot as it will get on the 6L6 setting. I ran my like that with 6L6's.

If I set it at about 10 o' clock I got orange spots on the plates.

PS. 49v or -49v I got confused:crazy
rockon1
01-11-2007, 03:03 PM
If I set it at about 10 o' clock I got orange spots on the plates.

PS. 49v or -49v I got confused:crazy

Orange spots or redplating at 10 oclock? If its redplating thats hard to believe. Actually it would be the first time Ive heard of anybody redplating 6L6's with the bias pot setting even fully hot with this amp. However MAKE SURE your bias switch is on 6L6 if your using 6L6's. They CAN run too hot on the EL34 setting-possibly hot enough to redplate. As far as - 49 or 49 they should read 49 not -49 for example but if your leads are backwards it might read -.
A positive
01-11-2007, 05:50 PM
Orange spots or redplating at 10 oclock? If its redplating thats hard to believe. Actually it would be the first time Ive heard of anybody redplating 6L6's with the bias pot setting even fully hot with this amp. However MAKE SURE your bias switch is on 6L6 if your using 6L6's. They CAN run too hot on the EL34 setting-possibly hot enough to redplate. As far as - 49 or 49 they should read 49 not -49 for example but if your leads are backwards it might read -.


It seems to me more like orange spots.What's redplating exactly?I read that you cannot run your tubes with orange spots on the plate
rockon1
01-11-2007, 06:18 PM
It seems to me more like orange spots.What's redplating exactly?I read that you cannot run your tubes with orange spots on the plate


As long as it does not look like the pic in this thread your fine.

http://www.thegearpage.net/board/showthread.php?t=202508
A positive
01-11-2007, 07:23 PM
As long as it does not look like the pic in this thread your fine.

http://www.thegearpage.net/board/showthread.php?t=202508

In fact it looks like this but not so intense.On 10 o'clock as I said I can see the 1/4 of that in the picture on the top side of the plate and only in one tube of mine.