Aleph-x hot source resistor

globalweb · 17th July 2007, 02:30 PM

Hi

I’m half through starting up my Aleph-x (100 w). The problem I have right now is one of my source resistors is getting to hot, over 90 C. Voltage over them, its four resistors is if I remember it correctly 0.54 V. I’m not with the amplifier right now.
I’m sure the solution is out there and I’ve spent yesterday going over treads and I’m going to look for it. But if you know what the solution is it would help me a lot.
So far I have come up with the following possible faults.

- Problem with the PCB. I don’t think so because I’m using this board: http://www.kk-pcb.com/amps.html . It should be ok.
- A broken mosfet- hopefully not. I don’t want to resolder it again for the fifth or tenth time.
- Badly matched mosfet- hopefully not. The voltage over the source resistors are the same.
- Maybe there something with the bias current- I haven’t looked in to that yet.
- Broken silpad
- Bad soldering

Maybe all the source resistors have more then 90 C. I have to look in to that.
Anyway it’s not ok.

I have more question but I think I’ll leave it for later.

Magura · 17th July 2007, 02:33 PM

90C for a power resistor is not all that hot....

Magura

globalweb · 17th July 2007, 06:46 PM

The transistor was 75 C. Much hotter then the others.

Magura · 17th July 2007, 10:21 PM

then try replacing the fet that runs warmer, but keep the initial installed fet to be able to put it back if there is no change.

Magura

tze-hao yen · 18th July 2007, 03:37 PM

one time i did the some mistake
i wire the g directly to the resistor and the resistor got hot so you can try to find out about the wireing you have

globalweb · 19th July 2007, 02:15 PM

Right now I’m waiting for a new PCB. The old one has been re soldered too many times.

globalweb · 19th July 2007, 02:26 PM

Right now I’m waiting for a new PCB. The old one has been re soldered too many times.

17th July 2007, 02:30 PM	#1
globalweb diyAudio Member Join Date: Sep 2006	Aleph-x hot source resistor Hi I’m half through starting up my Aleph-x (100 w). The problem I have right now is one of my source resistors is getting to hot, over 90 C. Voltage over them, its four resistors is if I remember it correctly 0.54 V. I’m not with the amplifier right now. I’m sure the solution is out there and I’ve spent yesterday going over treads and I’m going to look for it. But if you know what the solution is it would help me a lot. So far I have come up with the following possible faults. - Problem with the PCB. I don’t think so because I’m using this board: http://www.kk-pcb.com/amps.html . It should be ok. - A broken mosfet- hopefully not. I don’t want to resolder it again for the fifth or tenth time. - Badly matched mosfet- hopefully not. The voltage over the source resistors are the same. - Maybe there something with the bias current- I haven’t looked in to that yet. - Broken silpad - Bad soldering Maybe all the source resistors have more then 90 C. I have to look in to that. Anyway it’s not ok. I have more question but I think I’ll leave it for later.

17th July 2007, 02:33 PM	#2
Magura diyAudio Member Join Date: Oct 2003 Location: Denmark, Viborg	90C for a power resistor is not all that hot.... Magura __________________ Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com

17th July 2007, 10:21 PM	#4
Magura diyAudio Member Join Date: Oct 2003 Location: Denmark, Viborg	then try replacing the fet that runs warmer, but keep the initial installed fet to be able to put it back if there is no change. Magura __________________ Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com

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17th July 2007, 06:46 PM	#3
globalweb diyAudio Member Join Date: Sep 2006	The transistor was 75 C. Much hotter then the others.

18th July 2007, 03:37 PM	#5
tze-hao yen diyAudio Member Join Date: Jul 2004 Location: brooklyn	one time i did the some mistake i wire the g directly to the resistor and the resistor got hot so you can try to find out about the wireing you have

19th July 2007, 02:15 PM	#6
globalweb diyAudio Member Join Date: Sep 2006	Right now I’m waiting for a new PCB. The old one has been re soldered too many times.

19th July 2007, 02:26 PM	#7
globalweb diyAudio Member Join Date: Sep 2006	Right now I’m waiting for a new PCB. The old one has been re soldered too many times.

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