Tube Biasing Tourmaster 4100

[dwfender]

So, I'm not new to Tube Amps playing wise but I am new to owning them and I have never replaced a set of tubes before. I use the tourmaster 4100 and they still have the stock 6l6R tubes in it. I had to ship the unit back to the manufacturer recently and UPS did an absolutely sh**ty job of shipping it back. The cooling fan was fractured and I'm pretty sure the power tubes had a good enough jolt to stop them from working correctly because the power on the amp has to be turned to 10 to get any sound worth listening to out of it. Regardless Egnater suggested I replace the tubes (which unfortunately has to be out of my dime) and I want to replace them with either the stock tubes or something that will give me a little higher gain without losing the crisp clean highs. Any information or reading that would be helpful would be awesome. Thanks in advance guys. I really want to get this amp back to where it was so I can start rockin the crap out of it again. It was pretty beautiful when I got it, just a hassle getting it back there now :/

 

[Rod]

Wow that sucks!!!...I own a 4100 Tourmaster head as well, and I've had a few issues with preamp tubes with that amp...It's an early one that came with GT JJ's, and they've been less than reliable over the past year. I suspect that the volume issue of yours is not the power tubes, but one or more of the preamp tubes, in fact, I'd almost guarentee it...The EH 5881's sound really good with that amp FWIW..and they're relatively cheap..With the preamp tubes, replace one at a time, and see if the amp comes to life...there's 7 of them in there...V6 and V5 are reverb and FX so it won't be those, but it could be any of the others...actually, start with V1.[look at the manual]...it's probably V1 or V2...If it's not the tubes, then I suspect UPS truly F'''d it up...I hope not,,. One more thing...DON"t waste your money on Groove Tubes!! get some tested High gain pre's from Doug's tubes or Euro Tubes ...an outfit like that...I like the High Gain.JJ ECC83's, [NOT the 803's], and Tung Sol and Mullard reissue 12AX7's...

 

[dwfender]

Not dismissing your idea just curious why you specifically think its the preamp tubes. I had spoken to egnater a few days after I had the amp shipped back and they were pretty certain that the problem was with the power tubes. Like I said I'm still new to all of it so I would love to read other peoples opinions before dumping a ton of money on tubes that don't need to be replaced. Also, I'm assuming preamp tubes need to be matched along with the power tubes? Is biasing the same process?

Ive been searching the internet for some straightforward summaries on replacing tubes and have yet to find anything worth its weight.

 

[Buckeyedog]

You should always have backup tubes just in case. Good news is no bias or anything on pre amp tubes. Just plug 'em in and play.

 

[Rod]

Not dismissing your idea just curious why you specifically think its the preamp tubes. I had spoken to egnater a few days after I had the amp shipped back and they were pretty certain that the problem was with the power tubes. Like I said I'm still new to all of it so I would love to read other peoples opinions before dumping a ton of money on tubes that don't need to be replaced. Also, I'm assuming preamp tubes need to be matched along with the power tubes? Is biasing the same process?

Ive been searching the internet for some straightforward summaries on replacing tubes and have yet to find anything worth its weight.

Well, if Egnater thinks it's power tubes, then it probably is......it's just that usually power tubes either work or don't work..And could all 4 power tubes be bad????..I highly doubt it....pre amp tubes are another story

 

[dwfender]

Just bumping this up. I'm still curious on the correct process to biasing the amp.

 

[jmgman69]

Just bumping this up. I'm still curious on the correct process to biasing the amp.

I just read the manual on the TM and it sounds pretty straight forward,if you have a meter and a good matched set of tubes ,drop them in and set the power grids to full power and go to town

 

[dwfender]

well that's my question actually. I know in theory how to do it.

Unplug the input, attach a cabinet, turn the amp on and check the voltage. My question is if I replace the tubes with a matched set of different tubes than the 6L6R does the voltage change accordingly and if so how do I determine what the correct voltage is.

 

[jmgman69]

well that's my question actually. I know in theory how to do it.

Unplug the input, attach a cabinet, turn the amp on and check the voltage. My question is if I replace the tubes with a matched set of different tubes than the 6L6R does the voltage change accordingly and if so how do I determine what the correct voltage is.

I would just bias it the range that is specified and then tweak to taste,seems like the same in the Mod series and no problemo with different tubes