Jeff or Bruce: Tourmaster 4212 Power Tubes Question

[Len Rabinowitz]

Guys:

What power tubes can you put in the Tourmaster and still get the power scaling?

The manual says that only 5881/6L6/KT66 types will work in there but I don't recall the manual saying anything about only the 5881's having the power scaling, or saying anything about tubes and the power scaling at all.

Eric (on this board) seems to say that you can put any power tube in there, but only 5881's will give you the power scaling. Here's what he said:

"Len. You can put any tube in the Tourmaster but you will not be able to use the power scaling. The only tubes that work w/ the power scaling are 5881s. I distinctly remember Jeff saying that.

So if you want to try another type of tubes, you would need to set the power scaling at full for every channel. If you use things like KT66, KT77, EL34s, 6550s, KT88s, you'll need to set the power scalling at full.

Ask Jeff / Bruce if KT66s will work w/ power scaling. I know KT66s are acceptable to use in a lot of 6L6 Fender amps as an alternative, but I'm not sure they will work as expected w/ power scaling. Only Jeff / Bruce would know that."

So, what's up with that?

Thanks!

PS: I currently have GT 6L6's in there and I have been assuming that the power scaling works with those.

 

[Len Rabinowitz]

bump

 

[Len Rabinowitz]

Bump- I actually need an answer to this!

 

[jmgman69]

Their busy I guess

 

[Len Rabinowitz]

I guess so!

I assume taht any power tube that is listed in the manual works with the power scaling, but that doesn't seem to be what Eric is saying. He is usually pretty spot on, but I can't think he is correct here. Let's see if we can get the big honchos to weigh in.

 

[aeroic]

I guess so!

I assume taht any power tube that is listed in the manual works with the power scaling, but that doesn't seem to be what Eric is saying. He is usually pretty spot on, but I can't think he is correct here. Let's see if we can get the big honchos to weigh in.

Yes...that is correct Len. Any power tube that is listed works with power scaling. If you wanted to run 6550s or EL34s...or whatever...you couldn't use power scaling.

I know Jeff said that for sure.

 

[aeroic]

Len:

viewtopic.php?f=26&t=33843&p=399571&hilit=tourmaster+6550#p399571

Yes you can use any tube. The power grid becomes on 50 or 100 watts and nothing else.

We went for a smoother and bigger low end with the CL 80. It seems to be the magic speaker with this combo.

The pre amp tube layout is on page 17 or 18 of the manual I believe.

There's your answer.

You can only do 50 or 100 watt w/ tubes other than 5881s...etc.

Eric

 

[Len Rabinowitz]

That answers it for sure. Thanks for your help!

 

[Anonymous]

Len
did you ever try this? what did you use?

i actually have been told by Bruce not to use anything in there other than 6L6's (as per my post on this before) due to the filament draw being too much for the power transformer to handle.
im just sticking with 6L6's for now.

 

[Len Rabinowitz]

6L6's. I went with using only what the manual recommends as I want the full capacity of the power scaling.

 

[Anonymous]

have you noticed how at full power, the 50 watt setting responds differently than half power 50 watt setting?

most noticeable on ch3. i actually LOVE ch 3 on halfpower/50 watt mode.

and channel 4 on full power 10 watt

the cleans both sound REALLY good at straight up full power, and half power. but i dont care for them really in the other settings

i keep my bias at idle around 132 also.