TragicTravisty wrote:so could you just replace the 6l6 in say a champ with a 12ax7? and everything would work out?
Hmm, no, it's not that simple.
In the Killer Ant, as said in the sewatt.com thread, the OT has 50 kOhm primary impedance (10 times the usual impedance for a EL84), because a preamp tube can not pass as much current as a power tube. It also has a different cathode resistor, and in this case no cathode decoupling cap.
Not quite a direct replacement !
gwtekman, from sewatt.com forum, wrote:Interesting little amp. PT has 250v secondary. OT is 50K ohm primary.
Looks like a scratch build could use a reverb driver transformer (typically around 25000 / 8 ) using a 16 ohm speaker?
Few other notes :
Wall voltage = 119V
Output at Power transformer 244V
+B to Output Transformer = 313V
V2B Plate = 307V
V2A P;ate = 274V
V1B Plate = 172V
V1A Plate = 170V
For other designs using low gain (but higher current) preamp tubes as power tubes you can look at the FireFly, and the 6n1p output tube option for the P1, both at AX84.com. There is also the Gilmore Jr. but i did not find a schematic for it.
I tried once a 6n1p (only one triode connected) in place of an EL84, it was humming a lot but the power was effectivey reduced by a fair amount. Maybe i should try again, with both triodes in parallel.