Can You Spot a Vintage Mullard 12AX7?

[whatdisay]

Hello, all, just recently remembered about this forum and thought I'd post something I did for another guitar forum I'm on.

I recorded a loop using my Gibson LP Special with P90s then played the loop through my '78 Park (Marshall) 50W Bass head using 6 different 12AX7 tubes--some that were stock new tubes pulled from amps, two that were 50s Mullard long-plates that I paid a nice $$ for. Here are the tubes (not in order of the track numbers):

(1) JJ
(2) EHX
(3) 1959 Mullard Blackburn long plate
(4) 1958 Mullard long plate
(5) GT
(6) ARS

Here are the clips, if you'd like to test your ears!

https://soundcloud.com/whatdisay/sets/1 ... al_sharing

[Stevem]

To me this is a flawed test / comparison because we, and or you also do not know how they test for Gm.

I would in the least want to see how there cathode idle voltage changed from tube to tube!

[whatdisay]

To me this is a flawed test / comparison because we, and or you also do not know how they test for Gm.

I would in the least want to see how there cathode idle voltage changed from tube to tube!

Ok.

Do you have a guess as to which clips have the ‘50s Mullards, based on how they sound?

[Stevem]

I did not even listen to the clips because the stronger the given tube is the more it's going to impart its peticluar sonic character into the sound of the amp, be that good or bad in terms of what you are looking for and or expecting

[whatdisay]

I did not even listen to the clips because the stronger the given tube is the more it's going to impart its peticluar sonic character into the sound of the amp, be that good or bad in terms of what you are looking for and or expecting

Got it!

I appreciate you not listening. Sincerely.