The simplistic Salas low voltage shunt regulator

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#744
Hi,

I'm very interested in using this shunt to power the digital section of my Buffalo32s dac.

Has anyone used this circuit (thinking V1 at the moment) at this voltage?

Something that is not coming across clearly to me in this thread (and it's probably me being thick) is how to set this board up for different voltages/current demand requirements, and also how much headroom to allow for to be dropped across the regulator?

The Buffalo requires 5V, 125mA.

Any info for the above, and component choice, would be appreciated.
 
#745
Try this one. I don't like to go so low in Voltage output, near the Mosfet Vgs margins, but this one looks like working alright on the simulator. Try it, I haven't tried for 5V before. Its inexpensive to make p2p and see if it will do well for you.
 

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#747
Salas said:
Try this one. I don't like to go so low in Voltage output, near the Mosfet Vgs margins, but this one looks like working alright on the simulator. Try it, I haven't tried for 5V before. Its inexpensive to make p2p and see if it will do well for you.
Click to expand...

I remember back in this post

http://www.diyaudio.com/forums/showthread.php?postid=1824458#post1824458

you said that IRF9540 could be used for this purpose. Is that still the case? I have a bundle of them waiting to be used for something.

btw, i've already built a couple of V1's at 15V and they are working great 🙂
 
#752
Hi all,

My first post to this thread. I've hardwired a 5V shunt reg as show in Salas reply to Woodenhead to try it on my Buffalo32S as well. I used 2-LM336Z-2.5V in place of D1 (just happen to have plenty of them around). The output is sitting at 5.6V which should be good for the dac. I used 3 green LED for the CCS ref and I found the voltage drop across R1(10 Ohm) is 1.7V. This translates to 170mA of Iccs. However the DAC is said to draw 125mA. Should I lower the R1 for more Iccs?

I am a shunt reg advocate. I've been using Borbely's super shunt and Allen Wright's HV shunt reg in my ss and tube pre respectively. This reg will replace the Jung/Didden super reg for digital supply in my B32s dac.

My sincere appreciation to Salas and all contributors to this reg here!
Prakit
 

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#756
prakit said:
Hi all,

My first post to this thread. I've hardwired a 5V shunt reg as show in Salas reply to Woodenhead to try it on my Buffalo32S as well. I used 2-LM336Z-2.5V in place of D1 (just happen to have plenty of them around). The output is sitting at 5.6V which should be good for the dac. I used 3 green LED for the CCS ref and I found the voltage drop across R1(10 Ohm) is 1.7V. This translates to 170mA of Iccs. However the DAC is said to draw 125mA. Should I lower the R1 for more Iccs?

I am a shunt reg advocate. I've been using Borbely's super shunt and Allen Wright's HV shunt reg in my ss and tube pre respectively. This reg will replace the Jung/Didden super reg for digital supply in my B32s dac.

My sincere appreciation to Salas and all contributors to this reg here!
Prakit
Click to expand...

Hey Prakit, thanks for testing the circuit out for me! Do you think that 5.6V might be a little high for the Buffalo? How would the value be brought down a little?

Subjective thoughts on the differences between this and your previous regulator would be very interesting, as Salas says.
 
#757
5V Salas's Shunt Reg in B32S

I installed the reg in the dac last night and left it on for burn-in. This morning I checked it and everything was in order before gave it a listen.

To answer Woodenhead about the Vreg=5.6V, yes, it's slightly high but I think it's absolutely fine. If you use the 4,7V Zener for D1, it should be closer to optimal 5V.

This listening impression is relative to the Jung/Didden reg.
Good news first. Overall the dac sounds more liquid. The mid is slightly sweeter and more fleshed out. However, the good news stops here. It sounds very dull in the hi. The bass(in which I feel is the strength of B32S) is also a bit thin and not very tight. Sorry but I have to say it doesn't sound right.

I have a feeling that some parts are not working at their optimal point. 5V is quite low. Beside the D1 that I substitute with 2xLM336-2.5, I wonder if the choice for Q3 is critical? I can't find a BC550C so I liberally use a 2SC1627A here. All JFet were chosen according to specified Idss.

Best
Prakit
 
#759
Its possible is not good at 5V or not good for the B32S. I did not feel that at 5V there is a lot of room for the elements. But LM336s maybe not optimal with the current we use for their ccs here. Try a 4V3 or 4V7 Zener and listen again. Also try to use a driving transistor with hfe about 300. If it remains dull (or you just like a sharper sound), it is always scalable for higher voltage and try out in another circuit you may have in the future. Also Tham will let us know what happens with his own DAC.
 
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