Help me please, problem with my ALEPH 5

SNOWCRAB · 20th January 2009, 05:44 AM

Hello everybody,

For some time I have a problem with my 5 ALEPH
(PCB DESIGN).
The right channel, works with a stifled and distorted sound.
I placed a protective kit speaker
against the DC current that goes into default.
Can someone guide me in my troubleshooting?

Best regards.

Thierry BASSAL.

SNOWCRAB · 20th January 2009, 11:58 PM

Hi

Last night i made some tests (see original N PASS Schématic)

OFFSET : 35,2 V

Tension between MOSFET Source Résistor

R41 : 0,61 V
R41 : 0,58 V
R42 : 0,60 V
R66 : 0,58 V
R65 : 0,58 V
R64 : 0,58 V

It must be ok

Tension between INPUT MOSFET Résistor

R11 : 4,83 V it must be ok
R14 : 8,40 V (it seems high ?)

Dont you feel there is a problem with Q1 ?

Regards

Thierry

MEGA-amp · 21st January 2009, 12:45 AM

Just to be safe, I'd re-match and install a new pair Q1, Q2. According to Aleph 5 schema, you should have 4-5 volts across R14.

-john

Bill Fuss · 24th January 2009, 01:07 PM

Looks like Q2 is probably open or bad solder joint. As John said, replace Q1 and Q2 with a new matched pair unless you find a fault in your wiring-soldering.
Bill

SNOWCRAB · 25th January 2009, 03:28 PM

Hello,

According to pass lab design,

I replaced Q1 - Q 2 - Q 3 with new matched IRF9610.

New tests :

V - : - 39 V
V+ : + 39 V

R11 : 4,78 V
R14 : 5,10 V
R40 : 0,61 V
R41 : 0,59 V
R42 : 0,61 V
R64 : 0,60 V
R65 : 0,58 V
R66 : 0,58 V
Z5 : 8,68 V

OFFSET : 100 mV

The sound is always distorded and stifled.

I am lost ...

Thierry.

Bill Fuss · 25th January 2009, 05:46 PM

All your measurements look OK. If one channel works compare more component measurements between channels. Check the components values, look for bad solder joints, look for wiring mistakes, check your pinouts on semiconductors.
Bill

MEGA-amp · 26th January 2009, 07:24 PM

I know it may be trivial; but have you tried swapping the inputs from your source and/or preamp?

20th January 2009, 05:44 AM	#1
SNOWCRAB diyAudio Member Join Date: Jan 2004 Location: NANTES - FRANCE	Help me please, problem with my ALEPH 5 Hello everybody, For some time I have a problem with my 5 ALEPH (PCB DESIGN). The right channel, works with a stifled and distorted sound. I placed a protective kit speaker against the DC current that goes into default. Can someone guide me in my troubleshooting? Best regards. Thierry BASSAL.

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20th January 2009, 11:58 PM	#2
SNOWCRAB diyAudio Member Join Date: Jan 2004 Location: NANTES - FRANCE	Hi Last night i made some tests (see original N PASS Schématic) OFFSET : 35,2 V Tension between MOSFET Source Résistor R41 : 0,61 V R41 : 0,58 V R42 : 0,60 V R66 : 0,58 V R65 : 0,58 V R64 : 0,58 V It must be ok Tension between INPUT MOSFET Résistor R11 : 4,83 V it must be ok R14 : 8,40 V (it seems high ?) Dont you feel there is a problem with Q1 ? Regards Thierry

21st January 2009, 12:45 AM	#3
MEGA-amp diyAudio Member Join Date: Oct 2003 Location: Newington, CT	Just to be safe, I'd re-match and install a new pair Q1, Q2. According to Aleph 5 schema, you should have 4-5 volts across R14. -john

24th January 2009, 01:07 PM	#4
Bill Fuss RIP Join Date: Oct 2005 Location: Central Florida	Looks like Q2 is probably open or bad solder joint. As John said, replace Q1 and Q2 with a new matched pair unless you find a fault in your wiring-soldering. Bill

25th January 2009, 03:28 PM	#5
SNOWCRAB diyAudio Member Join Date: Jan 2004 Location: NANTES - FRANCE	Hello, According to pass lab design, I replaced Q1 - Q 2 - Q 3 with new matched IRF9610. New tests : V - : - 39 V V+ : + 39 V R11 : 4,78 V R14 : 5,10 V R40 : 0,61 V R41 : 0,59 V R42 : 0,61 V R64 : 0,60 V R65 : 0,58 V R66 : 0,58 V Z5 : 8,68 V OFFSET : 100 mV The sound is always distorded and stifled. I am lost ... Thierry.

25th January 2009, 05:46 PM	#6
Bill Fuss RIP Join Date: Oct 2005 Location: Central Florida	All your measurements look OK. If one channel works compare more component measurements between channels. Check the components values, look for bad solder joints, look for wiring mistakes, check your pinouts on semiconductors. Bill

26th January 2009, 07:24 PM	#7
MEGA-amp diyAudio Member Join Date: Oct 2003 Location: Newington, CT	I know it may be trivial; but have you tried swapping the inputs from your source and/or preamp?

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