The Perfect 12AX7


What is the prefect 12AX7? There are no perfect 12AX7s as tastes vary. It depends upon who is listening to the tube and to a degree the amp itself and the music itself. Some like distortion. Different 12AX7s vary in distortion and some are pleasing to the listener. An example of an amp liking a certain tube and being used on rock and roll is the upgraded Fisher 500B. Using K40Y-9 coupling caps that transforms the Fisher itself into a far superior sounding amp. Using cheap Chinese 12AX7s produces the most pleasing sound. Not perfect nor good on jazz or classical music it is extremely pleasing on rock and roll. But a close to perfect 12AX7 that is very low distortion and sounds great on all music exists IMO. My favorite tube was the Mullard 12AX7 long plate. Low distortion and accurate music reproduction. Also expensive at $200 each in NOS. I rarely buy used tubes. I got some JJ E83CC and was amazed how good the tube performed. It is a frame grid tube and only frame grid 12AX7 ever made. Frame grid is used on the tube input grid and is wound as perfectly spaced as possible. Frame grid tubes were last to appear in some types. The JJ sounds just like the Mullard long plate. The difference is it projects the sound into the room to the point the speakers disappear unlike the somewhat recessed sounding Mullard long plate. Like previously mentioned not everyone will like this tube as some audiophiles like distortion. The JJ E83CC was made about 15 years ago for only a few years. Stocks are getting low thus buy now. The best part is the tube costs only $29.

jimbennet

Siemens E88CC's are 6922 variant tubes not 12AX7 E83's. However, I use and have quite a collection of those Siemens tubes. They are my favorite of that variant.

Op, my first preamp was a Rouge RP-1. It came with JJ’s, hopefully not the model you are recommending, as IMHO, they sounded muddy. I quickly replaced them with an immediate improvement. Others had a similar experience. 
As a side note, the tubes that sounded best in my Rouge were the Brimars, followed by the Siemans. I actually did not like the Tele’s until I upgraded to the BHK. So again, very system dependent. 

I've been pretty happy with the Mullard CV4004 new issue. 

Anyone tried the Electro-Harmonix 7025EH?

gross +1. The poster that mentioned the CIFTE may be correct if that tube was silver plate triple mica. The CIFTE was a rebranded Mazda.