The DAO SE all-FET Class-A ZGF Headphone Amplifier

A few more images:

'Da Bomb', the capacitor bank with integrated cap multipliers (four of them!)

Heat spreaders top and bottom connected with aluminum rods to transfer the heat to the bottom plate of the case.
 

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The cap multipliers are 317_337 based as used in the F5-HA.

The Didden Regulators are not the standard version but a XEN modified version.
Jan was given the first ever pair a couple of years ago to measure / treasure. :)
The pin out as shown by Oliver is 78xx / 79xx compatible, with two addition optional sense pins.
Overall size is ~ 13x35mm, with a TO220 power device which can be mounted to a heat sink at the back.
You can see the mounting hole clearly on the PCB.


It uses degenerated 2SK209s for the two CCS, and a JFET input opamp such as OPA1641.
The LM329s are replaced by 3x SMD red LED in series.
And the power supply to the opamp is decoupled at HF from the regulator output.
This, IMHO, enhances stability greatly, so that it has no issue with low ESR output caps.
The audio caps I tried such as Nichicon KA or Elna Silmic II are all fine.


Patrick
 

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Stixx's proto is singing.

Noise issue with the HAGS now completely solved.
Background totally dark.
HAGS bandwidth is 700kHz -3dB, nice first order drop.
DAO TCS has 400kHz bandwidth at -1dB.
(My func gen cannot go much higher without large overshoot)

So everything works as planned. ;)


Patrick

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Probably the most 'sophisticated' regulator circuit I tried with the DAO amp and the AKGs was a 'beefer-up' Salas shunt reg (about 350mA) but reverted back to a well organised traditional C-R-C supply with the 'R' replaced by 'simple' C-Multiplier - to me, the regulators seemed to have maybe better transients and such but lacked a lot of 'air' and 'life' (PRAT I think they call it, sorry for the vague terms) - haven't changed it since which is most unusual for me!

I think a couple of guys tried those Jan Didden super-regulators and the older minimum feedback Pooge style ones but unsure of results - perhaps you might have more success with some of the newer types of fast, low noise chip regulators...
 
Our version is only available as part of the project.
But you can buy larger ones from the DIYA store.


Thank you for your interest,
Patrick

thank you Patrick
I will look at larger ones but feel that I need the ones posted here and they can become bestsellers

Probably the most 'sophisticated' regulator circuit I tried with the DAO amp and the AKGs was a 'beefer-up' Salas shunt reg (about 350mA) but reverted back to a well organised traditional C-R-C supply with the 'R' replaced by 'simple' C-Multiplier - to me, the regulators seemed to have maybe better transients and such but lacked a lot of 'air' and 'life' (PRAT I think they call it, sorry for the vague terms) - haven't changed it since which is most unusual for me!

I think a couple of guys tried those Jan Didden super-regulators and the older minimum feedback Pooge style ones but unsure of results - perhaps you might have more success with some of the newer types of fast, low noise chip regulators...

thank you for advice
I like Salas BiB but It Is very big
 
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