EWBrown wrote:Just plug the 5751 ansd 12BH7(a) in and run with it, plug 'n' play, no modifications needed. Another nice 12AX7 alternative is the 7025, though these usually don't come for cheap :o
With a little etch "surgery" to allow using pins 4 and 5 separately for the 6.3 VAC filament power, 6CG7/6FQ7 or 6GU7 could be used for the phase splitter.
6CG7/6FQ7 is identical in character to a 6SN7, and 6GU7 is basically a 6V 12BH7A.
Now, my question is, is there an 8V filament equivalent or close equivalent to a 12AX7 or 5751?
If there is, then one can go the "plinker" route, and use 8CG7/8FQ7, or 8GU7, and four 8BQ5s. and save a lot on the NOS tube costs. Of course, the 12AX7/5751 could simply use a couple of 2.7 ohm, 1W resistors to drop the filament voltege from 8V to 6.3V, with a little bit more etch surgery Yellow_Light_Colorz_PDT_20
And of course, an 8V, 3A AC or DC power source would be needed to do this .
/ed B in NH
You could also use a 6AX7, 7AU7, 9AU7