I liked Raytheon or Westinghouse 12AT7's in mine.

I like the Tesla/JJ's alot in my Pro VLA. I liked the stock tubes the the Tesla's are a little smoother with more dimension. Very quiet, and the highs are better represented I think.

If you like the Mullards I may have to give them a try just for the heck of it. I've been a fan of the Tesla ECC83S for a lot of gear though and they do very well in my Pro VLA.

Raytheon 12DF7's, Westinghouse 12AX7's and Mullard 12AT7's. I need one more Pro MPA, too many tubes and not enough channels!

Looks like I'm going to have to try the Raytheon's and the Westinghouse tubes. Thanks guys.

Anyone try the GT Gold series tubes in their ART Pro series stuff yet? Cucco says they're great tubes but I haven't heard of anyone using them in a Pro VLA or MPA yet.

I knew this would happen, more choices! Hmm jonyoung has it right, must get more channels, Try them All! BWaHaHahaha.

Ooops, got my Raytheons and W'houses mixed up. The W'houses are the 12DF7's........but good luck finding any, I think I got the last 2 in existance.

I see some 12AU7's and 12AT7's suggested here. Using my limited understanding of these things, don't the AU's and AT tubes have a lot less gain than a 12AX7?

If so, is there sufficient overall gain in the preamplifier to make them useful without a corresponding increase in noise?

As it is, I've ordered a couple of the JJ Tesla ECC83S but am interested in understanding what the effects of these different specification tubes would be.

While I'm thinking about it the ART Pro MPA is specified with 12AX7A tubes. I'm substituting 12AX7's (without the "A" suffix).

Thanks,

Right. AT7's put out around 70% of the gain as AX's; and AU's around 50% I think. That's what helps change the tone so dramatically but at the same time reduces noise.

The Tesla/JJ's are 12AX7's, they're just called ECC83S's. So you're getting the same gain levels with them a 12AX7 gives you, but smoother and more balanced (IMO). More of an audiophile-type performance.

Thankx, that seems to echo what I've heard before.

Here's a good table on the differences between the aX7 type tubes.

http://www.vacuumtubes.com/12ax7.html

ECC83 is the European nomenclature for the 12AX7. 12AX7A can be used in parallel or series circuits, the 12AX7 in parallel filament series circuits only. Ohhh.

Hawkeye,

I haven't had any trouble using 12AX7's instead of 12AX7A's. Any AX7 category tube has a gain factor of 100, the DF7's and AT7's are 70. They're much easier to use on vocals due to the lower gain. It's almost impossible to drive one into distortion, as well as being warmer sounding.

Good info JY. I can see what you're saying about the 12AT7. To back up your story from the bass world, players who use Traynor's new YBA-200 all tube bass head are saying that replacing the 12AX7 with a 12AT7 gives them the opportunity to play cleaner and louder before the circuit distorts because of the lower gain.

With the ART Pro, I plan to experiment tracking Elec Bass Guitar and don't mind if I can get some overdrive on the sound, so for now I'll stay with 12AX7's. My Focusrite Trakmaster give me a pretty clean DI bass sound. I'll see if the ART can give me something different. I think it will.

Hmmmmmm.....I'm a bassplayer myself, got a "94 Trace Elliot combo rig with 2 10's, and a tube preamp. Gonna have to pop an AT7 in there! That's what I've been using for tracking, it has an XLR pre out on it.

Hawkeye, if you're talking about the ART Pro VLA then expect good results. It does a great job limiting bass.

Try cascading channel 1 into channel 2 for some even cooler effects; i.e., limit one channel and compress the next or whatever.

Hi Coyote Trax, I'm actually talking about the Pro MPA but I've got my eyes open to pick up a VLA also. It just seems like a natural pairing with the Pro MPA. That would give me two different flavours of mic pre and two different flavours of compressor.