Aleph 2 Differences in power consumption

Thago · 22nd January 2008, 02:19 PM

So, finally, after > 6 months, I finalised my 2nd Aleph 2 monobloc (will post some pictures later).
I fired them up last Sunday, and they sound so great!! (I'm not so good in hifi-magazine like superlatives, but I agree on everything that has been written on this forum about the sound of Aleph's)

But... after they were playing some time I noticed that one of the monoblocs gets hotter than the other one. The largest difference is measured at the current source transistors: warm heatsink (you can leave your hand on for a long while) for one monobloc vs. hot heatsink (you would want to retrieve your hand after a couple of seconds, but not so hot that you would burn your hand) for the other one. I also noticed that the hottest monobloc draws appr. 1.7A from the power line, while the cooler one draws appr. 1.5A (both at appr. 230V).
I cannot really say that I hear a difference between both channels. I am now wondering what could cause this difference. And if something is wrong, should I than suspect the hot or the cool one? And where should I search the problem, if any?
Thx in advance for answering!

Nelson Pass · 22nd January 2008, 03:01 PM

I suggest that you measure the DC drop across the Source
resistors of each output device. They should be be consistent.

Thago · 22nd January 2008, 08:44 PM

Hello Mr. Pass

It is incredibly encouraging for me to be advised personally by you!
I did as you told me, and measured the dc voltage across the source resistors.
I fist measured the gain devices, and voltages were all in the 0.37-0.38V range.
Then I measured the constant current devices, they showed voltages in the range of 0.45-0.46V, except the fift device: 0V!!
I removed the PCB from the heat sink, and guess what: I found one bad solder joint! I've repaired it, and now voltages over the source resistors of the gain devices are in the 0.47-0.48V range. Problem solved!

Thank you for sharing your IP rights with the DIY community!

Greetings from Belgium

Netlist · 22nd January 2008, 08:50 PM

Care to share a few pictures, if any?

/Hugo

Nelson Pass · 22nd January 2008, 09:17 PM

Quote:

Originally posted by Thago
Then I measured the constant current devices, they showed voltages in the range of 0.45-0.46V, except the fift device: 0V!!
I removed the PCB from the heat sink, and guess what: I found one bad solder joint! I've repaired it, and now voltages over the source resistors of the gain devices are in the 0.47-0.48V range.

We always measure the current through each Mosfet.

22nd January 2008, 02:19 PM	#1
Thago diyAudio Member Join Date: Nov 2006 Location: Asse, Belgium	Aleph 2 Differences in power consumption So, finally, after > 6 months, I finalised my 2nd Aleph 2 monobloc (will post some pictures later). I fired them up last Sunday, and they sound so great!! (I'm not so good in hifi-magazine like superlatives, but I agree on everything that has been written on this forum about the sound of Aleph's) But... after they were playing some time I noticed that one of the monoblocs gets hotter than the other one. The largest difference is measured at the current source transistors: warm heatsink (you can leave your hand on for a long while) for one monobloc vs. hot heatsink (you would want to retrieve your hand after a couple of seconds, but not so hot that you would burn your hand) for the other one. I also noticed that the hottest monobloc draws appr. 1.7A from the power line, while the cooler one draws appr. 1.5A (both at appr. 230V). I cannot really say that I hear a difference between both channels. I am now wondering what could cause this difference. And if something is wrong, should I than suspect the hot or the cool one? And where should I search the problem, if any? Thx in advance for answering!

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
Power consumption v. rms output	kyrie48	Solid State	7	1st November 2008 04:41 PM
power consumption	tfrei	Chip Amps	2	1st December 2007 10:34 PM
PCB and schematic differences on Aleph 5.	Tony D.	Pass Labs	4	3rd May 2002 08:39 PM
( stupid ? ) idea to reduce power consumption	Bernhard	Pass Labs	18	28th April 2002 12:02 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 January 2008, 03:01 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	I suggest that you measure the DC drop across the Source resistors of each output device. They should be be consistent.

22nd January 2008, 08:44 PM	#3
Thago diyAudio Member Join Date: Nov 2006 Location: Asse, Belgium	Hello Mr. Pass It is incredibly encouraging for me to be advised personally by you! I did as you told me, and measured the dc voltage across the source resistors. I fist measured the gain devices, and voltages were all in the 0.37-0.38V range. Then I measured the constant current devices, they showed voltages in the range of 0.45-0.46V, except the fift device: 0V!! I removed the PCB from the heat sink, and guess what: I found one bad solder joint! I've repaired it, and now voltages over the source resistors of the gain devices are in the 0.47-0.48V range. Problem solved! Thank you for sharing your IP rights with the DIY community! Greetings from Belgium

22nd January 2008, 08:50 PM	#4
Netlist diyAudio Moderator Join Date: Jan 2003	Care to share a few pictures, if any? /Hugo

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