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MEGA_amp 23rd August 2006 05:40 PM

ZEN noob question
 
I purchased the Zen board a while ago, and finally got around to populating the board. Everything is original with the exception of a 4.7uF film cap across C6, a 10uF cap across C3, and a .22R 10 watt for R1. I eliminated C1 and C2, because my supply consists of 392KuF with 2.2 mH coils, unloaded it provides 53 volts (I'm using very large heatsinks, hopefully it wont blow up). Now, I remember Nelson suggests setting P1 to half the rail voltage, what two points do I measure from?


Thanks
John

Nelson Pass 23rd August 2006 08:41 PM

From Ground to V+, or between the Source Pins of the two
Mosfets (close enough).

MEGA_amp 23rd August 2006 08:50 PM

Thanks Nelson!! Still waiting on the FETs, pics soon to follow.

johndiy 24th August 2006 06:44 AM

umm i am new here what was there i wanted to ask
umm Nelson Pass is this the guy who is got articles
published in magazines like audioxpress or is a fake
you guys made up!umm cause it would be awesome
you know chat with him about fusistors and stuff

john

Sonusthree 24th August 2006 10:22 AM

Yes John he is the real Mr Pass. :nod:

Babowana 24th August 2006 10:27 AM

Quote:

Originally posted by johndiy



umm i am new here what was there i wanted to ask
umm Nelson Pass is this the guy who is got articles
published in magazines like audioxpress or is a fake
you guys made up!umm cause it would be awesome
you know chat with him about fusistors and stuff



a-man . . . enjoy the meal . . .

johndiy 25th August 2006 12:15 AM

you know Zen is awesome!
umm what happens if i change the active load with
a passive one, will it sound better, what type of fet
is better for zen L-fet or V-fet?

john

johndiy 25th August 2006 01:06 AM

2 Attachment(s)
need help with zen attached
umm is feedback equal to r3/r1 or r3/r2
if it is r3/r1 r1 should be low value right? how low?

is this a good zen?

john

Babowana 25th August 2006 03:03 AM

Quote:

Originally posted by johndiy


need help with zen attached
umm is feedback equal to r3/r1 or r3/r2
if it is r3/r1 r1 should be low value right? how low?


It seems that all r1/2/3 are involved in the feedback . . .
Gain approximately (r2xr3)/(r1x(r1+r2)) . . . ??? hmm . . .

MEGA_amp 6th September 2006 10:44 PM

fired up the zen, sounded great for a few minutes...The solder from the Drain of Q2 keeps melting off, and R1 gave up the ghost. Could this happen if Q3 is in backwards. Q2 blew on the left channel as well, but R1 is intact. It worked fine yesterday, the only change I made was to the power supply; I paralleled the two 2.2mH inductors, in the series config, they nearly melted.

R1 .22 10W
Q1 IRFP140
Q2 IRFP9140
45V rails




John


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