Brother of Quasi

[quasi]

Conceptualised in the thread "Power Amp Under Development" here is the transistor output stage variant.

http://www.diyaudio.com/forums/showthread.php?postid=946429#post946429

A version has already been built by fellow diy'er Kraft and this thread is dedicated to the development of this version.

Cheers
Quasi

 

[quasi]

The schematic

The schematic is of course very similar. Apart from the output stage other small changes were made to accomodate a workable layout.

Cheers
Q

 

[quasi]

Board Layout - TO3 version

Here is the board layout. It retains the famous U-channel heatsink for the second stage transistors

Please check it before you build.

Cheers
Q

 

[quasi]

And the tracks

Here are the tracks. This board also contains DC detection.

Cheers
Q

 

[poobah]

I hate people that try to be quasi quasi...




NO CIGAR!

 

[Leolabs]

I hate people that try to be quasi quasi...

Why???Because you like to be symmetrical???

 

[edl]

Hi,

Hmmm... Such high power amp without short-circut protection?!
Then it's not intended for PA usage... Then for what?

 

[quasi]

Hi,

Hmmm... Such high power amp without short-circut protection?!
Then it's not intended for PA usage... Then for what?

It is intended as a powerful high quality domestic power amp. The reason for this thread is because there have been requests (forum and email) for a varient of the mos design that used conventional power transistors, particularly TO3 types.

So here it is. Anyone who wants to build it and take advantage of TO3 devices they have laying around may do so. Or they can choose not to.

Cheers
Q

 

[mikeks]

http://www.diyaudio.com/forums/showthread.php?postid=1023742#post1023742

 

[mikeks]

http://www.diyaudio.com/forums/showthread.php?postid=1022628#post1022628

 

[edl]

Hi Quasi,

I see. Thanks for the reply.
I hope my question wasn't insolent.

Have a good work!
Regards,

 

[myhrrhleine]

I hate people that try to be quasi quasi...

Don't let Quasi moto hear you say that!

 

[quasi]

I hate people that try to be quasi quasi...




NO CIGAR!

How how so so ?

 

[quasi]

http://www.diyaudio.com/forums/showthread.php?postid=1023742#post1023742

http://www.diyaudio.com/forums/showthread.php?postid=1022628#post1022628

Is your main concern about the trimpot wiper going o/c?

 

[mikeks]

Is your main concern about the trimpot wiper going o/c?

Yes.

Try shunt regulator below.

Its output impedance is lower than that of most monolithic voltage references.

Consequently, variation in output voltage due to anomalous variation in standing current is virtually nil.

Additionally, your output stage won't fry in the event of the wiper failing open.

 

[quasi]

Error in layout

The layout has some errors. These have been corrected in this attachment.

Cheers
Q

 

[quasi]

and the PDF ....

..

 

[bogdan_borko]

Hi Mikeks! How much money you gained for promoting that circuit?

This morning I opened my washing machine and Mikeks came up and sad: "Try this shunt regulator!"

cheers!

 

[mikeks]

 

[medogrizli]

Compared : this bipolar to mosfet amplifier : what is better to built : Sond qualitiy I mean subject sound qualitiy : Can you describe sifference using word (your ear)



So this bipolar is +/- 70V : This is more than 300W 8ohm : but when yousing mosfets you get less power arond 200W ?

So why usnig dual power supply ? 60V and 70V can I use only 70 V ?

thanks