Bare Knuckle Pickups Forum
Forum Ringside => Guitars, Amps and Effects => Topic started by: hermetico on April 02, 2010, 02:14:11 AM
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Hi there,
Today, I did the tube swapping dance in the pre-amp section of my Night Train.
As you know, stock, the amp sounds great but the sound becomes undefined if the gain is past 3/4 and the volume also is so, I decided to check alternative 12AX7 tubes for V1 and V2, all current production ones.
Maybe this info can help someone, maybe not. Tone is a matter of taste.
Checked valves were:
Sovtek 12AX7-WA (stock)
Tesla/JJ ECC83-S
Electro-Harmonix 12AX7
Tung Sol 12AX7
TAD 7025-S (mullard-like)
My impressions:
Sovtek 12AX7-WA do its job. Only sounding confussing when going under very high gain. It works just good if you haven't anything to compare with.
Tesla/JJ ECC83-S. Mounted a pair in V1 and V2. There is a clear jump one step above respect of the stock ones. The sound is cristal clear, very detailed and defined. The tube has a very late break up so, it's special interesting when a lot of clean headroom is wanted. I found this valve as sounding excesivelly trebly in my amp so, I removed the pair and checked the rest.
EH 12AX7. If it was a jump to go from the Sovtek to the JJ, same jump was going for that EH. The EH is probably the best ballanced valve of those tested. Cristaline clear, very defined and detailed, warm and with a very smooth high ends, very silky. Breaks up earlier than the JJ (and in a very good way, always smooth and controlled) but late than the rest. I liked a lot this valve and, as I found it very balanced, I let one in V2 and followed swapping V1 with the rest.
Tung Sol. This one plays in the same league as the EH. Same quality of sound but, the EQ is slightly boosted in basses and more clearly in trebles (but still not so trebly as the JJ). The sound is live, detailed and defined. Breaks up earlier than the EH but later than the TAD. Very powerful under high gain, never going muddy. A little bit in the treble side, tested with an strato.
TAD 7025-S. I didn't expected anything good from this one, since TAD sometimes designes their own interpretation of some valves that can be love or hate it. But, this tube was in the same league of the other two. Very detailed, defined and musical. Slightly darker than the EH and with the earlier break up of the three. When it breaks, has the more special tone. There is some kind of little dust motes in the sound structure that remembers me to that random rawness that is in a cranked JCM800 or JTM-45 (you know, sound is really difficult to define but, I hope you get me).
I checked those, leaving the stock Sovtek EL84 power-amp tubes (that I know are good, maybe not the best but, really good).
I checked first with volume at noon and gain at 1/4, then, I increased the gain to 2/4, 3/4 and 4/4 for each round.
Then, I finally cranked everything up, gain at 4/4 and volume also.
I checked first in clean and then with OD and with OD + Mesa-type disto.
Gear used:
Guitar:
Fender American Deluxe HSS Stratocaster. Modded to SSS, with my particular Hermetico's Stratosphear #4 mod and loaded with a set of callibrated BKP's Mother's Milk pickups.
Amp:
Vox Night Train with matched Vox 1x12 cab (G12H speaker, stock).
Pedalboard:
MXR CAE MC-401 (booster / Line Driver)
Vox 847 re-issue Wah
Voodoo Labs Vibe
AMT California
Fulltone OCD V3
Korg Pitchblade+
Line6 Verbzilla
For each round I did:
Clean guitar, no effects
MXR MC-401, +12dB to put the valves in their sweet spot
MXR and OCD (crunch tones)
MXR, OCD and AMT California (Mesa-like distortion)
My conclussions:
There is clear gap between the Sovtek and the JJ but, the same gap is between the JJ and the other three.
The JJ could work really nice in darker amps and when a the need to keep the amp clean is a must, since are the harder to break up.
In my opinion, you (at least me) cannot go wrong with any of those three. It's more a matter of taste that anything else.
From those three, I will stock the EH for sure. It matches the description I read in several reviews. It's a very well balanced tube. Works fine in any position, sounds nice, silky and very round and, will solve any microphonic issue when others couldn't. I let one in V2 but, I could perfectly let both there.
The Tung Sol is a little bit trebly for this amp, to my taste but, taking into account that the test was performed with a bright guitar, maybe it could be the best election after testing the amp with an LP-clone, darker wood and pickups. Will see.
The TAD is the one having the earlier break up and works specially nice for dirty sound. Has the more special character, IMHO, and works better for blues and hard rock (something that matches my needs).
So, after testing the amp with an stratocaster, I let the TAD in V1 and the EH in V2 but, this can change when testing the amp with my LP-clone.
More to come in a few weeks.