Aleph3 voltage problem - Page 2

Nelson Pass · 19th November 2001, 09:34 PM

Certainly, but I wouldn't lose any sleep over it.

Forte · 20th November 2001, 02:10 PM

I build Aleph3 and found the Matching MOSFET is some kind of difficult. And few kinds of method for VGS measurements.
1. Use a power resistor to measurement it individual with same current & temp.
2. Use an Aleph3 circuit with only one Pair of IRFP240. Also individually.
3. Measurements it on real Aleph3 circuit. Check VGS on site.

Actually I do it step by step. Then, I can get closest VGS & Voltage over Source Resistor.

I got 16 of IRFP240 & Use 12 of them for my stereo Aleph3. I set 0.4V over 0.49ohm resistor (2W, 2%). All of the effort returns by Music. I am very enjoying it now. I think in such simple circuitry, have to control the performance by components quality & lots of matching works. Also more current is better.

rtirion · 20th November 2001, 08:24 PM

Kasra,

One channel running with 0.5V over each resistor and 0.6V in the other channel is fine by me.
Yes, I suspect this is partialy a consequence of using the BC550C in one channel and a ZTX450 in the other. Their is a noticable difference in gain for both transistors, so it is very likely to have an effect on the DC setting of the current source circuit. I don't think this is a negative effect. Actually a little more quiescent current in the ALEPH is probably a benefit. I know this small diffence will not have significant sonic effect.
So go ahead, and enjoy your ALEPH

Regards

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
PS Problem: How do I Reduce Voltage?	slor	Tubes / Valves	7	27th April 2008 03:18 PM
voltage problem in 400watt amp	jojo_tennis	Solid State	5	7th September 2005 03:33 AM
Voltage problem	sith	Tubes / Valves	10	7th January 2005 12:20 PM
BOSOZ, PS voltage problem or not?	PsykoK	Pass Labs	3	20th December 2002 08:12 AM
Aleph3 problem	rtirion	Pass Labs	30	1st April 2002 09:56 PM

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

19th November 2001, 09:34 PM	#11
Nelson Pass The one and only Join Date: Mar 2001	Certainly, but I wouldn't lose any sleep over it.

20th November 2001, 02:10 PM	#12
Forte diyAudio Member Join Date: Oct 2001 Location: Taipei TW	I build Aleph3 and found the Matching MOSFET is some kind of difficult. And few kinds of method for VGS measurements. 1. Use a power resistor to measurement it individual with same current & temp. 2. Use an Aleph3 circuit with only one Pair of IRFP240. Also individually. 3. Measurements it on real Aleph3 circuit. Check VGS on site. Actually I do it step by step. Then, I can get closest VGS & Voltage over Source Resistor. I got 16 of IRFP240 & Use 12 of them for my stereo Aleph3. I set 0.4V over 0.49ohm resistor (2W, 2%). All of the effort returns by Music. I am very enjoying it now. I think in such simple circuitry, have to control the performance by components quality & lots of matching works. Also more current is better.

20th November 2001, 08:24 PM	#13
rtirion diyAudio Member Join Date: Nov 2000	Kasra, One channel running with 0.5V over each resistor and 0.6V in the other channel is fine by me. Yes, I suspect this is partialy a consequence of using the BC550C in one channel and a ZTX450 in the other. Their is a noticable difference in gain for both transistors, so it is very likely to have an effect on the DC setting of the current source circuit. I don't think this is a negative effect. Actually a little more quiescent current in the ALEPH is probably a benefit. I know this small diffence will not have significant sonic effect. So go ahead, and enjoy your ALEPH Regards