Pre-Amp (12AX7) Tube Comparison, in an M-Pulse 600

LowDown Hal · #1 07-19-2011, 06:58 AM

Can anyone point me to a discussion or chart or something which compares the tonal quality of the various 12AX7 tubes.

I needed a tube quick so simply went with the recommended Mesa-Boogie replacement. When I opened the amp, which I had purchased used, I found it had TungSol's.

Of course the store had numerous other varieties.

THANKS

iiipopes · #2 07-19-2011, 07:12 AM

Product Reviews

12AX7 Comparison Chart

fenderhutz · #3 07-19-2011, 07:17 AM

I always use JJ's for the simple reason they sound really good without a ton of noise and they are rugged. IMHO the best tube for the price.

JJ ECC83-S / 12AX7

http://thetubestore.com/12ax7review.html

LowDown Hal · #4 07-19-2011, 11:39 AM

THANKS

grendle · #5 07-19-2011, 04:15 PM

That chart is cool, but I don't agree with it much at all. Tubes are very subjective, but in no way would I ever call a 5751 thin and bright over a 12ax7, that's about comical. Take a look at the tube store or search for tube reviews on the net. There's a lot of info out there.

nashvillebill · #6 07-19-2011, 05:15 PM

A 5751 has 70 or 80% of the gain of a 12AX7, so technically I'd call it a different tube. Used in an application that is designed for its lower gain, there's no reason it should sound "thin and bright". Use it where a 12AX7 is really needed, I suppose the lower gain could be perceived as being thinner but that's really just a function of lower gain.

Otherwise, I take most of those tube comparison charts with a grain of salt.