Tube Noob needs just a little help.

[maddnotez]

I recently have been getting ready to test out different preamp tubes for my guitar amp.

The V1 slot is the only one I have messed with. It takes 12ax7, I had a JJ brand, now chinese brand and love the difference. Now I want more options

My question is this. wtf is a 12ax7



No really, I see there are different types and I want to be very safe with my amp.

Im looking on ebay and see 12ax7, 12bz7, 12ua7, ect, ect many many others.


What do they all have in common? They start with a 12 and end with a 7.


Does all the mumbo jumbo in between mean anything at all to me???

If I toss in a 12bz7 instead of the 12ax7 is that going to work for me?

Someone please explin this

 

[jerrydyer]

read anything you can get that Myles Rose has written. Google 12ax7'3 etc. lots of cool stuff. I like ruby HG for the first position if its high gain

 

[Anonymous]

which amp you referring to (im assuming one in your sig?)

http://thetubestore.com/gainfactor.html

that should help you a bit.

a lot of amps wont take different tubes than what they're spec'd out for by the manufacturer. other amps will take just about any 12xxx 9 pin pretube. you have to do some research to find out the differences between them... mostly it has to do with gain, plate current, plate voltage and plate dissipation related to guitar amps anyways.

http://www.audiomatica.com/tubes/

read this whole thread

http://forum.grailtone.com/viewtopic.ph ... ilit=12bz7

also, i've found "timbre wolf" over on the grail-tone forum (linked above) to be very knowledgeable about his tube lore...and i trust his ear..

a 12bz7 has basically double the gain of a 12ax7 on each side of the tube in parallel, but it also draws double the heater current, so, if you're not sure, i'd at least hold off until you find out..could be disasterous at most....

http://acapella.harmony-central.com/sho ... -for-12AX7

also, IME, i have a THD univalve, and it can use the 12bz7 in v1 or v2. it's a tad louder, noisier, and gainier....not truly worth the hassle it could end up costing you. i'd stick with 12ax7 (also known as ecc83 and 7025) or a 5751 for now...there's so many of them floating around you can get on the cheap that will keep you hmmming and ahhhhing over different tones literally for years, that you'd never even need to venture into the 12at7, 12au7, etc categories.
but, FWIW....welcome to the dragon chasing....if you decide to go down this path...i hope you have some money set aside for it...can get quite expensive.

 

[just42dave]

Ill send ya some good stuff tommorow to have fun with Cheers and enjoy the new found quest

 

[Anonymous]

some of my favorite current production tubes are the chinese 12ax7b's...otherwise known as the silver dragons.
the jjecc83s short plate is a good tube.

the sovtek 12ax7LPS is a great tube for the PI slot in any amp. some people will tell you that you should have a tube with matched triodes in the PI slot in your amp...other people say that it's hi-fi/hi-end tube stereo guy talk.

personally, i ordered a matched one and an unmatched one just to see...and it wasnt noticeably different between either in my tourmaster, univalve or 5150 amps...so id say, save the extra 5$ or so and dont get a matched PI tube...snake oil at this level in guitar amps...but, some others my disagree...to each his own.

a lot of people love the current production tung sols, i dont really love them after having a few in different slots in my amps over the past few years...i've just found better tubes.

you can find GE and RCA 12ax7 nos (new old stock) or vos (vintage old stock that are slightly used) that sound fine and will last forever. just be careful who you buy from....buyer beware rules apply here as well ESP on ebay...as you may know.

i have personal favorites that i keep an eye out for and keep a stash of, and you'll find yours too if you decide to explore this tube world...it'd kinda fun..but kinda like "how far you willing to go Micheal?" (kiefer sutherland-Lost boys)..hahah..if you know what i mean.