RnFR wrote:feel free to post schematic/demo/anything!
Hi RnFR,
Recently I build a clone of an Orange Micro Terror (
viewtopic.php?f=2&t=22030&p=267139&hilit=micro+terror#p267139 ) but instead a 12AX7 successfully adapt for the preamp section an oddball (and CHEAP !) tube.
The ECF801 is a dual section tube used mainly in black and white TV tuners. Here is their datasheet:
https://frank.pocnet.net/sheets/010/p/PCF801.pdf If you look at the diagram of the Micro Terror you find that the cathodes of both triode sections of a 12AX7 are connected directly to ground. The resistors and condensers surround this tube are of the same values than those indicated in that diagram.
This TV tuner tube ALREADY have connected internally its two cathodes, but one section is a triode and the other a pentode. (If you tie together the pins 6 and 7 acting as a anode you have a pair of triodes in the same bottle). This tube is normally disregarded due the fact that both sections can't be used separately.
Look further: the Butler tube driver also can be built using this tube instead to a 12AX7 since both cathodes are connected at the same circuit point in these pedals. This tube is 6mm shorter in height than 12A..7 family and have a better response in starved anode operation. IMHO
The heater runs at 8.5 V and draw 300 mA so you need an adequate power resistor in series to adapt to the supply that usually will be from 9 to 15 Vdc in pedals using tubes at low voltages.
In few days I promise to post some pictures in another thread to not derail this subject referred to Korg Nutube
Cheers,
Jose