Hakuin SE Class A HP Amp

[MladenGavric]

Thanks X, it means a lot!

I'm a bit lost in translation on this one (english is not my first language):

I would add 1uF to 2.2uF 50v Wima MKS (or MKP if you have space) across C4.

Could you quickly scribble/doodle it on my previous attachment, please.

 

[xrk971]

Here you go.

 

[MladenGavric]

Thank you, once again!

Enjoy the rest of your day! And sorry for any inconvenience.

 

[MladenGavric]

Just a quick question: What is input voltage and current for Hakuin?

 

[MladenGavric]

24V 70mA?

 

[xrk971]

Yes that works, but might have excessive heat. 18v is fine for most headphones. If driving lower impedance headphones, increase current. But for the small on PCB heatsink, I would not go above 70mA.

 

[Dibya]

I am copying 2SA1587 model to LTSpice LIB folder but it is not working.
I got my model from Toshiba: 2SA1587 | Bipolar Transistors / IGBTs | Toshiba Electronic Devices & Storage Corporation | Asia-English
Are they providing fake LTSpice model?

 

[xrk971]

Just paste it directly into the schematic as .model directive. Then you won’t need library path to be set up correctly.

 

[Dibya]

Their is no .model file inside the archive.
Edit:
It seems model is their but their is showing
Here is Log:
Circuit: * D:\2SA1587_LTspice_20190322\Hakuin-v3.1.asc

Fatal Error: Multiple instances of "A2"
Thanks for All help.

 

[xrk971]

I just downloaded the lib file from Toshiba, renamed it with a .txt extension and opened it with a text editor. I pulled out the .Model and pasted it into my LTSpice sim of the Hakuin and it works fine. Looks like a good transistor. Please see the 2SA1587 model below.

*  (C)  Copyright 2017 Toshiba Electronic Devices & Storage Corporation
*  Date:                19/09/2017
*  Part Number:         2SA1587
*  Parameter Ver.:      Ver.1
*  Simulator:           PSpice
*  Model Call Name:     2SA1587
*  TNOM:                25 degree
*  Pin Assign:          1=Collector 2=Base 3=Emitter
 
.MODEL 2SA1587 PNP(
+ LEVEL = 1
+ TNOM = 25
+ IS = 1.2e-013
+ BF = 380
+ IKF = 3.3
+ ISE = 1
+ NE = 1.6
+ NK = 0.89
+ XTB = 1.5
+ XTI = 2.1
+ NF = 1
+ VAF = 43
+ VAR = 50
+ BR = 0.8
+ IKR = 0.7
+ ISC = 1e-011
+ NR = 1
+ NC = 1.8
+ RB = 42
+ RC = 3.2
+ CJC = 1.25E-011
+ MJC = 0.427
+ VJC = 0.75
+ CJE = 1e-11
+ MJE = 0.33
+ VJE = 0.75
+ TR = 1E-009
+ TF = 1.07E-009)
.ENDS

Just paste the above (you can leave off the comments preceded by the * if you want) into the shematic as a directive and then change the name of the BJT from 2SA1837 to 2SA1587. It should work.

That part is only $0.27 from Mouser - good for 100mA. I also like using the DZT5401 ($0.40) - good for 600mA.

https://www.mouser.com/ProductDetail/Diodes-Incorporated/DZT5401-13?qs=oDfC%2Bbpzniz//mcSN5ZbUQ==

 

[Dibya]

Thanks X,
With 2SA1587 & R2 Set to 120Ohms I got this
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 4.626e-01 1.000e+00 0.11° 0.00°
2 2.000e+03 1.092e-04 2.361e-04 -90.05° -90.15°
3 3.000e+03 1.999e-06 4.321e-06 0.33° 0.23°
4 4.000e+03 2.461e-07 5.321e-07 165.78° 165.67°
5 5.000e+03 1.923e-07 4.156e-07 -179.99° -180.09°
6 6.000e+03 1.588e-07 3.432e-07 -179.98° -180.08°
7 7.000e+03 1.361e-07 2.941e-07 -180.00° -180.10°
8 8.000e+03 1.191e-07 2.573e-07 -180.00° -180.10°
9 9.000e+03 1.058e-07 2.287e-07 -180.00° -180.10°
Total Harmonic Distortion: 0.023617%(0.023614%)
Can 120ohm harm the transistor?

 

[xrk971]

For R2=120R, Vcc=24v, I got 70mA bias current - about perfect for a 100mA max rating. It should be fine.

 

[Dibya]

@xrk971
With 18v , I got this. 2SK209GR + 2SA1587 can be a really good Altoid Can AMP. 0.04% THD on 250Ohms.
What you think?
Can We call it PHA(Pocket Haikun Amplifier)?
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 4.991e-01 1.000e+00 0.10° 0.00°
2 2.000e+03 2.367e-04 4.743e-04 -89.92° -90.02°
3 3.000e+03 7.233e-06 1.449e-05 0.30° 0.19°
4 4.000e+03 3.754e-07 7.522e-07 130.15° 130.05°
5 5.000e+03 2.038e-07 4.084e-07 -179.98° -180.08°
6 6.000e+03 1.601e-07 3.208e-07 -179.82° -179.93°
7 7.000e+03 1.372e-07 2.749e-07 180.00° 179.89°
8 8.000e+03 1.200e-07 2.405e-07 180.00° 179.89°
9 9.000e+03 1.067e-07 2.138e-07 180.00° 179.90°
Total Harmonic Distortion: 0.047455%(0.047453%)

 

[Dibya]

I lowered R2 to 100ohms and 18V supply.
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 4.075e-01 1.000e+00 0.11° 0.00°
2 2.000e+03 1.603e-04 3.933e-04 -89.94° -90.05°
3 3.000e+03 4.435e-06 1.088e-05 0.30° 0.20°
4 4.000e+03 2.605e-07 6.392e-07 140.89° 140.79°
5 5.000e+03 1.670e-07 4.097e-07 -179.98° -180.09°
6 6.000e+03 1.340e-07 3.288e-07 -179.90° -180.00°
7 7.000e+03 1.148e-07 2.818e-07 -180.00° -180.10°
8 8.000e+03 1.005e-07 2.466e-07 -180.00° -180.11°
9 9.000e+03 8.930e-08 2.191e-07 -180.00° -180.11°
Total Harmonic Distortion: 0.039341%(0.039339%)

 

[xrk971]

Looks good - you should build it! PHA is fine with me

 

[Bambinz]

There are some upgrades in the circuit?

I would like realize one of them for the AKG 240MKII.
Do you have also a DAC schematics?

 

[twocents]

The Hakuin should be an excellent choice for most headphones. I have not built my Hakuin yet, but with the PCA my AKG 240MKII's never sounded so good. Better than with my tube amps.

 

[xrk971]

There are some upgrades in the circuit?

I would like realize one of them for the AKG 240MKII.
Do you have also a DAC schematics?

No, the schematic of amp has not changed. The PSU battery level meter still needs to be fixed but otherwise works. Just had not been enough interest on this project for me to get in and debug it.

I don’t have a DAC for this design.

 

[ItsAllInMyHead]

Per usual, your timing is impeccable. I am finally (sigh) getting back to the bench after a long hiatus. I have a list of projects. One, of course, is figuring out what the heck I did to goof up the amp sections of two amps by simply changing the bias on one device to lower the dissipation from our previous troubleshooting/optimization. It's clearly assembly error on my part, but I never had the chance to get it done. With a bit of new skills, I may be able to get it back to normal on the amp side.

Then the fun begins to try out the alignment and bodge in the parts that JPS was so kind to lay out and see if I can get all the LEDs to function as intended for the power meter using the new voltage reference.

It may take me some time through the winter, but this project is definitely not sitting on the bench forgotten.

 

[Bambinz]

Thank you very much for the answers!
Twocents what is the PCA?

xrk971, can I use your schematic as a base for my owm design?
I would like to try to implement also a DAC directly on the PCB