Banned
Joined 2002
jleaman said:
I would agree that Jason is simply too lazy! Besides papa, Steen and I are the only who have said we have built the thing. Whilst steen has no problem with heat in his chassis, I have provided plenty of information on the heat produced by my clone.
Just read this thread and your inbox! For those who doesn't have my comments in their personal inbox, just scroll back 25 posts or so and see what I write.
Mr. Pass,
For a DIY montage (100W ouput into 2 ohm load), is it preferable to double the number of pair of Mosfets and size of heatsink or to use the diagram of the page 9 (parallel mono connections).
What is the maximal + - Vcc of PSU admissible by the F4 with the 2SK370/2SJ108 if one increases the size of heatsink and maybe also, increases the number of pairs of Mosfet?
Thank you for your answers
Darry
For a DIY montage (100W ouput into 2 ohm load), is it preferable to double the number of pair of Mosfets and size of heatsink or to use the diagram of the page 9 (parallel mono connections).
What is the maximal + - Vcc of PSU admissible by the F4 with the 2SK370/2SJ108 if one increases the size of heatsink and maybe also, increases the number of pairs of Mosfet?
Thank you for your answers
Darry
I don't think it is advisable to increase the voltage across the jfet pair too much - they are running close to the specs. If you need larger voltage swing I would recommend running balanced, but with 2ohm speakers I guess you need current more than anything.
You can easily turn up the current if you have suitable heatsinks. If you run single ended mono you should be able to get at voltage swing of +/-20V and with increased bias current, you should be able to get 100W - I think....
You can easily turn up the current if you have suitable heatsinks. If you run single ended mono you should be able to get at voltage swing of +/-20V and with increased bias current, you should be able to get 100W - I think....
Why wait - you guys will just start second guessing me in
the meantime.
www.passlabs.com/np/F4R0.pdf
This version bootstraps the front end so that the JFETs only
see about 1/2 the voltage swing. It improves THD very slightly,
gets a tad more output swing, and it also extends the bandwidth
a bit. With a proper setup, I get about -3dB at 1 MHz, with a
very good looking 100 KHz square wave.
the meantime.
www.passlabs.com/np/F4R0.pdf
This version bootstraps the front end so that the JFETs only
see about 1/2 the voltage swing. It improves THD very slightly,
gets a tad more output swing, and it also extends the bandwidth
a bit. With a proper setup, I get about -3dB at 1 MHz, with a
very good looking 100 KHz square wave.
Great work (like always) Mr Pass
Modifications added - I almost redesigned PCB. I will probably place sources in PDF format for a minute.
schematic f4_r0
Modifications added - I almost redesigned PCB. I will probably place sources in PDF format for a minute.
schematic f4_r0
Attachments
Not so fast - I knew there was a reason I was going to wait
a day - reload the schematic and check the connections on
D3 and D4.
www.passlabs.com/np/F4R0.pdf
a day - reload the schematic and check the connections on
D3 and D4.
www.passlabs.com/np/F4R0.pdf
Banned
Joined 2002
veteran said:
I hope i have your permission to print this board to test it out, ?
WoW! So are you saying we can get into say +-40v or so, assuming adequate cooling? Where would that put us - 50wpch or so of class A?
Thanks Mr Pass
OH, and before I forget - could you please make any more refinements before I complete mine
because if you do it afterwards I may 
. Not a pretty sight.