DIY Power supply for a Szekeres headphone amp

[G]

Hi Bricolo,

Below is an alternate version of a Szekeras amp. It uses a CCS for biasing instead of a resistor and in theory should sound good.

G

[G]

Here is an image of a PCB that I made for the above amp.

G

[G]

Here is an image of the regulated supply PCB. I don't have the diagram for this one yet. I took the Welborne Labs PS1 diagram and just used the positive half. It's basically a Jung regulator. They are made using ExpressPCB and each is layed out on a "miniboard". You can get three of each board for $120 USD. Less if there are others that want a set of boards and you do a group purchase. The way things look with my hobby funding I may never get to use the boards or the design so I figure that somebody should. Just email me if you want the files and I will send them to you. Oh,by the way The Szekeras is really meant to drive lo impedance loads. If you want to use Sennheiser HD580's a good Cmoy or Meta is all that you will need.

G

[Bricolo]

Thanks all!

Your advices and links helped me a lot.

After having read more than 50 web pages (!!!) I think i'll go for the classical szekeres amp (the one i've put on my first post)

Maybe I'll go later for the CCS one.
More linear amps like the DOZ will be too dificult to build for a first diy project.

I'll maybe build a Zen, with speakers, later.



For the PS, i'll also use the picture i've posted, with those values:

100nF for the primary
1*4700µF instead of each 2*15000µF
2.2mH for the self (I've kept the original value, i think it isn't optimal, but I've found no infos about values for a Pi filter)
4.7µF for the last condenser

and maybe a 100nF capa in parallel with each gate's diode




Wants someone add something?

[G]

Just make sure to use good low impedance capacitors in the power supply and on the output and have fun. Let us know how it turns out.

G

[halojoy]

A bipolar buffer amp for Headphones.

With BC550C driving a MJE15030(PNP)
in FOLDBACK.
Say we let BC550 have some 5-10 mA currents.
And the MJE15030 having 100 mA. Would be enough for most.

And same as a constant current source.
Use an BC550, amplified diode mode, as referens

Polypropylen for input.
Say 10-20 kOhm input impedance.
Not fond of 47-100 kohm.
Most sources wouldn't suffer from 10 kohm.

And then a pair of OSCON caps, in parallell, for output.

For supply I'd use DC-source. One or two 12 V Car-batteries
See this thread:
Battery or Accu Power supply

Couldn't be bad.
Could turn out to be real good.
--------------------------------------------------------------
No exotic components. With the magic letters "FET".
People like to beleive in magic. Gold fever!
But "exotic" is not the same as superior or good.
If gold was to find everywhere around your house
it wouldn't be expensive, or desirable/expensive.
But it would still be gold!

Bipolar is to be found anywhere.
They have lost the exotic label, they had when they first arrived.
But they still are better choice for some applications
than anything with FET in its name.

Different devices have their strenghts and shortcomings.
Used in their right place, they do the job best.
In the wrong application, they do not do an optimal job.

[trwh]

Bricolo,

"More linear amps like the DOZ will be too dificult to build for a first diy project."

Rod sells boards for the DOZ headphone amp if you are concerned about difficulty, I would give it some further consideration. The distortion figures of the Szkeres amp are likely to be quite poor - it is easy to improve on them. Also, bear in mind a classic "cmoy" op-amp based headphone amplifier is more foolproof and cheaper to build than the Szkeres.

Whatever you build, have fun with your first DIY project!
Tim.

[traderbam]

Bricolo,
I like your simple design. It will sound better if you can use a split rail supply (can you?). This will allow you to eliminate R1,R2,R3. You can ditch the diodes. The input cap should go upstream of the potentiometer. This is simpler and will reduce psu noise and distortion from being added to the input signal via the bias resistors. If you cannot use a split rail supply then make sure your psu is very good.
BAM

PS: Where does this name "Szekeres" come from? This is just a simple source follower - been used since the beginning of time.

[halojoy]

It comes from this member. See link below.
Years ago he published his own project.
since then many have liked it. So many that his construction is famous.

Similar story have Nelson Pass.
Before his amplifiers he was unknown.

Next in line could be "traderbam":
- Have you heard my new version of traderbam Amp.
- Yes. Now I will build my own.

http://www.diyaudio.com/forums/membe...fo&userid=2734

[G]

Here is the direct coupled version Trader. If you know that your source has a output cap you can eleiminate C1. (obviously)

G