I like the Bulwark design so far. I'm experimenting with a adding little extra (3 dB) gain. I intend to match the Bulwark overall gain with that of the Dreadnought boards that I built. There is a remarkable difference between the Dreadnought and the Bulwark signatures. I'm sure that the Edcor is the major component responsible.
(Reply to Ylab #110 : )
I used a cap rated 35V. In steady-state, I measured a drop of around 9V through R4 (equaling current through the JFETs of approx. 9 mA), so the cap should see something like (36V-9V) / 2 = 13-14V.
It was hard for me to imagine a fault mechanism that would put the full 36V across the cap (Q1 shorted and at the same time, Q2 infinite resistance). Even at start-up, it should not see the full 36V, and if, only very briefly.
So I figured a 35V cap would be safe at this particular position.
Regards, Claas
I used a cap rated 35V. In steady-state, I measured a drop of around 9V through R4 (equaling current through the JFETs of approx. 9 mA), so the cap should see something like (36V-9V) / 2 = 13-14V.
It was hard for me to imagine a fault mechanism that would put the full 36V across the cap (Q1 shorted and at the same time, Q2 infinite resistance). Even at start-up, it should not see the full 36V, and if, only very briefly.
So I figured a 35V cap would be safe at this particular position.
Regards, Claas
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I used a cap rated 35V. In steady-state, I measured a drop of around 9V through R4 (equaling current through the JFETs of approx. 9 mA), so the cap should see something like (36V-9V) / 2 = 13-14V.
It was hard for me to imagine a fault mechanism that would put the full 36V across the cap (Q1 shorted and at the same time, Q2 infinite resistance). Even at start-up, it should not see the full 36V, and if, only very briefly.
So I figured a 35V cap would be safe at this particular position.
Regards, Claas
Great thank you for the explanation!
Hubert
Attached is the final edit of DIY Sony VFET amp pt 2.
Correction of error in power supply schematic.
Thanks you Mr. Pass
Please could we find this mini article link on the First Watt site updated pages ?
Working?
Anybody has finished the build and listens to music? My output stage insists in "non-working", I bridged the input, but the result stays the same, low level, heavy distorted.
They get quite hot, as expected, the voltage between ground and drain of IRF250 is adjusted to 14V. I have to check the cabeling again?
Anybody has finished the build and listens to music? My output stage insists in "non-working", I bridged the input, but the result stays the same, low level, heavy distorted.
They get quite hot, as expected, the voltage between ground and drain of IRF250 is adjusted to 14V. I have to check the cabeling again?
Attachments
No. 176 lives ...
... and is making sweet music
Sweet, clear, 3D, goosebump-inducing, detailed, very engaging, ... some maybe somewhat contradictory terms, but it's not easy to get my head around the music from this amp. Really nice.
It also seems to be doing quite well on complex music, at least on my 100dB/W Fostex widebanders. Have not been able to compare, it's way too early, need to become more familiar with it.
Regards, Claas
... and now, please excuse me, I must listen to some music ...
... and is making sweet music
Sweet, clear, 3D, goosebump-inducing, detailed, very engaging, ... some maybe somewhat contradictory terms, but it's not easy to get my head around the music from this amp. Really nice.
It also seems to be doing quite well on complex music, at least on my 100dB/W Fostex widebanders. Have not been able to compare, it's way too early, need to become more familiar with it.
Regards, Claas
... and now, please excuse me, I must listen to some music ...
Attachments
Nice to have first confirmation of operation in the field.....
AKA The Sh8 works!
Thanks Pop, really, this is very cool. There are a lot of great people in the industry, but I know of no other top dog who tends his flock
so studiously. You are a great sheepdog, though you look like less of one now oh cold chinned one.
JT
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