zen lightenment!

[Zen Mod]

19Vdc is too low

you must have at least 14-15V across mosfet , to have it anywhere near linear region

 

[oks81]

Ok! 🙂
It`s just so easy put together with few parts, that it would be fun to build!

Just thinking out loud here...:

I`m having 300VA trafo 2x15v sec. so can also get out 38v.
Find that the original 110v 300w bulb is 40ohm.
Article says 12v on Drain for Mosfet -> 28v over bulb? -> Bias 0,7A? (With 40v PSU)

Transforming into two 24v bulbs in series they will need to be about 72w each?

Am I on deep water or....? 🙂

Can I use the 300VA trafo or should I forget it all?

 

[Circlomanen]

I am running an IRFP150 at 1,0 amp and 10 volts D-S, with only 1,0 ohm source degeneration, and it works just fine. I don´t get more then 1,7 watts from the amp, but with very efficient BIB loudspeakers it enough for me.

The amp sounds very clean and precise. I can´t hear any distortion or lack of definition.

regards,
Johannes

 

[oks81]

Aha! So you mean it should be possible running at 19V?
What V and VA is your PSU Circlomanen?
I`m not looking for power, but simplicity and good sound 🙂

 

[Circlomanen]

My transformer is a 10 + 10 volt secondaries (160 VA), rectified it gives 28 volts. I use a capacitance-multiplicator that takes the voltage down to 25,2 volts over the amp circuit. There is a simple 15 ohm power resistor as drain-load (no constant current source).

regards,
Johannes

 

[oks81]

Ok 🙂
And the rest of circuit same as in Fig.5 in article?
(Sorry, can't get picture of figure out here, maybe someone can help?)

 

[Circlomanen]

This is the amp as it is playing now. It is a rats-nest point to point build, to test a no (global) feedback as simple as possible Zen amp.

regards,
Johannes

 

[oks81]

Nice!
Maybe rename it as "Simply Zen" 🙂

 

[oks81]

Also looking at the F2.. maybe also possible to build with bulb instead of the current source section?