It's funny to me, or it goes against my preconceptions, that all of these amp projects seem to include parts that are made out of nearly pure unobtainium. Power Jfets, lateral power mosfets, matched of course. I had this idea that I was going to pull out my mouser catalog...instead I'm buying Buz900 mosfets from some guy in London, and getting other rare parts through the goodness of fellow members. Thanks, guys. What a fun community of whackos.
@Peter: do I see correctly that you use Common-Cathode diodes in dual package (2 diodes per TO-247) for the psu-board?
May I ask why you stick with 4 diodes then (3 would be sufficient?)? My problem is at the moment to locate dual common-cathode diodes; so far I could only find one from ST (the fancy diodes are usually single package=2 pins and the standard recovery duals have different pin out).
All the best, Hannes
May I ask why you stick with 4 diodes then (3 would be sufficient?)? My problem is at the moment to locate dual common-cathode diodes; so far I could only find one from ST (the fancy diodes are usually single package=2 pins and the standard recovery duals have different pin out).
All the best, Hannes
Peter,
What pad size will there be for C8? Judging from the image posted some time ago it looks like 5-6 mm.
It would be nice to fit something like RIFA PHE426/450 but if it’s 5-6mm size will be a problem. What part did you have in mind when you designed?
Great work and many thanks for the hours spent designing, not to mention the distribution of the PCB's!
BR
Mikael
What pad size will there be for C8? Judging from the image posted some time ago it looks like 5-6 mm.
It would be nice to fit something like RIFA PHE426/450 but if it’s 5-6mm size will be a problem. What part did you have in mind when you designed?
Great work and many thanks for the hours spent designing, not to mention the distribution of the PCB's!
BR
Mikael
traw said:
I'm immersed in the red wine came from the downunder at this time of writing.
Well well . . .
If I try to peep into Papa's mind, it seems that P1 is for the dc voltage of about 18.5V at the centre of voltage swing while P2 is there for bias current gain adjustment.
If any one wants to argue, who could stop it . . .
ah ha... got one up and running (home made etch similar to PD's layout - too anxious and OCD)
my rail voltage is 46 unloaded, 43 loaded 500 va.
easy nuff to adjust P1 for drain on Q2 to be midpoint... drain on power jfet varies when adjust, rise for moment then falls back to 2.9 or so. Using the stock 2+2+2.7 parallel network. Should I up the network resistance or lower?
On P2 adjustment... what should i shoot for? Look for what current where? What looking across the resistor network but imagine maybe look somewhere else.
my rail voltage is 46 unloaded, 43 loaded 500 va.
easy nuff to adjust P1 for drain on Q2 to be midpoint... drain on power jfet varies when adjust, rise for moment then falls back to 2.9 or so. Using the stock 2+2+2.7 parallel network. Should I up the network resistance or lower?
On P2 adjustment... what should i shoot for? Look for what current where? What looking across the resistor network but imagine maybe look somewhere else.
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