Well, posting this after Borkos superb PCBs 
will make me ridiculous at the face of the whole DIY community... 
As an exercice, I tried to copy - shame on me - Admirable Nelson's FW PCB and I am not very satisfied with the result.
Especially the connection between Q5 and input Jfet seems less than convincing on my layout, but my weeny brain cannot find a better way.
Any Idea ...?
Or should I best give up?
Manu
will make me ridiculous at the face of the whole DIY community... As an exercice, I tried to copy - shame on me - Admirable Nelson's FW PCB and I am not very satisfied with the result.
Especially the connection between Q5 and input Jfet seems less than convincing on my layout, but my weeny brain cannot find a better way.
Any Idea ...?
Or should I best give up?
Manu
Manu said:Well, posting this after Borkos superb PCBs
As an exercice, I tried to copy - shame on me - Admirable Nelson's FW PCB and I am not very satisfied with the result.
Especially the connection between Q5 and input Jfet seems less than convincing on my layout, but my weeny brain cannot find a better way.
Any Idea ...?
Or should I best give up?
Manu
I like them
YGFM
jacco vermeulen said:
Jacco that was very cruel of you
Few days ago I`ve seen one of mine beginner`s post and I`ve blushed
My english is a bit better now, I hope but more important I made a good progress in audio electronics, made my Aleph variation "Krypton": http://www.diyaudio.com/forums/showthread.php?s=&threadid=109097&highlight=
and I`m now deep in developing my low feedback class a hybrid amplifier and I`m happy abou it
Cheers!
Borko.
> but if I need more power , how do I do ?
If you consider the dissipation on each MOSFET, they are at 24V 1.3A bias -> about 30W. I would not advise you to go beyond that. So more power always means more MOSFETs.
The maximum output is designed at about 20V 2.6A, i.e. optimised for 8ohm load.
If you have a high impedance speaker, you need more drive voltage. Probably easiest is to drive 2x F5 as bridged amps feeding one speaker using balanced input. Maximum power is now optimised for 16 ohm load.
If you have a low impedance speaker, you need more current rather than voltage. You can of course start paralleling matched output devices (e.g. using 2 pairs of MOSFETs will give maximum power at 4 ohm). But paralleling MOSFETs will change the frequency dependent characteristics of the amplifier.
Patrick
If you consider the dissipation on each MOSFET, they are at 24V 1.3A bias -> about 30W. I would not advise you to go beyond that. So more power always means more MOSFETs.
The maximum output is designed at about 20V 2.6A, i.e. optimised for 8ohm load.
If you have a high impedance speaker, you need more drive voltage. Probably easiest is to drive 2x F5 as bridged amps feeding one speaker using balanced input. Maximum power is now optimised for 16 ohm load.
If you have a low impedance speaker, you need more current rather than voltage. You can of course start paralleling matched output devices (e.g. using 2 pairs of MOSFETs will give maximum power at 4 ohm). But paralleling MOSFETs will change the frequency dependent characteristics of the amplifier.
Patrick