ZEN Amplifier Mini with IRF610 as Headphone Amplifier for 32 Ohm

The ZEN Amplifier concept is simple. But it works great.
Here is such an amplifier but with less current and uses IRF610 as MOSFET.
It makes a simple and sweet headphone amp.

Building shouldn't be difficult.
The heatsinking it takes is not so much.
There is some THD, but it is mainly 2nd harmonic.
So, it would be good listening.

The amp is designed for 32 Ohms headphones.
For other impedances it needs tweaking to make it alright.
 

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I don't build.
I have nowhere to be if I should build.
I have all my stuff in a little room where I also have my bed.


Here is the 65 Ohm version.
There wasn't much to change.
Main change is another transistor - IRF520. Gets better data in my simulation.
The relay circuit is also improved. And a couple of resistors.

I only design for no more than 10mW. That is +20dB. That is enough to make your ears hurt .....
 

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Nice job, lineup! I ran into a Mini Zen Headphone Amp board in my stash recently and I like your updates. I have various headphone sets here, Grado, Sennheiser, etc. Could we make this amp with even higher impedance so that it becomes more universal? Maybe some value in between such as 150 Ohm?
 
@bhjazz
This version will work with a bit higher impedances.
I use IRF610 MOSFET.
Distortion is aceptable and I think this will sound good.
Sound is what ZEN amplifiers are built for.

There is a delay on circuit.
But this can be omitted.
 

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@lineup you do know about this one right? https://headwizememorial.wordpress.com/2018/03/11/the-zen-headphone-amplifier/ (I know the schematics are not completely identical, but the basic idea looks the same).

Originally the design was published in English here https://www.diyaudio.com/community/threads/zen-like-headphones-amp.2451/ - so 22 years ago (!) - but maybe it's time for a revival? :cool:
That application uses Aleph Current Source. We can say this is sort of Push-Pull.
This gives lower distortion.
My circuit has little more distortion because it is more simple.
But because it is simple it is easier to build.
 
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@Nisbeth
Your article is from 2016. Was a long time ago.
But you still have your headphones, I imagine.
The latest version is for @bhjazz.
He has several headphones, so we made this version to suit several impedances.
150 Ohm is somewhere in the middle.
Should work with most headphones.

Low distortion is not automatically good sound.
It is some distortion that ca make 'the sound' of an amplifier.
Ask @Nelson Pass - he knows .. :)
 
There is a way to adjust for different gain to suit impedances.
In my circuit there is a resistor R2 = 10 kOhm.
For more gain change it to 6.8 kOhm or even 4.7 kOhm.
For less gain change it to 15 kOhm or even 22 kOhm.
This way my circuit can work with any headphones.