ZEN-like headphones amp

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r_jik45

Member
Joined 2005
K

knauf1919

Member
Joined 2015
That's all. I hope there was no mistake.
Good luck!!!!

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:cop:
Please see post #269 which contains updated and corrected files.
 

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  • MINI-ZEN silk layer.pdf
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  • MINI-ZEN top layer.pdf
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tortello

tortello

Member
Joined 2001
r_jik45 said:
Here are the ones I checked/subscribed to:

ZEN-like headphones amp, this one, started by tortello
New MINI ZEN Headphone Amp PCB group order..., started by digi01
My new ZEN-like headphones amp, started by Algar_emi
MINI ZEN pcb show, about the pcb, started by digi01
One more mini Zen... almost!, that I started regarding the troubles with this amp :)
There might be others ;)
Click to expand...

The first is the original one, and was the project also pubblished in Headwize. Not sure if this site is still alive...
AFAIK more than 300 amplifier have been built according the original project, or at list 300+ are the guys who contacted me about.
Have fun to all diyers,

Marcello (Tortello)
 
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r_jik45

Member
Joined 2005
Marcello,
Thanks for posting again in here about your work :)
Headwize is no more, but the project can still be found with web.archive.org: The Zen Headphone Amplifier | HeadWize.
Likely a lot of people were, and are still, interested in this headphone amplifier. As far as I read/understood, the filtering of the power supply sounds critical.

knauf1919,
Thanks for posting your files :)
So far an independant power supply seems to be the way to go :scratch2:
 
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R

r_jik45

Member
Joined 2005
knauf1919,
Do you know The Saint TV serie?
The symbols on your pcb reminds me about it.

250px-The_Saint_titlecard.jpg
 
R

r_jik45

Member
Joined 2005
knauf1919 said:
Hello again,
I allocated half an hour to the project. The power supply was made from an assembly with LM338 and 10000uF.
For the first time I forgot to connect GND IN to earth. So does the transformer housing.
Now everything is fine and there are no suspicious noises. I didn't have time to see the oscilloscope but I do it on the first occasion.
Click to expand...

Any chance for a scheme regarding how you connect the parts (power related, amplifier/signal related) together?
It would help to avoid mistakes and unwanted noises.

I rewired my unit, ground star, still have a kind of strong noise, likely an oscillation/saturation, even if no input signal.
 
K

knauf1919

Member
Joined 2015
It can be induction from the transformer ...
Screen it but you have to be careful that the screen is not in galvanic contact with the rest of the housing.
The heat radiator may also require a grounding connection. Possible, but may be indicated in certain situations.
It is difficult to find the exact solution since we do not know exactly how the wiring is routed, how the pcb is designed, etc., etc.
Remove the electronic assembly from the housing and reconfigure the connections. Put the transformer away ...
 
C

csample

Member
Joined 2017
r_jik45 said:
Do you mean that you are using a single 21VDC instead of the double 25VDC to power the amplifier?
Click to expand...

Yes, in the end I did combine the independent DC supplies to a single supply that was 21VDC. I don't know how much of a difference the dual vs. single supply has on the sound quality, but since they are sharing the same transformer in my build it may not matter much. If I were starting over I would use a higher voltage transformer 20VAC and larger capacitors in the CRCRC filter. I added the resistors to my power supply to create the CRCRC filter and it made a significant reduction in noise, but lowered the output voltage as well.

Chas
 
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