Ei 12ax7 opinions

A

ampedup

Member
i'm new here and new to tube HiFi. i usually hang out at ax84, i've built 5 tube guitar amps. hifi is totally different, unlike a guitar amp, you don't want distortion. i will be getting a fisher 500b soon and i've been reading everything on here about fishers to educate myself, lot's of good info. going to be ordering some 12ax7s and was curious what you guys think of Ei's. they seem to be bad for high gain guitar amps due to microphonic problems, but sellers seem to recomend them for hifi. whats the concensus?
 
Register to hide this ad
Yeh guitar amps can get pretty bouncy. I've never tried the EIs, but if your set on new production, I've used EH (Electro-Harmonix) in Fisher stuff with good results. 12AX7's are very system dependent. Most people do a lot of experimenting to find just the right tone. Welcome Aboard :thmbsp: Jay
 
i would like RCAs too but they're too expensive in the quantity i need. i like the EH tubes for guitar and was leaning towards those but thought the Ei might be better for hifi. it seems like people here like the jj 7591 so i'll probably get those too.
 
Yeh, I haven't tried the JJ 7591s yet, but I need to. Be sure to let us know your opinions if you do. My opinion on the EH x7 is it's a nice tube for the dough. They seem very quiet and sound nice. Maybe someone will chime in on the EI's. BTW I do have some EI KT 90s that I like, but have heard they were having quality issues. Here's a good site to check out http://pages.prodigy.net/jimmcshane/ Pretty much the straight poop from a well respected guy.
 
ampedup said:
. . .i will be getting a fisher 500b soon and i've been reading everything on here about fishers to educate myself, lot's of good info. going to be ordering some 12ax7s and was curious what you guys think of Ei's. they seem to be bad for high gain guitar amps due to microphonic problems, but sellers seem to recomend them for hifi. whats the concensus?
Click to expand...

Personally, I'd avoid the Ei's like the plague. Too dark, too harmonic, easily overdriven. Definitely not for me.

I like the new JJ ECC803S/12AX7 for a close to vintage Tele's sound. They can be driven a bit on the hard side before breakup (not as hard as the Tele ECC83), and the highs are fairly smooth and clean.

Electro Harmonix 12AX7-EH also seems to work well.

These won't break the bank replacing the older 12AX7's, and the performance is good. Spend the extra $ to get them balanced and matched.

Stay away from any newly manufactured long plates. They're generally noisier and have more microphonic issues than most short plates.

If you're ready to spend $$$$ on NOS or used Telefunkens, Mullards, Jan Philips, RCA, GE, Tung-Sols, etc; you may get tubes that will last longer, and may sound better. However, 'sound better' is a highly subjective issue.

. . Falcon
 
jaymanaa said:
Yeh, I haven't tried the JJ 7591s yet, but I need to. Be sure to let us know your opinions if you do. My opinion on the EH x7 is it's a nice tube for the dough. They seem very quiet and sound nice. Maybe someone will chime in on the EI's. BTW I do have some EI KT 90s that I like, but have heard they were having quality issues. Here's a good site to check out http://pages.prodigy.net/jimmcshane/ Pretty much the straight poop from a well respected guy.
Click to expand...
did you see his comments about the 7591:
"Important note! There have been some cases where the new production 7591A tubes (EH and JJ) have had trouble
in circuits using a very high value grid resistor - as vintage Scotts, Fishers, and others do. The best solution is to change
all the grid resistors to 150K (from the old value over 300K - sometimes they even exceed the old RCA tube manual
recommendation!), and change the coupling caps to .1 uf or .22 uf. I stock all the parts you need, the parts cost is only
$10.00 to $15.00 per amp, depending on the coupling cap value and voltage."

i haven't heard about the grid resistor thing before.
 
EI 12AX7s are my favorite new-stock 12AX7s. To me these sound a whole lot like the old Amperex 12ax7s. But I do not make my judgments based on microphonics, so they may stink in this regard; I don't know.
 
goldear said:
EI 12AX7s are my favorite new-stock 12AX7s. To me these sound a whole lot like the old Amperex 12ax7s. But I do not make my judgments based on microphonics, so they may stink in this regard; I don't know.
Click to expand...

The folks at Manley Labs also seem to love the Ei line, 12AX7's, EL84's, KT90's. These are in their hi-fi line of audio.

I guess if you have the right circuit for them, they'll work.

. . Falcon
 
ampedup said:
did you see his comments about the 7591:
"Important note! There have been some cases where the new production 7591A tubes (EH and JJ) have had trouble
in circuits using a very high value grid resistor - as vintage Scotts, Fishers, and others do. The best solution is to change
all the grid resistors to 150K (from the old value over 300K - sometimes they even exceed the old RCA tube manual
recommendation!), and change the coupling caps to .1 uf or .22 uf. I stock all the parts you need, the parts cost is only
$10.00 to $15.00 per amp, depending on the coupling cap value and voltage."

i haven't heard about the grid resistor thing before.
Click to expand...

I've had no issues with the JJ 7591S tubes in my restored Scott LK-72A, which uses 330k grid resistors. But, I also added two pots to control the grid voltage (for properly setting the bias).

The LK-72A already uses 0.1uF coupling caps.

. . Falcon
 
Jim Mcshane has the new reissue tung-sol 12ax7. I use them in my crossover and like them quite a bit.
 
In my amp I have the EI 12ax7 and 12au7 and they have worked just fine, no issues to report, in the pre i have the RCA Black Plates, all in all I love the sound!!!
 
The only new production 12AX7 that I tried and liked were the EI's, for whatever that is worth.
 
I am particularly fond the entire Ei Elite line of tubes, especially the gold-pin EL84's, but also their preamp tubes. They do seem to require more burn-in time than NOS tubes, for some reason (I don't know why). So I guess my point is: yes, that is a good choice.

I've also heard good things about the Sovtek 12AX7LPS and the Tung Sol reissue from New Sensor?
 
Dusty Chalk said:
I've also heard good things about the Sovtek 12AX7LPS and the Tung Sol reissue from New Sensor?
Click to expand...
I've tried the Sovtek 12ax7LPS, and though it sounded OK (but not fantastic); and it got its butt kicked by the EI 12ax7s in my system. I have not yet tried the new Tungsols; but I have been meaning to do so one of these days...
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom