My Dream Aleph 2 Coming True - Page 11

AudioSan · 29th October 2010, 08:43 PM

Quote:

Originally Posted by BobEllis

Sounds like Z5 is backwards assuming that it is the zener in the CCS and you meant to say .68V not mV.

+1. if your z5=d3 on kristians PCBs.

AudioSan · 29th October 2010, 08:45 PM

it is time to build the other channel. so you can switch

JPDuarte · 29th October 2010, 09:18 PM

Hello Bob ,here is the picture that looks fine for me._MG_2754.jpg

Bill Fuss · 29th October 2010, 10:12 PM

It is hard to help with out the schematic you are using and where you are taking voltage measurements.

What are your source resistor drops.

Is the DC offset plus or minus.

Who's PCBs are you using, have they been proven.

BobEllis · 10:24 PM

Which end of the zener connects to the positive rail? Should be the cathode (band)

What is the resistance from the zener anode to ground or negative rail, depending on which you use?

What is the voltage between the CCS mosfet Source and the positive rail?

We're trying to be sure the CCS is working before we worry about the differential pair.

Measure the voltage referenced to ground at both ends of the zener, all three pins of the CCS IRF9610

JPDuarte · 29th October 2010, 11:21 PM

Quote:

Originally Posted by Bill Fuss

It is hard to help with out the schematic you are using and where you are taking voltage measurements.

What are your source resistor drops.

Is the DC offset plus or minus.

Who's PCBs are you using, have they been proven.

1- Not sure about this, but measured across source resistor 0v. 2- Minus (6.40) Output + should be isolated from ground? 3- Brian GT. aleph2 Layout.gif

JPDuarte · 11:37 PM

Quote:

Originally Posted by BobEllis

Which end of the zener connects to the positive rail? Should be the cathode (band)

What is the resistance from the zener anode to ground or negative rail, depending on which you use?

What is the voltage between the CCS mosfet Source and the positive rail?

We're trying to be sure the CCS is working before we worry about the differential pair.

Measure the voltage referenced to ground at both ends of the zener, all three pins of the CCS IRF9610

Yes, Cathode. The resistance was 0.00 . I was measuring from source point to +Vcc 0.9 going down and when reach 0.4-0.5 after more or less 5 mins started reading 283mv.

BobEllis · 29th October 2010, 11:45 PM

OK, I have no idea what you measured, but lets start here:

What is the voltage across R13? This should be rail-9.1.

What is the voltage across R14? Should be ~4V

What is the voltage to ground at Q1 and Q2 source pins? Should be ~4V

Bill Fuss · 29th October 2010, 11:52 PM

Well, I can tell you that your board is not a BrianGT board.

Bob, if you're using the manual can you email it to me. That's one I don't have.

BobEllis · 29th October 2010, 11:57 PM

Bill, I'm just working off the board image and imagining the schematic.

Not Brian's latest board, but may be an early version.

29th October 2010, 10:21 PM	#105
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	Which end of the zener connects to the positive rail? Should be the cathode (band) What is the resistance from the zener anode to ground or negative rail, depending on which you use? What is the voltage between the CCS mosfet Source and the positive rail? We're trying to be sure the CCS is working before we worry about the differential pair. Measure the voltage referenced to ground at both ends of the zener, all three pins of the CCS IRF9610 Last edited by BobEllis; 29th October 2010 at 10:24 PM.

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29th October 2010, 08:45 PM	#102
AudioSan diyAudio Member Join Date: Feb 2009 Location: Trondheim	it is time to build the other channel. so you can switch

29th October 2010, 09:18 PM	#103
JPDuarte diyAudio Member Join Date: Jan 2010 Location: Providence. RI	Hello Bob ,here is the picture that looks fine for me._MG_2754.jpg

29th October 2010, 10:12 PM	#104
Bill Fuss RIP Join Date: Oct 2005 Location: Central Florida	It is hard to help with out the schematic you are using and where you are taking voltage measurements. What are your source resistor drops. Is the DC offset plus or minus. Who's PCBs are you using, have they been proven.

29th October 2010, 11:45 PM	#108
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	OK, I have no idea what you measured, but lets start here: What is the voltage across R13? This should be rail-9.1. What is the voltage across R14? Should be ~4V What is the voltage to ground at Q1 and Q2 source pins? Should be ~4V

29th October 2010, 11:52 PM	#109
Bill Fuss RIP Join Date: Oct 2005 Location: Central Florida	Well, I can tell you that your board is not a BrianGT board. Bob, if you're using the manual can you email it to me. That's one I don't have.

29th October 2010, 11:57 PM	#110
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	Bill, I'm just working off the board image and imagining the schematic. Not Brian's latest board, but may be an early version.