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Old 4th October 2009, 05:05 AM   #1191
iko is offline iko  Canada
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Sorry to hear about your headache.

The zener can be a 1N4744A. I would not remove that cap. V1 has been extensively tested and tweaked by people with good ears, and the consensus is that the cap is needed. My noise measurements confirm this. But best is to make your own mind.

About the choice of caps, salas and nicoch46 can say much more. The thread in which salas has first made the regulator available is this
Simplistic NJFET RIAA

There are many comments there about tweaks, but it's also a long thread.

About heat sinks. The inherent workings of the shunt are such that the more current the load draws, the less current will go through the shunt mosfet (the mosfet that passes current to ground). The CCS mosfet, the one after R1, passes a steady total current all the time. The IRFP9240 and IRFP240 are TO-247 devices, they can dissipate quite a lot of heat if properly heat sink-ed.

Have a look at these two.

Click the image to open in full size.

Click the image to open in full size.

Edit: this is V1

Last edited by iko; 4th October 2009 at 05:23 AM. Reason: Made clear this is V1
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Old 4th October 2009, 05:09 AM   #1192
ncc is offline ncc
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Hi Salas, Ikoflexer and everyone,

I need a schematic of Salas V1 for my DAC which require +15V at 68ma and -15V at 43ma.
I have a two dual 15V transformer already.
I would be gratefull if you have any equivalent schematics for me.
I have a question for the voltage reference, for example because I need 15V output if I place a 9V zener in serie with three 1.8V led would this be OK?

Thank you
ncc
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Old 4th October 2009, 05:22 AM   #1193
iko is offline iko  Canada
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Yes, LEDs in series with the zener shouldn't be a problem. For schematic, see my post before yours (post 1191). That is V1.
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Old 4th October 2009, 09:37 AM   #1194
Salas is offline Salas  Greece
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Quote:
Originally Posted by ncc View Post
Hi Salas, Ikoflexer and everyone,

I need a schematic of Salas V1 for my DAC which require +15V at 68ma and -15V at 43ma.
I have a two dual 15V transformer already.
I would be gratefull if you have any equivalent schematics for me.
I have a question for the voltage reference, for example because I need 15V output if I place a 9V zener in serie with three 1.8V led would this be OK?

Thank you
ncc
Don't use a 9V zener, its one of the bad noise zener region. Use 7 - 8 red leds instead. Match them and see how near 15V they get you. Polarity of leds is the same as the 3 leds go in above schematics in each positive and negative shunt. R1=15R 2W is enough current for your application, +/- 150mA CCS. 6R8 runs it above 200mA with most leds. Not necessary.
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Old 4th October 2009, 01:23 PM   #1195
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Thank Salas and Ikoflexer !!!
to day I finish the Salas shunt for my DAC!
I think It is very good, and wonderfull, I draw again cricuit, anh I make some
board!
I use tow LEDS and Trim change to zener! That is better!
thank you again!
QuangHao
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File Type: jpg Sala-shunt-for-DAC.jpg (497.8 KB, 1168 views)
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Old 4th October 2009, 02:58 PM   #1196
iko is offline iko  Canada
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I forgot to mention, everyone. For the easy entry to V1, have a look at this:
http://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer-post1941578.html

There's a group buy for a nice board which includes dual rail regulator, direct coupled B1 buffer, and soft start. But some people get the boards only for the regulator (easy to change voltage out, current, etc.).

Disclaimer: I have nothing to do with the GB, just mentioned it in case it may be helpful.

GB

http://www.diyaudio.com/forums/showt...00#post1941600

salas, you weren't around earlier so I took the liberty to post a dual rail schematic of V1. Let me know if I should change anything.
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Old 4th October 2009, 03:02 PM   #1197
Salas is offline Salas  Greece
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Quote:
Originally Posted by quanghao View Post
Thank Salas and Ikoflexer !!!
to day I finish the Salas shunt for my DAC!
I think It is very good, and wonderfull, I draw again cricuit, anh I make some
board!
I use tow LEDS and Trim change to zener! That is better!
thank you again!
QuangHao
Great draw quality schematic. Thanks. Seems I got a new nickname in the Far East.

All the guys who want a DAC 5V version may refer to this. Endorsed for visual clarity and optimum Vref. The 100R in series with two leds is a trimmer.
The resistor in the CCS IRFP9240 is the 470R.
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Old 4th October 2009, 03:02 PM   #1198
iko is offline iko  Canada
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I forgot to mention, everyone. For the easy entry to V1, have a look at this:
http://www.diyaudio.com/forums/showthread.php?p=1941578

There's a group buy for a nice board which includes dual rail regulator, direct coupled B1 buffer, and soft start. But some people get the boards only for the regulator (easy to change voltage out, current, etc.).

Disclaimer: I have nothing to do with the GB, just mentioned it in case it may be helpful.

GB

http://www.diyaudio.com/forums/showt...00#post1941600

salas, you weren't around earlier so I took the liberty to post a dual rail schematic of V1. Let me know if I should change anything.
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Old 4th October 2009, 03:08 PM   #1199
Salas is offline Salas  Greece
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I have seen it before I went voting. Its OK.

I may remind that the DCB1S shunt's part is tuned to it, and I would prefer jameshill pcb liberty. I run the positive Vref harder on that GB's shunt part for special reasons.

Thanks Iko for keeping the thread informative.
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Old 4th October 2009, 03:20 PM   #1200
iko is offline iko  Canada
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Cool. Yes, James did a very nice job on the layout. Here's the link to his work:

http://www.diyaudio.com/forums/showp...&postcount=226

At some point it'd be nice to start a wiki with all the different layouts, etc.

Voting eh? It seems your taxes will go up the left is winning?
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