I am thinking of using the Bride of Zen as a combined preamplifier and voltage amplifier to drive my power buffer (with no voltage gain). Therefore, I have to place my 50k volume potentiometer before the BoZ. I am afraid the high frequency impact is too large with this potentiometer without cascoding.
So, has someone tried a cascoded version of the Boz?
So, has someone tried a cascoded version of the Boz?
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I did, and it didn't bring me much happiness either......So, has someone tried a cascoded version of the Boz?
I suggest attached circuit:
Input buffer (Q1,Q2) gets you rid of the input cap and isolates the pot so you don't have to worry about it.
Amplifying MOSFET (Q3) works with local Schade feedback in triode mode, loaded with CCS (Q4,Q5).
Zout is about 150 R .
Gain (about 20dB) is set with R7/R5 ratio and half of the PSU voltage at Q3's drain is set with R6 (depending on Q3's Vgs/Id characteristic).
This circuit has much better PSRR than original. It will deliver more than 20V_peak of clean swing at the output and is linear up to almost 100kHz.
Of course, it can be further improved in many ways - first thing would be to use 2sk2013 instad of IRF610 for Q3.
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