Hi Mark,
Tonight I fired up the 12B4 preamp, and I must say, I like what I hear!
The preamp was hastily assembled on my preamp prototyping "board" and it uses "silly" parts that I have in my bin
The input capacitor is Illinois Cap, the output capacitor is Auricap, the plate resistor is Japanese-made Kiwame and the rest of the resistors are carbon composition. The power supply caps are Rubycon.
It is not yet optimized, as the B+ is only 200V. With that voltage I was able to measure 6.9V on the cathode which yields around 17mA per tube. However, I can live with the sound. I can't compare it with my Foreplay (hasn't been returned yet), but I will compare it with my other preamp that uses Western Electric 407A.
I've attached the schematic of how it currently is, and some pictures for you.
Go for it!
Tonight I fired up the 12B4 preamp, and I must say, I like what I hear!
The preamp was hastily assembled on my preamp prototyping "board" and it uses "silly" parts that I have in my bin
The input capacitor is Illinois Cap, the output capacitor is Auricap, the plate resistor is Japanese-made Kiwame and the rest of the resistors are carbon composition. The power supply caps are Rubycon.
It is not yet optimized, as the B+ is only 200V. With that voltage I was able to measure 6.9V on the cathode which yields around 17mA per tube. However, I can live with the sound. I can't compare it with my Foreplay (hasn't been returned yet), but I will compare it with my other preamp that uses Western Electric 407A.
I've attached the schematic of how it currently is, and some pictures for you.
Go for it!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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