Ah, heck, just take 'em down to the corner drugstore and use their tube tester for free... Oh, wait, it's 2011.
I remember going with my dad in 1968-69 to check a tube on our old Packard-Bell b&w television... got it replaced just in time to watch my favorite show, "Mutual of Omaha's Wild Kingdom." (That Marlin Perkins was pretty tough for an old guy.)
Never occured to me that I'd one day be using those vacuum tube thingies to amplify guitars.
You can almost feel the current flowing
You can almost see the circuits blowing
Round #1 of preamp tube testing yielded the following current tube arrangement:
V1 - Brimar CV4004
V2 - Mullard 12AX7
V4/PI - Mullard CV4024 (quite a HUGE change going from any of the 12AX7 to this)
V3 - JJ ECC83S
The Mullard and Bugle Boy were very similar...not really a discernible difference in V1.
The Brimar was a bit darker sounding than the Mullard and BB in V1...not really better or worse...but certainly improved with the Mullard replacement of JJ in V2.
The Telefunken.....well it never found a home on this go 'round. It didn't seem to be as "crisp"...if that describes it right. Maybe on the next round our ears will tell us something different.
I should note that the previous arrrangement was all JJ ECC83S straight across the board so the amp had some snarling teeth with lots of punch....not particularly bad sounding at all...just not the tone we had in mind.
Power tubes - I know maybe a whole other story...but the amp came with Svetlana EL34's made in Russia. They are not the =C= tubes...I think just regular new production Svets. They sound good. I have matched pairs of JJ E34L's, Groove Tube EL3434M's, and I have some JJ KT77's. Someday I'll see if there are much differences.
We had similar results testing new JJ 12ax7's, in our new HI-TONE Amp line. While they aren't quite a Mullard or Brimar, they are good sounding tubes. As one of my old best friends used to say, "They don't suck".
.
