tube amp biasing/matching question

[firebirdVII]

Well the forum disclaimer never said anything about the amp being guitar related , and I tried posting in the sound room...

But the gyst of it is as follows.

I have a small headphone tube amp which runs two channels each with one preamp tube and two power tubes. If I want to retube it, do I need to get matched quads, or will two sets of matched pairs work?

Also, do preamp tubes need to be matched? Lastly, these are all miniature tubes, but is it possible that I will need to change the biasing with this thing?

I do have schematics, and I believe that the power tubes are in push pull configuration.

 

[Zerberus]

Re: tube amp biasing/matching question

Power tubes should be bought and installed as a matched set. A Rebias will often be in order here.

Preamp tubes never really NEED to be changed at all, but can be for a different tone. Rebiasing is not necessary here.

 

[Boogie Bill]

Re: tube amp biasing/matching question

Well, preamp tubes DO go bad, they can get microphonic, noisy, gassy--or suffer from mechanical damage and vibration.

If the amp is true stereo two channel, then two sets of two might be fine. But, it really depends on the amp's design. I'd advise you to have it professionally serviced with matched tubes correctly biased.

The preamp tubes do not need to be biased. Some audiophiles like to use a "matched and balanced" preamp tube set, that are specially selected for low noise. This may or may not be necessary with your amp.

Take a look at thetubestore.com site, and see what they offer.

Bill

 

[Duke of Metal]

Re: tube amp biasing/matching question

+1 to what both of Boogie Bill & Zerberus.

Depending on what you have for an amp.. if your amp uses 4 power tubes, then I'd get a matched Quad.. if your using a poweramp with 2 channels and each channel uses 2 power tubes, then Matched pairs is the way to go.

Ofcourse like Boogie Bill said, preamp tubes will end being replaced some point of time from going microphonic or the one changes on them.

Also.. I noticed your on the american side. I'd suggest ordering from Doug @ www.dougstubes.com. It'll be cheaper on the shipping and he has excellent service.

thetubestore.com is a canadian shop and to be honest, I've heard some stories from very un-satisfied customers.


Good luck!

 

[marvar]

Re: tube amp biasing/matching question

1
Also.. I noticed your on the american side. I'd suggest ordering from Doug @ www.dougstubes.com. It'll be cheaper on the shipping and he has excellent service.

thetubestore.com is a canadian shop and to be honest, I've heard some stories from very un-satisfied customers.


Good luck!

'I've heard nothing but good things about Dougs- I've heard lots of bad things about Tubestore.

 

[firebirdVII]

Re: tube amp biasing/matching question

Thanks, I actually have an amp that is running some pretty odd little tubes. The reason that I asked was because I noticed that I could get some NOS tubes from companies like Westinghouse, RCA and tung-sol for $4 each.

I also recently found a store that both sells them and matches free.

Zerb (can I call you that?), that was the first question I was wondering about, because being able to play with tone is fun, so why not if you can for relatively cheap?

Thanks again.

 

[Kommerzbassist]

Re: tube amp biasing/matching question

Zerb (can I call you that?), that was the first question I was wondering about, because being able to play with tone is fun, so why not if you can for relatively cheap?

HOLY CRAP you shouldn't have called him like that!!!!! He always gets mad when someone does... like... really mad! OTOH, he is also quite mad even when noone does call him like that. So you should be save. Whatev.

Seriously, I'd say if you can play around with the preamp tubes, do it. But listen to them for a little while after changing so you get used to the sound a bit and then decide whether you like them or not.