My MOSFET amplifier designed for music

[Mooly]

Pleased to hear all is good so far...

 

[thimios]

Farther process,testing using +/-35v.
Two 18R/10W resistors instead of fuses.
Input shorted.
Out is open,no load.
Underbiased. 159mV throu 18ohm/10w.
Offset =5mV I think because Vzener=10v still not 12v.
Amplifier is rock stable again!

 

[thimios]

+/-35v,no protective resistors,fuses in situ.
Bias adjusted for 13mV/0.22ohm=0.059A or 59mA.
Still no smoke,no smell.
I think that is time for cheap speakers connection.
I will connect in series with 10.000uf cap.Yes i will try to keep cheap speakers safe for other amplifiers checking!
Next step,using a pair of more expencive speakers....with caps again.
Finall step,+/-45v.
Stay tuned!

 

[Hylle]

If I want to build this amp. Does somebody (preferably in EU), I am in Denmark) have spare PCB´s I can buy. I am interested in using two pairs of output mosfets, since my powersupply will probably end up, around +/- 45-50VDC.

 

[Mooly]

Still no smoke,no smell.

So all still looking good...

I will connect in series with 10.000uf cap.

You're worse than me

 

[thimios]

So all still looking good...


You're worse than me

Yes,I don't afford more destroyed speakers.💣
Singing in stereo!
Please do not ask for impressions,wait the for the next step😉

 

[thimios]

I want to push this a little harder..💣
Connected with better speakers(caps in series of course)
Ok man,I think that I can stamp this as ..TESTED!
Up to now is absolutely stable,no surprises,no smoke no smell no heat,only lovely dynamic music.
To be continued 🤣

 

[Mooly]

Up to now is absolutely stable,no surprises,no smoke no smell no heat,only lovely dynamic music.

Well that is good

To be continued

Could be a long wait because you'll probably just want to keep listening to it......

 

[thimios]

Need to clarify something not to get troubles in others.
In published photos seems that compensation cap C7=22pf is empty.
It isn't!
Because I haven't any through hole type in stock,I have used an smd in the printed side.

 

[thimios]

Final test.+/-45v.
Yes,it is rock stable again.
I want to mention that it isn't a good option to use a lower voltage power supply than +/-45v.
If you will use a lower voltage like +/-35v you will expect high distortion playing near to clip levels.

 

[Mooly]

You should be able to get around 35 to 40 watts rms into 8 ohm on the lower supply.

Pleased to hear it's all good so far

 

[thimios]

Now it is time for oscilloscope test.
Sinusoidal set.

 

[thimios]

+/-45v bias100mA

 

[thimios]

Square wave

 

[Mooly]

That's all looking good to me. What's next? trying it on your main speakers?

 

[thimios]

That's all looking good to me. What's next? trying it on your main speakers?

Hi Mooly next will become THD measurements.
I like a complete test!
In the meantime I will prepare new speakers.
The Asathor published here in DIY.
https://www.diyaudio.com/community/threads/asathor-a-jbl-4367-clone.367215/page-20#post-7175826

 

[Mooly]

OK then.

We're just all waiting for you to listen to it and go OH WOW

 

[Salas]

Is that negative base edge oscillation in #1,313 last picture (input 560mV clip) normally expected?

 

[thimios]

Is that negative base edge oscillation in #1,313 last picture (input 560mV clip) normally expected?

Hi salas,this is my question too.
In any case I must clarify that I need to repeat this measurement connecting a thiele circuit .
I have to repeat this measurement because no thiele circuit was used.

 

[thimios]

A thiele circuit added,no difference.