DIY Power supply for a Szekeres headphone amp

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Tomo

Tomo

Member
Joined 2002
Hello,

Here is one PSU you might be looking for.

An externally hosted image should be here but it was not working when we last tested it.


But then you should be very careful with 40,000uF.

Enjoy!

Traderbam -

"In any case, this design does not require matching as it is single-ended."

Cool. I did not know that. This would make my life easy indeed.

And like you have said, I think DC coupled operation isn't so ... nice. Offset is annoying to play with for lazy bum like myself. I got fed up and never tried again. But I think you will be happy with coupling caps.

Don't worry, I will try some BJT when I get a chance. I never said they are bad. I found it difficult to play with ... back when I was building this amp. ... darn 3~4 years ago! Now I do play with BJT.

Tomo
 
Tomo

Tomo

Member
Joined 2002
Hello,

RJM has used this design in his Szkeres-JFet alternative. So it works. I guess if you know how to do it right, you can have as much capacitance as you want.

Vripple2 = Vripple1*1.77/(L * C)

L is in Henry.
C is in micro-farad.

So in your case.

Vripple2/Vripple1=0.085

with L = 2.2mH, C = 4700uF X 2.

That I think is a good value.

Tomo
 
UrSv

UrSv

Member
Joined 2002
Bricolo/Tomo,

Kristjan replied that the power supply is not regulated because it isn't. It is "smoothed" or "filtered" but not regulated. It is the unregulated kind. What is recommended for this amp is a regulated supply if I have quickly read the thread and the first schematic right. That means an ACTIVE regulator supply. This could be anything from an LM317/LT1086 or other linear regulator chip to some discrete regulator of some kind.

/UrSv
 
Bricolo

Bricolo

Member
Joined 2002
OK, now I'm sure it's the 2SK216
thanks



but now, since it has other specs that the IRF510, I need to re-calculate every resistor value

How can I do this? Can you give me some formulas?
fa-schmidt hasn't said the values he used :/ he only said the bias current he used fot the 2sk216 was 250mA

what is the bias current?
 
UrSv

UrSv

Member
Joined 2002
No. For a FET there is no current flowing in through the Gate as such. I(D) = I(S) in the cases where no other currents are present. In case of an amp there will be some current going to the load so in this case it is not true. In this case it is 250 mA when the amp is not used i.e. the DC bias current.

/UrSv
 
G

G

Member
Joined 2002
The ouptut will be in class A no matter where your bias point is. There is only one device in the circuit. The voltage at the gate is biased a 2/3 of the VDD. In other words 10 volts. There is no current flow through the gate to source( or there is so small an amount that it is insignificant). Use Rs to adjust the current flow through the FET.

G
 
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