Based on Hugh Dean's AKSA 55

[chermann]

@chermann doesnt R10 / C2 make a high pass filter? With the given values it will be 0.6Hz. increasing the capacitor with 220uF will bring it lower then 0.3Hz.

Or am I on the wrong path?

As Wd -whitedragon give me some info´s at my JAT EZ amp (21 volt rails because of darlington and some margin for 4R current peaks) :

Since the cap in theory provides constant voltage. Like any current source, you wont have constant current without a constant voltage. capacitor should be large enough since it causes a phase shift at low frequency. Distortion at low frequency could increase if not large enough. Depends on resistor values.
1.2k and 100uf is about 1 Hz filter or likely where phase shift happens so no big deal. It could actually be 47u even 22u. I tend to keep it large. If the cap used for higher voltages. I guess it more about board space if you dont want a huge cap. Such low voltages like this a 100u wont be that big.
We can just do AC analysis in sim to see if there is a phase shift to high. 100uf will be more than large enough, specially at higher voltages when you resistors can be 2 to 3k or higher

so 100µF should be enough

kr
chris

 

[MrHifiTunes]

Thanks Peter, the one from diamondstar is the one I saw before. I will look into that one. My DMM doesnt seem to work. Plugging in a BC550C and it reads 0. (The diode tester gives good values). also with my cheap Chinese tester I get some acceptable values.

Maybe beefing up the pozer supply from 15v to 30v (wich adjusted resistor values) will give some good indication for the power transistors. I will give it a try.

 

[MrHifiTunes]

As Wd -whitedragon give me some info´s at my JAT EZ amp (21 volt rails because of darlington and some margin for 4R current peaks) :

Since the cap in theory provides constant voltage. Like any current source, you wont have constant current without a constant voltage. capacitor should be large enough since it causes a phase shift at low frequency. Distortion at low frequency could increase if not large enough. Depends on resistor values.
1.2k and 100uf is about 1 Hz filter or likely where phase shift happens so no big deal. It could actually be 47u even 22u. I tend to keep it large. If the cap used for higher voltages. I guess it more about board space if you dont want a huge cap. Such low voltages like this a 100u wont be that big.
We can just do AC analysis in sim to see if there is a phase shift to high. 100uf will be more than large enough, specially at higher voltages when you resistors can be 2 to 3k or higher

so 100µF should be enough

kr
chris

Thanks for the research. Im learning a lot here. Hope I put it all in my head. Guess I have to release some rubbish out of my brain first 🙂)