ZEN noob question

MEGA_amp · 23rd August 2006, 06:40 PM

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, 09:41 PM

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

MEGA_amp · 23rd August 2006, 09:50 PM

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

johndiy · 24th August 2006, 07:44 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, 11:22 AM

Yes John he is the real Mr Pass.

Babowana · 24th August 2006, 11:27 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, 01:15 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, 02:06 AM

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, 04:03 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, 11:44 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

23rd August 2006, 06:40 PM	#1
MEGA_amp diyAudio Member Join Date: Oct 2003 Location: Newington, CT	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

24th August 2006, 11:22 AM	#5
Sonusthree diyAudio Member Join Date: Dec 2005 Location: Sussex, UK	Yes John he is the real Mr Pass. __________________ Martin + + =

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23rd August 2006, 09:41 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	From Ground to V+, or between the Source Pins of the two Mosfets (close enough).

23rd August 2006, 09:50 PM	#3
MEGA_amp diyAudio Member Join Date: Oct 2003 Location: Newington, CT	Thanks Nelson!! Still waiting on the FETs, pics soon to follow.

24th August 2006, 07:44 AM	#4
johndiy Banned Join Date: Aug 2006	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

25th August 2006, 01:15 AM	#7
johndiy Banned Join Date: Aug 2006	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

6th September 2006, 11:44 PM	#10
MEGA_amp diyAudio Member Join Date: Oct 2003 Location: Newington, CT	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