Simple Super Shunt and Simple Super Shunt w/CCS vs. JSR03/05 (and other series regs)

[joho]

Originally posted by Onvinyl
Hi,

It is however not so easy to use low noise references since they are normally low voltage. I use bypassed resistor stabliized with a FET CCS, but it is not easy to fix the voltage.
Any idea to circumvent this is welcome, and, at least for high gain circuits, pretty much a must.
I don't see how the proposed local regulator could work. Does it depent on leakage current?
Rüdiger

Hi Rüdiger,

The supply i suggested is used for a low gain line amp so a "noisy" zener doesn't matter. Regs for a mc-pre is a different story.

I was also thinking about that low voltage,low noise references but for an open loop regulator it's a bit difficult. Is it posible to put them in series as a normal zener? Say four 5V references for a 20V reg. I never tried this but i suppose the noise is also four times larger but still low. Also the price is relative high.

The local regulator works very fine, try it. John Curl used something like that in his Vendetta amps. His variation is a 220uF bipolar at the gate and a lower resistor(10k or so). I also will try that configuration. But time ...
Somewere in the beginning of the blowtorch thead is a lot of background information about this issue.

Gr.
Johan

[housing]

Does anybody try Borbely's all FET low noise super-shunt regulator? Is it really that good?

[peranders]

Mr. Borberly has never released anything doubtful. I'll guess the design is pretty good.

[hermanv]

Originally posted by joho
Hello again,

Attached the schematic of the regulator i'm testing/listening to.
You must try different zener/diode combinations to get the output voltage you need. Please also test it with the current you need because there is no feedback and the voltage get's a bit lower when the current raise.
The most fet folower is a la Charles Hansen's Ayre V3 if i'm right.
Personally i like Mundorf Suprime cap's but they are not cheap and small. The northcreek cap's are new for me. The price is better than the Mundorfs. For sure when the dollar is low and the euro high. But shipping cost...
I do not prefer any particular brand/type of Zener. When i buy some in the shop at the corner it's always a supprise what you get.

Gr.
Johan

I haven't built or modeled this design, still I propose some modest schematic changes:
1. Swap values on C1 and C2, let the bulk storage do just that and let the regulator remove ripple.
2. Increase LED current, make R1 7.5K instead of 15K, this improves the "knee" and makes the output voltage less susceptible to input voltage variations or ripple.

If the output voltage is 28V, make sure the input voltage is at least 31V (32?) at the bottom of the ripple voltage when under full load. Otherwise the beta of the Darlington will drop too low resulting in poor regulation (noise?). The idea is to have at least 4V across the active regulator/capacitor multiplier Darlington.

Since there is a capacitor at almost every node, the design might oscillate under the right load conditions due to cumulative phase shift.

[joho]

Hi HermanV,

Thank you for the advices.

I use the regulators(pre+local reg) very close to the preamp module. It's like a sandwich. Between the raw dc, which is situated around the transformer, and the regulator is 1m cable. I measued a significent lower noise level at the input of the reg when i use that 100uF (low imp.) caps.
The reg is very stable for voltage variations at the input. 10 volts input "swing" results in a few mv output variation.
The design is more then 10 years old and i don't remember why i used 15k but it's easy to change that value and measure again.
I think the critical input voltage was around 31.5 volt so your're right. i use 35V input.
I have no oscillation problems but the 1N cap between base and collector of Q3/Q4 should reduce such things.
B.t.w. This reg looks very simple and old fashioned but sounds much better than the simple shunt reg in the beginning of this thread.
At this moment i will try some other variations of the last source follower but time...

Johan

[maxpou]

Hi Joho,
i would like to know what's the regulator has the better sound for you in this tread. Thank You! Maxpou

[joho]

Hi Maxpou,

Please look at the "UGS adventures" thread first.
http://www.diyaudio.com/forums/showt...04#post1416904

The schematic i post in this thread with the BD139/140+source follower and mundorf cap is the one i like best.
It sounds more open than the shunt regulaters i tested. With the shunt regs was more limitation.
http://www.diyaudio.com/forums/showt...54#post1422454

Johan

[maxpou]

Thank You Joho,
i have this PS for my preamp, do you have tried a same regulator? Maxpou

[pietjers]

Johan,

Have you compared the sonic results with/without the local regulation? If so, what are the sonic benefits of this local regulation? And, if you were able to have the circuitry of the pre regulator very close to the load, would the local regulator be of any use?

Peter

[sandyK]

A very effective Super Shunt from the late John Linsley Hood, as published originally in E.T.I. This regulator can be configured to work in either polarity, and with suitable component changes has been adapted by "awpagan" from DiyAudio to work with + and - 55V rails in the front end of amplifiers,as wellas currents of >500mA.