Aleph 5 question

xenofex · 19th October 2002, 12:24 AM

Hi,

Power rating for Zener diode ? Is 1 watt enough.
Thanks in advance for your response

Best Regards
CB

GRollins · 19th October 2002, 12:40 AM

One watt is plenty. That's what Nelson uses, if I recall.
I used 1/2W. Still plenty of margin.

Grey

Peter Daniel · 19th October 2002, 01:00 AM

Although I didn't check it out, somebody on a forum reported that 1/2W zener for some reason sounded better.

blschuler · 19th October 2002, 01:37 AM

In my Aleph 4 rendering I tried 1watt zeners and then replaced them with 1/2watt one (just in the current source for the differential pair) and for what ever reason the sound of the amp improved.
I've also varied the amount of current throught the zeners and each time the change was noticeable. Instead of the original 3.9ma throught the zeners I'm running 5.6ma. Makes a heck of alot more difference then the blue LED in my transport!

For interests sake I'm using Digi-Key PN# 1N5239BDICT-ND. Perhaps the differences I'm hearing are the sort comings of this specific part?

Peter Daniel · 19th October 2002, 03:43 PM

And that's a very valuable information.

xenofex · 21st October 2002, 04:26 PM

I wish to thank you guys for your willingness to share your experience and knowledge I've another question about the zener diode, Actually I purchased them 1N4739A X 10 units / BZX85C9V1 X 40 units couple years back for Pass labs A75 DIY project.

Does this make sense? I recently try to match the zener diodes that's probably because nothing to do while waiting for the FETs.

Both zener diodes are 9.1V 1.0 W 5% but the actual measurement that I got is
1N4739A ------9.6xxx Vdc whereas BZX85C9V1------- 8.7xxx Vdc

Now I am unsure of which to go for? should I go for the higher or lower voltages one.

Thanks in advance for answering my silly question?

Best regads
cb

Peter Daniel · 21st October 2002, 04:34 PM

It is still very close to 5%, just the opposite ways. Do you only have to Zeners left? If it's gonna make you feel better, choose two with similar readings, otherwise you shouldn't worry.

The important thing is, you should be getting 4-5V volatage drop on drain resistor (392 ohm) in differencial pair. If it's off that value, then you should be concerned with zeners.

xenofex · 21st October 2002, 05:12 PM

Peter Daniel,
Hi and thanks for answering so fast. Actually I still have 1N4739A X 10 units & BZX85C9V1 X 40 units, coz I didn't finish Pass Labs A75 project.

Regards
cb

19th October 2002, 12:24 AM	#1
xenofex diyAudio Member Join Date: Aug 2002 Location: malaysia	Aleph 5 question Hi, Power rating for Zener diode ? Is 1 watt enough. Thanks in advance for your response Best Regards CB

19th October 2002, 01:00 AM	#3
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	Although I didn't check it out, somebody on a forum reported that 1/2W zener for some reason sounded better. __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

19th October 2002, 03:43 PM	#5
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	And that's a very valuable information. __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

21st October 2002, 04:34 PM	#7
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	It is still very close to 5%, just the opposite ways. Do you only have to Zeners left? If it's gonna make you feel better, choose two with similar readings, otherwise you shouldn't worry. The important thing is, you should be getting 4-5V volatage drop on drain resistor (392 ohm) in differencial pair. If it's off that value, then you should be concerned with zeners. __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

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19th October 2002, 12:40 AM	#2
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	One watt is plenty. That's what Nelson uses, if I recall. I used 1/2W. Still plenty of margin. Grey

19th October 2002, 01:37 AM	#4
blschuler diyAudio Member Join Date: Oct 2001 Location: Lethbridge, Alberta	In my Aleph 4 rendering I tried 1watt zeners and then replaced them with 1/2watt one (just in the current source for the differential pair) and for what ever reason the sound of the amp improved. I've also varied the amount of current throught the zeners and each time the change was noticeable. Instead of the original 3.9ma throught the zeners I'm running 5.6ma. Makes a heck of alot more difference then the blue LED in my transport! For interests sake I'm using Digi-Key PN# 1N5239BDICT-ND. Perhaps the differences I'm hearing are the sort comings of this specific part?

21st October 2002, 04:26 PM	#6
xenofex diyAudio Member Join Date: Aug 2002 Location: malaysia	I wish to thank you guys for your willingness to share your experience and knowledge I've another question about the zener diode, Actually I purchased them 1N4739A X 10 units / BZX85C9V1 X 40 units couple years back for Pass labs A75 DIY project. Does this make sense? I recently try to match the zener diodes that's probably because nothing to do while waiting for the FETs. Both zener diodes are 9.1V 1.0 W 5% but the actual measurement that I got is 1N4739A ------9.6xxx Vdc whereas BZX85C9V1------- 8.7xxx Vdc Now I am unsure of which to go for? should I go for the higher or lower voltages one. Thanks in advance for answering my silly question? Best regads cb

21st October 2002, 05:12 PM	#8
xenofex diyAudio Member Join Date: Aug 2002 Location: malaysia	Peter Daniel, Hi and thanks for answering so fast. Actually I still have 1N4739A X 10 units & BZX85C9V1 X 40 units, coz I didn't finish Pass Labs A75 project. Regards cb

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