2DIFFET amplifier

[pinnocchio]

received my PCBs

Thanks!
Do

 

[OnAudio]

Happy new year members .

Hi Pinnocchio, hope you have set up your amp

kind regards,

Harrison.

 

[pinnocchio]

Happy New Year to you too!

Not yet, I'm working on a project for now but will start in a few weeks. It will get done like the Symef which my friend really likes btw!

Ciao!
Do

 

[OnAudio]

With a build like this, its beautiful in and out

Happy New Year to you too!

Not yet, I'm working on a project for now but will start in a few weeks. It will get done like the Symef which my friend really likes btw!

Ciao!
Do

 

[quan]

Hi , has any one build their 2diffet as yet?. Just a couple of questions _ re setting bias procedure?, input differential pair- would matching by Hfe be sufficient? The output Mosfets - do they need to be match by Vgs?.
Quan

 

[jkuetemann]

I have a set of boards, just getting through some other commitments before I can get going on this one.

 

[quan]

Hi Jason, there is no build guide , just a schematic and i am planning to proceed as prior.
Quan

 

[tvrgeek]

Harrison,take a look at the specs of IRFP9140 is matching much better with the IRFP240

Ah, that makes sense. I have seen that as a pair and had not had the time to see why.

 

[jkuetemann]

That is what I'm going to use on these boards too, the IRFP240 and IRFP9140. They are much more complimentary than most verticals you could pair up, save for the lower voltage rating of the IRFP9140.

 

[OnAudio]

setting bias procedure?,

Use 100ma. Note the bias compensation scheme is cute .

input differential pair- would matching by Hfe be sufficient?

That will get you slightly better specs

The output Mosfets - do they need to be match by Vgs?.
Quan

That will get you better current sharing

 

[quan]

2DIFFET

OK THANKS. I am waiting for my parts to arrive to complete the build. Regard setting the bias can you advise?.
Quan

 

[OnAudio]

Hi Quan,

Before powering up, ensure R26 is at max resistance . Let the amp sit then gradually adjust bias in small increments spaced by sits, till you get about 100mA flowing across each source output resistor.

kind regards,

Harrison.

OK THANKS. I am waiting for my parts to arrive to complete the build. Regard setting the bias can you advise?.
Quan

 

[quan]

Thank you . Will keep you posted once the parts arrives.
Quan

 

[OnAudio]

Looking forward

kind regards,

Harrison.

Thank you . Will keep you posted once the parts arrives.
Quan

 

[OnAudio]

Whose ready to share

 

[OnAudio]

Has anyone finished their build yet ? Your experiences, comments, suggestions, complaints, commendations, worries, concerns and chocolate welcome

 

[OnAudio]

If your curious about this amplifier and would like to build and test drive it for us and the only thing holding you back is a PCB kindly drop a PM. Schematic: http://www.diyaudio.com/forums/solid-state/239753-2diffet-amplifier-4.html#post3642421 . BOM: http://www.diyaudio.com/forums/solid-state/239753-2diffet-amplifier-4.html#post3728062

 

[OnAudio]

Here is a picture.

 

[OnAudio]

Got 14 to spare. One per member (one channel). You can paypal shipping charges (around $8) once you receive them. However if you submit your results in one month after you receive them, then shipping is waived...

 

[OnAudio]

A couple of years later, whatever happened to your builds