Replacing Tourmaster Tubes

[dwfender]

So my Tourmaster 4100 tubes finally went on me. Started to get a lot of grit on the clean channel so I decided I want to replace. I went to Doug's Tubes and started looking around and figured out some tubes I want but I have a question. The tubes are 5881/6l6 and 12ax7/ecc83's. So regardless of biasing you can only replace with variations on those original types correct? I couldn't put a set of El34's in and rebias the amp to the right mV's?

 

[Len Rabinowitz]

Been a lot of discussion ion this.

*You can put in EL34's and re-bias but you will lose the power scaling!* If you like the adjustable power you have to use what they recommend. If you don't care about it, set it all on full blast, and put in whatever you want for power tubes as long as you bias them properly.

You can use any 12AX7 you like for pre-amp tubes.

 

[dwfender]

So in other words, Power tubes are interchangeable as long as you rebias and preamp tubes are specific to the type specificed for the map

 

[Len Rabinowitz]

Actually, I am not sure you have understood me. Let me try to be clear:

You can put any pre amp tube in any pre amp tube slot. They have to be a 12AX7, that's all. Some types of tubes may be better suited to different functions, but any 12AX7 will work in any pre-amp tube slot.

The power tubes are a little different. If you want the power scaling, that has to be of the 5881/6L6/KT88 type, like it says in the manual. If you don't care about the power scaling, set it to full and throw anything in there.

Any power tube would have to be biased properly regardless.

 

[aeroic]

Actually, I am not sure you have understood me. Let me try to be clear:

You can put any pre amp tube in any pre amp tube slot. They have to be a 12AX7, that's all. Some types of tubes may be better suited to different functions, but any 12AX7 will work in any pre-amp tube slot.

The power tubes are a little different. If you want the power scaling, that has to be of the 5881/6L6/KT88 type, like it says in the manual. If you don't care about the power scaling, set it to full and throw anything in there.

Any power tube would have to be biased properly regardless.

Just to be clear too...You can use a 12ax7, or lower gain tube if you like also. Like a 5751...or a 12AT7 if you want to get more headroom in the amp. Some people (like myself) like a Jan Philips 5751 in my Twin, DLX, VX, etc modules because it has a cool vibe to it, but it's not a standard "12ax7" in terms of gain. Same reason some like the 7025 preamp tubes also. As long as it's pinned out like a 12ax7, you can put any brand of 12ax7...or go to a 5751 or 12at7 as an example of alternatives. YMMV on those swaps though. Some sound awesome...and some sound like shit!

Eric