Unless the load draws constant current, the output impedance of this thing is so high that variation of load current will make the output voltage vary a lot more than whatever noise it could have filtered...
That's exactly the point: you can't possibly say whether it's a good or a bad design if you don't know what it is meant for. Apparently it is for some sort of headphone amplifier; if it is an exotic kind of headphone amplifier with constant supply current, poor PSRR and very high SNR target, then this may be a sensible solution. On the other hand, if it's an amplifier with signal-dependent supply current and very poor PSRR, then this supply could dominate the distortion. If it's a headphone amplifier with very good PSRR, then it doesn't matter at all.
Not trying to use it for anything exotic.
I need a good bipolar 12VDC supply for simple op-amp circuits similar to the CMOY.
I need a good bipolar 12VDC supply for simple op-amp circuits similar to the CMOY.
Then I agree with peufeu. Op-amp circuits usually have good PSRR, at least at low frequencies, and their class-AB output stages draw distorted currents from their supplies. Hence, the capacitance multiplier will probably have no measurable effect on the circuit's performance, but if it does, it will probably just increase distortion.
So the circuit is okay for op-amp circuits or not?
If not, how about posting a 12VDC bipolar supply schematic that is optimal for op-amp circuits?
If not, how about posting a 12VDC bipolar supply schematic that is optimal for op-amp circuits?
It is unnecessarily complicated for simple op-amp circuits. Proposed changes:
-Cut off everything to the right of C3 and C9
-Change R2 and R7 to 2 kohm (11.67 V) or 2.2 kohm (12.71 V)
-Cut off everything to the right of C3 and C9
-Change R2 and R7 to 2 kohm (11.67 V) or 2.2 kohm (12.71 V)
Just use the LM317/337 and dispense with the window dressing of "capacitance multiplier". All that stuff in this case is of no practical use.
the typical cheaper 3pin regulators have quite poor high frequency performance.
They will give a better output if you don't feed lots of high frequency interference into them.
The better location for enhanced interference suppression is BEFORE the 3pin regulator.
You can start this by using an IEC socket with the steel canned interference filter integrated inside.
Then you use a transformer that has close coupled input and output wiring.
Then you use effective filtering after the rectifier.
Some may want to add in a secondary winding snubber to avoid the potential for ringing of the supply when presented with step changes in current demand.
All of this is before the 3pin regulator.
place the 3pin regulator as close to the load as possible.
Run the wiring to that regulator as a clsoe coupled pair to minimise emi from the cable.
They will give a better output if you don't feed lots of high frequency interference into them.
The better location for enhanced interference suppression is BEFORE the 3pin regulator.
You can start this by using an IEC socket with the steel canned interference filter integrated inside.
Then you use a transformer that has close coupled input and output wiring.
Then you use effective filtering after the rectifier.
Some may want to add in a secondary winding snubber to avoid the potential for ringing of the supply when presented with step changes in current demand.
All of this is before the 3pin regulator.
place the 3pin regulator as close to the load as possible.
Run the wiring to that regulator as a clsoe coupled pair to minimise emi from the cable.
Alright, I'll eliminate the cap multiplier and just go with the LM regs..
Thank you for the replies.
Thank you for the replies.
http://www.audio-perfection.com/forum/showthread.php?tid=263
.
See and read here. But in Russian.
Very interesting about LM337, LM317 .
Try to use Google translater.
.
.
See and read here. But in Russian.
Very interesting about LM337, LM317 .
Try to use Google translater.
.
I was able to translate it with Google.
Without being to enlarge the images, or follow and understand all the Russian jargon, it's difficult for me to understand the whole thread.
Without being to enlarge the images, or follow and understand all the Russian jargon, it's difficult for me to understand the whole thread.
- Status
- Not open for further replies.