IRFP9610 Heat Sink Aleph 2 Question (and others) - Page 3

Nicwix · 22nd February 2003, 08:53 PM

Jay

I did try him (Kirchoff, that is), but he was not very approachable ...

Nic

Jay · 22nd February 2003, 10:18 PM

I made my quick "calculation" based on simple logic. The circuit has a physical layout that almost "symetrical": 1/4W resistor - Vds - Vds - 1/4W resistor.

Whatever the DC rail, the input should have only a few mV above ground, right? With Vgs around 3 to 4V, the Drain of current source should at most 5V above ground. Then how do you share a 25V between Vds and a 1/4W resistor? (assumming a 30V rail)

I'm not good at electronics, so would you look at it for me once more, please?

JoeD · 23rd February 2003, 03:48 AM

These Mosfets Do Not need a heat sink.
I have a genuine Aleph 5; it does not have heat sinks on these mosfets. The mosfets stand off the board vertically.
I have built two mono Aleph 2 clones with no heat sinks on these mosfets.
All are working.

Good Luck

Jay · 23rd February 2003, 03:45 PM

Agree with JoeD. You don't need a heatsink.

In my case, I use a 40V-0-40V transformer. Originally, I didn't use any heatsink, and I used a resistor to offset the DC in the current source. Later, I removed the resistor and put a heatsink on the ccs MOSFET.

What is the specified rail for Aleph2? 30V? 35V? If 35V, I believe there is a considerable amount of heat. You can do the math if you think it is worth to do

Jay · 23rd February 2003, 03:51 PM

Oh, may be I can find IRF9610 with the highest Vgs for the ccs. Does this make sense?

blank527 · 6th May 2003, 03:18 AM

Hi,

Regarding in this old thread, I have a question.
After powering up my aleph 60, it starts just right up.
The sound is audible, but after a few minutes, one of the diff pair become very hot, Q2. Q1 doesn't get even hot, but they are matched pairs.. Q3 also gets hot, but thats logical.
When powering it down with the variac, the sound is very long audible, but there is 140.000mF p/ch.
By the way, I left out the resistor R0 out, wich is 3@3W.
Is this the reason for the heat differential?
I'm not using heatsinks for these pairs.

Thank you,
Remco

mpopovics · 6th May 2003, 07:43 AM

Are you drive it in single ended mode or balanced mode?
If you drive it in single ended mode, you should take a jumper in balanced input negative side to ground (as it is written in manual).
Small heatsink is preferred for Q1-Q3, R0 recommended (in my opinion).

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Aleph P1.7 heat sink?	sugano	Pass Labs	1	11th July 2006 02:56 PM
Aleph X heat sink thread	Peter Daniel	Pass Labs	306	24th July 2003 12:17 PM
Aleph 2 Heat Sink (chassis)	TjongKristian	Pass Labs	32	21st December 2002 05:19 PM
Aleph 3 Heat sink capability	raincheck	Pass Labs	27	25th June 2002 03:14 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

22nd February 2003, 08:53 PM	#21
Nicwix diyAudio Member Join Date: Dec 2001 Location: Sydney, Australia	Jay I did try him (Kirchoff, that is), but he was not very approachable ... Nic

22nd February 2003, 10:18 PM	#22
Jay diyAudio Member Join Date: Feb 2003 Location: Jakarta	I made my quick "calculation" based on simple logic. The circuit has a physical layout that almost "symetrical": 1/4W resistor - Vds - Vds - 1/4W resistor. Whatever the DC rail, the input should have only a few mV above ground, right? With Vgs around 3 to 4V, the Drain of current source should at most 5V above ground. Then how do you share a 25V between Vds and a 1/4W resistor? (assumming a 30V rail) I'm not good at electronics, so would you look at it for me once more, please?

23rd February 2003, 03:48 AM	#23
JoeD diyAudio Member Join Date: Feb 2002 Location: Mount Vernon, New York	These Mosfets Do Not need a heat sink. I have a genuine Aleph 5; it does not have heat sinks on these mosfets. The mosfets stand off the board vertically. I have built two mono Aleph 2 clones with no heat sinks on these mosfets. All are working. Good Luck

23rd February 2003, 03:45 PM	#24
Jay diyAudio Member Join Date: Feb 2003 Location: Jakarta	Agree with JoeD. You don't need a heatsink. In my case, I use a 40V-0-40V transformer. Originally, I didn't use any heatsink, and I used a resistor to offset the DC in the current source. Later, I removed the resistor and put a heatsink on the ccs MOSFET. What is the specified rail for Aleph2? 30V? 35V? If 35V, I believe there is a considerable amount of heat. You can do the math if you think it is worth to do

23rd February 2003, 03:51 PM	#25
Jay diyAudio Member Join Date: Feb 2003 Location: Jakarta	Oh, may be I can find IRF9610 with the highest Vgs for the ccs. Does this make sense?

6th May 2003, 03:18 AM	#26
blank527 diyAudio Member Join Date: Nov 2001 Location: Haarlem	Hi, Regarding in this old thread, I have a question. After powering up my aleph 60, it starts just right up. The sound is audible, but after a few minutes, one of the diff pair become very hot, Q2. Q1 doesn't get even hot, but they are matched pairs.. Q3 also gets hot, but thats logical. When powering it down with the variac, the sound is very long audible, but there is 140.000mF p/ch. By the way, I left out the resistor R0 out, wich is 3@3W. Is this the reason for the heat differential? I'm not using heatsinks for these pairs. Thank you, Remco

6th May 2003, 07:43 AM	#27
mpopovics diyAudio Member Join Date: Apr 2002 Location: Hungary	Are you drive it in single ended mode or balanced mode? If you drive it in single ended mode, you should take a jumper in balanced input negative side to ground (as it is written in manual). Small heatsink is preferred for Q1-Q3, R0 recommended (in my opinion).

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)