I've been testing different 12AX7/ECC83 valves in my JTM50.
I had:
Mullard ECC83 i63
Tung Sol 12AX7 Reissue
Golden Dragon ECC83T
Electro Harmonix 12AX7
JJ ECC83 MG
JJ ECC803
I have to say, none of the current production valves were up to the standard of the Mullard. I'd find one which had a nice high end but then the low end would be bad and then vice versa. The Mullard seemed to have a high end roll off but not sound muddy in any way and broke up nicely on the bottom end.
The Golden Dragon ECC83T had a similar high end roll off but was slightly harsh sounding compared to the Mullard. Can't someone get that Blackburn factory re opened
12AX7/ECC83 - Amperex, EI, Siemens are all good candidates (along with Mullard) for Tonal performance. RCA & GE I've had good results with here. Nothing new compares imho.
For rectifiers the Sovtek Gz34.
For output EH 6CA7 (the big bottle ones)
Everything else is a shot in the dark.
Sadly.
I gave up on 803's - way too noisy or had Trotsky high end.
Wish I could go back to the 70's when Mullard were the general purpose/most commonly available valves & caps...
Sacriledge I know but a couple of no-name Chinese tubes I've tried are low noise & very high gain.
Most US made tubes from the old days are good.
Just don't put too much faith in who actually made them. A lot of horse trading went on back in the day. The sticky about identifying tubes helps.
WYSIWYG but not always.
Its just a bit sad that nothing in current production today can match the valves of yesteryear. I was very disappointed with the Golden Dragon ECC83T I must say. That was meant to be a top quality valve made to british standards. Bloody marketing.
I have to admit I haven't tried a Shugaung as I usually hear complaints of them having a fizzy top end. Not sure if thats true with the newest version as I know it has evolved over the years.
I'm not a huge fan of NOS as there is only a limited supply so when they run out we'll have to buy current production anyway.
I haven't experimented much with power valves. I've only tried TAD EL34B-STR (love these), JJ EL34 II and Groove Tubes EL34M.
Same with rectifier valves. Only tried the TAD GZ34. It only drops a few volts compared to 1N4007 diodes. Impressive.
You can still get russian military tubes reasonable. I nreally like the 6p3s-e.
As far as new production.I've had the best luck with Ruby branded tubes . they must do a good job testing them.
Some may argue the 6EU7 is not equivalent to 12AX7. I will argue that person is wrong. These are exact equivalents with different pin out. OK, there's a difference: you can't wire a 6EU7 for a 12V filament ;-}
Where am I going with this? I've had some luck on eBait with Mullard 6EU7's in the range of $20 and under, used, but plenty of remaining life. That's where I'm going with this. It's not exactly thinking outside the box.
Here's another. 6GK6 is EL84/6BQ5 with a different pin out. I bought a matched pair of NOS Sylvania from a reputable reseller (not eBait) for a reasonable price compared to EL84. He remarked that he didn't understand why the tube isn't more popular among those who roll their own.
I stuck a Mullard ECC83 i63 that I had on hand in V3 and it made a huge improvement. I've currently got a Tung Sol 12AX7 RI in V1 and JJ ECC803S in V2. It sounds awesome. I know V1 is claimed to make the biggest difference but I've always found V3 to make a bigger difference with the distortion characteristic.
The one thing most new valves have in common is they are all missing the lower midrange that the Mullards have. I think the new Mullard Reissues are supposed to have that lower midrange but we can't get them in the UK -_-.
There are some chemistry secrets that may have died with the last real tube engineers, but a major difference between the old stuff and the new was when old manufacture didn't come up to standards, it got binned. New manufacture rejects get sold.
