Zen amp

[Wierd]

Hello

Im planning to build a zen (revisited).
Where Will i find good mosfets, can i use hexfets?
In the past i build a JLH69 class a amp.
These amp is still working.
I wonder if the zen have the same perform as the jlh.

 

[adason]

no two amplifiers perform the same

 

[Wierd]

Ok,

Are they in the same catagorie?

 

[Nelson Pass]

They are both Class A.

 

[Wierd]

Thanks for the replay,

I,m planning to build one.
Is the second (revised) still a good choice to build?

 

[adason]

I build this one few years ago, penultimate with higher power, with all modern transistors. Sounds great.

The Class-A Amplifier Site - JLH Class-A Update

 

[Circlomanen]

Here is a slightly simplified Zen amp with a mu/SRPP dynamic current-source based on a simple cheap 9 volt battery (V2).

With two IRFP054 you get quite low THD.

LTSpice says 0.204% THD @ 6 watt output into 8 ohm load. With real speakers and real reactivity in the load I would be happy with 0.5% measured THD. This SRPP-Zen-amp simulates much better then the stock normal Zen-amp.

With slightly higher voltage over the sensing resistors in the SRPP current-source you get less distortion at lower output-power but the amp will start clipping at slightly lower output-power.

M1 and M2 can be IRFP054, IRFP064, IXYS IXFH110N10P Polar mosfet or similar.
I would without a doubt go with the IXYS mosfet. They sound absolutely superior in simple class A amps in my experience.

Cheers,
Johannes

 

[Wierd]

Hello'

I am now collecting the parts for the Zen (revisited).
It is hard finding the originals.
Can i use another type?
Is it possible using the same type for the upper en down part?

 

[Wierd]

Oeps,

I am asking the info About the mosfetts

 

[Dennis Hui]

OK...I just looked at the Zen revisited article and see that
IRF140 and IRF9140 (TO-3 metal can parts) are shown. You can just use the
current plastic package lead-free versions: IRFP140PBF and IRFP9140PBF.
These should be readily available. (The original Zen article actually
listed the plastic packaged mosfets.)

As drawn, the constant current source in the Zen revisited uses a
P-channel part. Please see the Zen Variation 2 article for a version
with an N-channel mosfet and the modification into an Aleph current source:

https://www.passdiy.com/project/amplifiers/zen-variations-2

Cheers,
Dennis

 

[Wierd]

Dennis,

Thanks for the info.
I indeed can get the plastic versions.
Betters the Alehp current source the original?

 

[moe29]

my ZEN 🙂

i found it a very educational build.