4212 Tubes and Speakers

Len Rabinowitz

Len Rabinowitz

New member
Couple of questions for the experts out there.

1. I was just reading the 4212 manual on tube biasing. It only references biasing on the power tubes. Am I reading that right? Can try new pre-amp tubes in it without re-biasing it? Not ready to get into fooling around with the biasing yet.

2. Any thoughts on removing the back speaker panel for an open back sound? I thought I read somewhere not to do it but I couldn't find that in the manual.

Thanks! :confused: :rock:
 
Swap away with pre amp tubes with no need for bias. That's half the fun of a tube amp!! Beware........it's an addiction though!!

Bruce makes his amps easy to bias though, so don't be afraid to venture into that either.
 
That's what I thought- It's the power amp tubes not the pre-amp.

I will get into biasing but not now. Where and what kind of voltage meter should I get?

Any suggestions for cool pre-amp tubes? I am into pretty much any kind of guitar tone from clean to distorted, except for maybe really heavy metal tones- too bassy and dark for me.

Any thoughts on the other question about the speaker cab back?
 
Go to dougstubes.com and search around. He has I think an assortment kit of like 4 of the basic tube brands. I think most of us really like the Tung Sol Reissue as well as chinese. Some like the JJ's, but many think they are a bit fuzzy and dark. You can try Sovtek LPS, Tung Sol, Chinese, EH and just the standard Sovteks. Those are the basic tubes really that most seem to like in one way or another.

I personally wouldn't remove the back panel, unless it was designed that way......to like remove the top half or something. If it's just one big panel in the back, I don't think that would work very well.

Oh, and you can just get a digital multi meter at like Lowe's or Radio Shack........$20 - $30 will do it. You don't need a real fancy one.
 
oh yea..

i have been thinking on jumping on the tube testing ....

If I am running my 4100, do I need matched quads, or will the Matched pairs work if I run in 50 watt mode?

I am assuming singles is a really dumb way to go the way I understand how the power tubes work.... and having 2 types of power tubes in there period at the same time is bad.
 
Buckeyedog":1hvyhk0o said:
Go to dougstubes.com and search around. He has I think an assortment kit of like 4 of the basic tube brands. I think most of us really like the Tung Sol Reissue as well as chinese.

Thanks! I think some of my original pre-amp tubes haver gone bad. John at Egnater is sending me some new ones- still under warranty. Once those are in I may play around a bit.

Some like the JJ's, but many think they are a bit fuzzy and dark.

Fuzzy and dark wouldn't work for me. I like snap. After 5 happy years with a Mesa, one reason I got rid of it was that it was just a little too dark sounding.

You can try Sovtek LPS, Tung Sol, Chinese, EH and just the standard Sovteks. Those are the basic tubes really that most seem to like in one way or another.

I personally wouldn't remove the back panel, unless it was designed that way......to like remove the top half or something. If it's just one big panel in the back, I don't think that would work very well.

It is removable- Just unscrew it.

Oh, and you can just get a digital multi meter at like Lowe's or Radio Shack........$20 - $30 will do it. You don't need a real fancy one.
Click to expand...

Thanks!
 
blueburl":1bd8wts8 said:
oh yea..

i have been thinking on jumping on the tube testing ....

If I am running my 4100, do I need matched quads, or will the Matched pairs work if I run in 50 watt mode?

I am assuming singles is a really dumb way to go the way I understand how the power tubes work.... and having 2 types of power tubes in there period at the same time is bad.
Click to expand...

If I recall the manual, Egnater recommends matched quartets. Matched pairs might do it, but then you can't be sure what would happen if you ever ran in 100 watt mode. Singletons is definitely not good!

:thumbsup:
 
I wish there was a way to wire the power grid to fire 2 or the other 2.. not 2 or all 4 (there may be)

then you could change tubes on the fly by constricting the amp to 50 watts
 
I changed the pre amp tubes out in my 4212 several months ago and if memory serves the fan is attached to the back plate. You take the back plate off and you'd have to remove the fan and attach it some where else to the amp or not use it at all. I think Bruce designs great amps and I'm sure that fan is there for a good reason and I wouldn't really be willing to run the amp without it....just my thoughts
 
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