The simplistic Salas low voltage shunt regulator - Page 569 - diyAudio
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Old 4th February 2013, 03:45 AM   #5681
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Quote:
Originally Posted by AndrewT View Post

if you need a Vref between 1.3V and 2.2V.

Two LEDs in series can work out better.

mmmmmmmmmmmmm usually the Vd for a [visible light] LED ranges from 1.6v [if I recall properly] or so to 3V or more................depends on color and type of LED
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Old 4th February 2013, 03:51 AM   #5682
Salas is offline Salas  Greece
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Most generic reds give me 1.8 to 1.92V these days, greens 2.1 to 2.2V, have older red and yellow ones in the 1.65-1.75V. Talking 2.5-5mA bias.
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Old 4th February 2013, 03:55 AM   #5683
Salas is offline Salas  Greece
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Originally Posted by ikoflexer View Post
Measuring with the scope probe this way will always add some noise, in my experience. For critical measurements I always take the probe sheath off and use a very short solid copper wire from the scope probe to the load ground. Makes a big difference for sub-millivolt measurements. Hehe, your work brings back good memories.
Indeed. Those springy short path to earth bits come free in the bags of even $20 ebay "100MHz" at x10 probes and we better always save them somewhere, they come handy.
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Old 4th February 2013, 10:41 PM   #5684
johnm is offline johnm  United Kingdom
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Originally Posted by johnm View Post

Click the image to open in full size.

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After using the above shunt PCB with a DAC for quite some time for 5v output into a DAC, I have decided to re-use this shunt PSU for my Creek OBH-15 phono stage (24v 30mA required) as I no longer use that particular DAC.

A 5K trimmer, and 15R 5W current setting resistor will be substituted onto the shunt PCB, to enable setting 24v.

Whilst the Creek isn't the Highest of Fi, it's still pretty good, and will do until I finally get together all the parts for a Salas RIAA stage.

Until then, I'm seeing what effect using the above shunt reg will have on the Creek phono stage.

Just one question, I seem to remember reading somewhere in this thread (and I cannot find it after a search!) that for a transformer roughly AC volts in = DC volts out. So if I require to use this shunt for 24V output I assume I need to purchase a 2x12v transformer and wire it for 0-24v?

Have I got that right?

Many thanks

- John


P.S. Will I need heavier duty heatsinking than shown in the above picture to run this shunt reg PCB at 24v instead of the original 5V? Ta.

Last edited by johnm; 4th February 2013 at 10:43 PM.
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Old 4th February 2013, 10:53 PM   #5685
Salas is offline Salas  Greece
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Yes to both questions.
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Old 4th February 2013, 11:01 PM   #5686
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Quote:
Originally Posted by Salas View Post
Most generic reds give me 1.8 to 1.92V these days, greens 2.1 to 2.2V, have older red and yellow ones in the 1.65-1.75V. Talking 2.5-5mA bias.

thx. if I might add that the ultra-bright white LEDs can exceed 3V
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Old 4th February 2013, 11:01 PM   #5687
johnm is offline johnm  United Kingdom
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Originally Posted by Salas View Post
Yes to both questions.
Thanks Salas

John
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Old 4th February 2013, 11:06 PM   #5688
canvas is offline canvas  Taiwan
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Originally Posted by KMossman View Post
thx. if I might add that the ultra-bright white LEDs can exceed 3V
If I remember correctly, there is noise consideration. White (blue) LEDs are noisier than red, green ones.
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Old 4th February 2013, 11:07 PM   #5689
Salas is offline Salas  Greece
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Originally Posted by KMossman View Post
thx. if I might add that the ultra-bright white LEDs can exceed 3V
But not that usable in our referencing purposes here because noisy enough. Sure low noise and lowest Vf are IR LEDS.
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Old 6th February 2013, 11:57 AM   #5690
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by johnm View Post
After using the above shunt PCB with a DAC for quite some time for 5v output into a DAC, I have decided to re-use this shunt PSU for my Creek OBH-15 phono stage (24v 30mA required) as I no longer use that particular DAC.

A 5K trimmer, and 15R 5W current setting resistor will be substituted onto the shunt PCB, to enable setting 24v.

Whilst the Creek isn't the Highest of Fi, it's still pretty good, and will do until I finally get together all the parts for a Salas RIAA stage.

Until then, I'm seeing what effect using the above shunt reg will have on the Creek phono stage.

Just one question, I seem to remember reading somewhere in this thread (and I cannot find it after a search!) that for a transformer roughly AC volts in = DC volts out. So if I require to use this shunt for 24V output I assume I need to purchase a 2x12v transformer and wire it for 0-24v?

Have I got that right?

Many thanks

- John


P.S. Will I need heavier duty heatsinking than shown in the above picture to run this shunt reg PCB at 24v instead of the original 5V? Ta.
Hi John

Is this a BiB clone ?
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