Dec 17, 2017 · The difference between a 12ax7 and a 12ax7a has to do with the way the heaters are wired. The 12ax7 can only be used in circuits where the heater circuit is wired in parallel, the 12ax7a can be used in series or parallel heater circuits. In modern gear you're unlikely to run into series heater circuits where your non-a 12ax7s won't work.

Jun 5, 2021 · Next, the expensive Mullard 12AX7 long plate is also very low distortion and can be a little polite, perhaps a little dark sounding, but ultra clear sounding. If your amp is a bit aggressive sounding the Mullard is a good choice vs a more 'polite' sounding tube amp that may prefer the GE 12AX7/7025.

Aug 23, 2021 · I like the JJ. 12AX7 and 12AT7. I use the 12ax7 in my headphone amp and the AT7 in a preamp. I should say have used the AT7.... its a spare, it was replaced by a Mullard 6201. I was actually surprised how good the JJ and re-pop Tungsol AT7 are... quiet , clean , super clear sounding. Two really good modern production tubes.

Jul 20, 2012 · I was researching vintage 12AX7 tubes, and a pattern emerged - over a variety of brands and countries of origin, "long plates" are more highly sought after and command a higher price. (Probably old news to tube fans.) My question - is there actually a physical characteristic of a longer plate that is beneficial for audio sound quality ?

Aug 3, 2018 · The Mullard 12AX7 long plate square getter is the best I ever heard. Seller stated Telefunken 803s are not as good at $1K+ each. A tube I thought is better than the 3rd place Mullard 12AX7 round plate are the Raytheon 5751 windmill getter. All are black plates. These windmill getter way outperform the Raytheon 12AX7 black plate by a mile!

Jan 1, 2019 · -3 sets of Matsushita 12AX7/12AU7-2 sets of Hitachi 7025/12AX7/12AU7-2 sets of TJ Full Music 12AX7/12AU7-1 set of RFT ECC83 plus 5 RFT 12AU7 (the RFT 12AX7/12AU7 were a present from a German neigbourgh, they came from his personal collection, he had literally TONS of them in NOS condition)-3 units of NEC 12AD7-1 set of NEC 12AX7/12AU7

Dec 15, 2020 · had a psvane 12ax7 t mk 2 in my Croft.To my ears ,the gold lion ,and the jj gold pin 12ax7 were better.But im using a Telefunken ecc83 now,and this works better than all for me .My Croft only uses one,12ax7,ecc83,so been able to roll a lot of new,and old nos tubes.Telefunken is best,folloewd my Amperex bugle boy,and mullard m1837 .

Feb 16, 2024 · In the end your wallet will be lighter, and the overall improvement compared the newer Russian made Genalex Gold Lion Gold Pin B759/ECC83/12AX7's will be a disappointment. The newer Genalex tubes coming out of the American owned Electro-Harmonix/New Sensor ExpoPul facility in Saratov, Russia manufacturers 2/3d's of the world's supply of tubes.

Jun 5, 2021 · Frankly, buy NOS GE 12AX7/7025 short plate for about $80 a pair (Brent Jessee) and never look back. GE 12AX7 without the 7025 are not likely the same tubes and definitely not ultra low noise as all 7025 have spiral wound low noise filaments. Here is the GE 12AX7/7025 short plate picture.

Sep 17, 2007 · There is a huge difference in gain (amplification factor) between the 12AX7/12AU7. The 12AX7 has approx. 5 times the gain of a 12AU7, therefore your choices are limited to high gain tubes from the 12AX7 family. You could try JAN GE 5751, these are very close to 12AX7, with slightly less gain but very good specs and they sound great.