I have build VSSA and then inspire by Lazy Cat who achieve 0,0001% THD at 1kHz, 1W/8Ohm with his First One, I want to modify my VSSA.
Please help me to optimize this design for lower THD and to make stable. I want to make this design as simple as possible. Any suggestion are welcome.
Anistardi
Please help me to optimize this design for lower THD and to make stable. I want to make this design as simple as possible. Any suggestion are welcome.
Anistardi
It's a CFA , needs regulation /CCS's .. no way around it.
It's 2 big caps make THD .01% at 20hz. No way around that without
a servo. HF is extraordinary, PPM all the way to 100k.
Below is what I settled on for this design. It will be my second CFA
IPS. (with servo)
PS - make stable ???? It will run with NO compensation ...
Also , heck with the "THD fetish" , I want PSRR , no drift/DC , run cool and to last for 20 years.
.001% and below is a good target.
OS
It's 2 big caps make THD .01% at 20hz. No way around that without
a servo. HF is extraordinary, PPM all the way to 100k.
Below is what I settled on for this design. It will be my second CFA
IPS. (with servo)
PS - make stable ???? It will run with NO compensation ...
Also , heck with the "THD fetish" , I want PSRR , no drift/DC , run cool and to last for 20 years.
.001% and below is a good target.
OS
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It's a CFA , needs regulation /CCS's .. no way around it.
It's 2 big caps make THD .01% at 20hz. No way around that without
a servo. HF is extraordinary, PPM all the way to 100k.
Below is what I settled on for this design. It will be my second CFA
IPS. (with servo)
PS - make stable ???? It will run with NO compensation ...
Also , heck with the "THD fetish" , I want PSRR , no drift/DC , run cool and to last for 20 years.
.001% and below is a good target.
OS
I want to trade THD 20 Hz for simplicities. Btw, my ears more sensitive at high freq
. May be I add capacitance multiplier for IPS.
I want to trade THD 20 Hz for simplicities. Btw, my ears more sensitive at high freq
Yes , C mult. is "big one" ... CCS is also a real game changer.
Actually , the VSSA is the best of my simulated CFA's for LF WITH caps.
(.006% 20hz -2200u caps) ....
OS
Almost finish. Very low THD
With optimize bias current of output transistors, it give:
121W/8Ohm, 1kHz, 0.000076%
121W/8Ohm, 20kHz, 0.000559%
If implemented correctly, I'm sure it will comparable to LC's First One
.I was finished to draw OPS PCB like OS's style. But I must make some software for my friend now.
It might be a little more complicated , but drop my new servo in.
"Cleaner" (filter) .. none of my 300 sevice manuals's servo examples even
came close.
OS
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It might be a little more complicated , but drop my new servo in.
"Cleaner" (filter) .. none of my 300 sevice manuals's servo examples even
came close.
OS
Low pass filter before integrator? Thank you, OS.
If the -3dB cutoff is still 5Hz.... that is too high IME. Especially for users with LP systems... W & F and rumble etc has a lot of low freq noise.
Thx-RNMarsh
If the -3dB cutoff is still 5Hz.... that is too high IME. Especially for users with LP systems... W & F and rumble etc has a lot of low freq noise.
Thx-RNMarsh
How about this? The -3db is 2Hz. Is it enough? Btw, I do not have LP. I use digital player.
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