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Old 23rd February 2012, 05:59 PM   #2481
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OK I meant matching Idss not Vgs.
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Old 23rd February 2012, 06:04 PM   #2482
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Default FireFlies - well pretty lights

It's almost a shame to put it in a box.
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Old 23rd February 2012, 09:49 PM   #2483
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I've been using the high "unmatched" Idss 2SK170BLs for the current sources for the LEDs. Most of them are running between 8 and 10mA.
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Old 23rd February 2012, 10:05 PM   #2484
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Good choices.
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Old 24th February 2012, 05:47 AM   #2485
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I was a bit surprised at the final voltages.

I suppose I was looking for exactly 10V as the schematic stated, However they are stable and matched at +/- 9.5V.

I'm not familiar with using MOS-FETs in PSUs.
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Old 24th February 2012, 06:18 AM   #2486
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I've just fitted the important Buffer FETs.

Not too bad a result - measurement wise. ~3mV on one channel and <0.5mV on the other. That was with FETs matched to within 0.01mA of each other.

I'll try it sonically this afternoon. Even I have to go to work sometimes.
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Old 24th February 2012, 06:46 AM   #2487
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The jfets working under Vbe only which form the string of five constant current drains lost 25-30% IDSS VS battery test. Hence the leds lost a bit of Vf each is the voltages explanation. Very good voltages as for DCB1, no further tweaks are needed.
If you will mutually swap the 3mV pair jfets there can be a different result for better or worse. But 3mV is mighty fine. You gonna put an all DC scenarios safety capacitor in the output as you said, so any DC becomes a non issue anyway. Happy listening.
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Old 24th February 2012, 08:04 AM   #2488
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Quote:
Originally Posted by dvb-projekt View Post
Thanks for your suggestion, but the problem is also with other interconnects, see Post #2458 . A bit better but not silent...
Still, have a look at what I try to say:
big loop to catch hum.jpg
[I had this similar problem too when I went from 330B mono's to Le Monstre]
It is these two sides of the loop (L/R) that have to be twisted or taped together.

The output impedance of the B1 is not low enough to kill the inductance . . . completely. (A Kondo stage would do slightly better probably)
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Old 24th February 2012, 01:29 PM   #2489
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Quote:
Originally Posted by triode_al View Post
Still, have a look at what I try to say:
Attachment 268244
[I had this similar problem too when I went from 330B mono's to Le Monstre]
It is these two sides of the loop (L/R) that have to be twisted or taped together.

The output impedance of the B1 is not low enough to kill the inductance . . . completely. (A Kondo stage would do slightly better probably)
albert
Hi Albert,

i tried that. A bit better like the Nordost cables i had tried, but the hum is still there...
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Old 24th February 2012, 02:42 PM   #2490
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I'm sorry to say it but I prefer the sound of my B1 clone over that of the DCB1.

I might try the B1 with the SALAS reg to see if it improves matters.

For some reason or other my DCB1 just doesn't sound as "Clean" as the B1.

Before anyone comments, do remember that mine have both got output caps. I've used Mundorf 33uF630V Polyprops with the DCB1 and Obbligato 10uF PIOs with the B1.

My DCB1 is also single sided PCB whereas the B1 is double sided.

PLEASE NOTE - This is NOT a SALAS PCB, it is a homebrew board built using the original artwork.

I've also got very slight HUM which is not present on the B1, this could be down to layout or a faulty component.



One channel is distorting but only as I approach half volume.

Last edited by KatieandDad; 24th February 2012 at 02:54 PM.
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