I just dreamt up this amplifier, based on the Sony/Apex topology with the fully symmetrical IPS, but with a triple deep darlington output stage similar to that of the Leach Low TIM amp.
It simulates 0.00381% THD at 20kHz at a RMS power of 200+ watts into 4 ohms, with a phase shift of only 0.64 degrees.
The DC offset with the values shown is about 32mV which is acceptable, bias is about 60-70mA per output pair.
The first draft schematic:
It simulates 0.00381% THD at 20kHz at a RMS power of 200+ watts into 4 ohms, with a phase shift of only 0.64 degrees.
The DC offset with the values shown is about 32mV which is acceptable, bias is about 60-70mA per output pair.
The first draft schematic:
Attachments
The 200W was based on the only transformer i have that gives me 60V rails.
However i realized minutes after posting this that VAS was dissipating almost 5 watts and the IPS around half a watt.
After correcting this and getting the offset back down to 30mV or less, THD had risen to 0.4%
so it needs some extreme work.
However i realized minutes after posting this that VAS was dissipating almost 5 watts and the IPS around half a watt.
After correcting this and getting the offset back down to 30mV or less, THD had risen to 0.4%
so it needs some extreme work.
Along the lines of an old KRELL KSA50 but with CCS in the input. Once optimised it should sound good. Complimentary symmetrical amps sound somewhat clinical but I like that kind of cold characterless sound.
Just on brief inspection, I would increase R9, R11. Reduce the input pair's current somewhat and increase R10, R12. Decrease values of C1, C2 and maybe add a cap across R18 to extend phase margin.
Just on brief inspection, I would increase R9, R11. Reduce the input pair's current somewhat and increase R10, R12. Decrease values of C1, C2 and maybe add a cap across R18 to extend phase margin.
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