Jeff Morris's Taste Tests for 6V6 and 12AX7

Posted to alt.guitar.amps on Fri, 23 Jul 1999.

Here are the results of a very unscientific taste test I ran with a good friend recently. Your mileage may vary, but here's what we found out using our very flawed techniques.

The Equipment:

We used my Magnatone Varsity Deluxe 108 since it's a single ended one 6V6GT and one 12AX7 amp I thought it would truly show the differences that the tubes present. There's no reverb or tremelo in the circuit to get in the way, just pure sound. The amp is rectified by a 5Y3GT and the speaker is the stock 8" Oxford AlNico magnet speaker. The test guitar was a stock early 70's Tele, and we used a 10 foot Spectraflex cord and plugged into the amp's high impedence jack.

In an effort to make the test as "blind" as possible, I played the guitar and swapped out tubes while my good friend (the one without tinitus) took notes. I witheld my opinions while the test was in progress. Then we changed places and he played/swapped tubes while I took notes. The one taking notes never knew which tubes were being used. When we finished we compared notes and our opinions were remarkably similar. Here are the results.

The 6V6's...

  1. Visseaux 50's Metal Base
  2. Sylvania 1943 JAN
  3. RCA Black Plates
  4. Marconi
  5. Tung Sol
  6. GE
The Visseaux 50's Metal Base 6V6GT was clearly the winner. It wasn't quite as hot as the RCA (black plate), but it was MUCH more musical with substantially more clarity and sweetness. The bridge pickup produced sizzling highs that "swirled around the room". The rhythm pickup produced bluesy grind with rich, multidimensional sound. Chords were full and clear, each string was articulate.

The Sylvania 1943 JAN was the surprise runner-up with the same critique, just a little less "raunch" than the Visseaux. Seriously, these Sylvania's were fantastic and we were very surprised when we realized we had both ranked them higher than the RCA.

The RCA Black Plates come next, raunchy and hot with sizzling upper mids and highs but a little muddy compared to the Visseaux and Sylvania's. These are widely considered the Holy Grail, and they really are a fantastic sounding tube. They are clearly the choice for guitarists looking for an over the top overdrive, they compress faster and breakup more than any other tube in the test, but are less articulate than the Visseaux and Sylvania.

The Marconi JAN (Italian made) was a good middle-ground tube. Not as hot as the RCA, and not quite as musical and sweet as the others. It seemed to have elements of each in that it was a little more musical than the RCA, but not as hot.

The Tung Sol (50's vintage) and GE's (60's vintage) were good sounding tubes but inferior in every category to the tubes above.

The 12AX7's...

  1. Telefunken (ribbed plate)
  2. Amperex (50's Script Logo)
  3. Amperex Bugle Boy
  4. Mullard (old logo)
  5. RCA Black Plate (1950's stock)
  6. Tung Sol (50's stock)
  7. Mazda (Shiny Plate 50's French Military)
Here's how it broke down...

The Telefunken won in a tight race with the Amperex (Script Logo). The test really came down to finding the balance between drive and sweetness/complexity. The Amperex (script logo) was a great sounding tube and hotter than the rest. It also had excellent balance with a little added midrange bite that made me smile as I ran through some raunchy double-stops. The Telefunken had slightly less drive and lacked the accentuated midrange of the Amperex, but overall was a more musical sounding tube. It's bottom was fuller with no flabiness, and the highs were brilliant and shimmery. I could immediately see why the high-end audio nuts sell their own children for these, they really project a multi-dimensional sound that adds life to your amp.

Next were the Amperex Bugle Boys. They were very reminiscent of the Script Logo '50s Amperex tube, but lacked the "life" of the earlier tube. A fantastic tube, but didn't have that extra something found in the Tele and Script Logo Amperex.

The same may be said for the Mullard, though it presented an even greater accentuation of the mids. Great for crunchy rhythm and raunchy double-stops.

The RCA (Black plate) and Tung Sol tubes had less drive than either of those mentioned above, and both had terrific bottom and highs, though not as over the top as the earlier tubes. These are a "more polite" sound, probably a better choice for jazz or clean rhythm.

The Mazda was a little dissapointing given the hype that they've received lately by some. They came in the middle between the drive of the Mullard and the sweetness of the RCA's. A good tube, but didn't quite live up to it's pre-fight press.

Thanks to Jeff Morris for doing the testing and sharing the results with us in alt.guitar.amps .

Last updated: 10 August 1999
Taste Test copyrighted 1999 by Jeff Morris. Incidentals copyright 1999 Miles O'Neal, Austin, TX. All rights reserved.
Miles O'Neal <> [remove the "XYZZY." to make things work!] c/o RNN / 1705 Oak Forest Dr / Round Rock, TX / 78681-1514