Nice work Vunce and your initial impressions are very encouraging indeed. Can I ask if you are going to package it in a nice enclosure to finish it off?
Can't wait to start on mine, boards arriving today and parts I have ordered will be here on Monday.
It sounds like you should be proud of your work Borko.
Looking forward to your listening impressions with that more than difficult load for this type and size of amp Vunce.
Can't wait to start on mine, boards arriving today and parts I have ordered will be here on Monday.
It sounds like you should be proud of your work Borko.
Looking forward to your listening impressions with that more than difficult load for this type and size of amp Vunce.
Thanks Gary 
Yes, I will finish it off. The amp is currently standing upright. Picture lying it down, the makerbeam rails that are attached to both sides of the heat sinks are going to be the attachment points for the top and bottom aluminum panels. The rear panel, approximately 11” wide, will attach to the meaty sections of heatsinks with fins exposed. The front panel will span the entire width approximately 17”. So ultimately, it will look like a conventional type chassis with the front panel clean, heat sink fins visible from the top, sides, bottom and rear.
That’s the plan......but you know how the best laid plans go
Happy Building!!
Cheers!
Yes, I will finish it off. The amp is currently standing upright. Picture lying it down, the makerbeam rails that are attached to both sides of the heat sinks are going to be the attachment points for the top and bottom aluminum panels. The rear panel, approximately 11” wide, will attach to the meaty sections of heatsinks with fins exposed. The front panel will span the entire width approximately 17”. So ultimately, it will look like a conventional type chassis with the front panel clean, heat sink fins visible from the top, sides, bottom and rear.
That’s the plan......but you know how the best laid plans go
Happy Building!!
Cheers!
I use this board as a test bed, it has a Fo-Felix AC filter and an old DIYA store softstart circuit onboard.
GB: Round #6; Fo-Felix AC Filter
GB: Round #6; Fo-Felix AC Filter
Didn't try that with the amplifier, don't have a time but I guess it could be done...
The front panel knobs will have to be avoided in that case. You can't change feedback etc., on the fly as it would affect offset.
Thank you for your feedback, Bogdan. I just have a thing for bipolar cfp, like some others do for mosfets.
About the feedback cap and bias: that is a dilemma, with a low value jfet source resistor one needs a pretty big capacitor, and I would rather not have that. We will see what happens with bias in a real circuit.
What simulation model do you use for the 2sk932? I made one up using the datasheet, but is probably not very good. And I am afraid it was not working at all in the spice file that I posted above, so here it comes again:
About the feedback cap and bias: that is a dilemma, with a low value jfet source resistor one needs a pretty big capacitor, and I would rather not have that. We will see what happens with bias in a real circuit.
What simulation model do you use for the 2sk932? I made one up using the datasheet, but is probably not very good. And I am afraid it was not working at all in the spice file that I posted above, so here it comes again:
This is an update of the circuit, now it has about 9dB less feedback, I think it sounds better and transient behaviour is lot better, no overshoot on a square wave... The corrections are in red on the schematic, Rs added and C10 and R14 have different values (other end of the R14 is now conected to the output node, not gnd like before).
Cheers, Borko.
Cheers, Borko.
Attachments
What is HP?
Prasi pcb needs litle bit of revision, for updated version, but I can't do it, never worked in eagle, I've done my pcb in Altium..
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Speaker gnd shoud be on the main pcb, not star ground of the amplifier power supply.