• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

Statistical regulator from VA 4rd edition

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#41
I'm well aware of the WJ variant - it improves the ripple rejection from -150dB to -160dB at low frequencies, however both figures are very close to measurable limits and certainly not audible in this use case. The modified variant only has 3 extra components but one of these is another fairly large capacitor - I may go down this route later but my primary area of research currently is using an alternative for M1 as it isn't dissipating nearly so much energy and there are better option.

The real story here isn't about the CCS anyway - that's only being used to set the operating point of the zeners - it's all about regulator noise.
 
#43
Zekk said:
Hi Nick... Can you possibily sell me one completed and tested regulator?

I've screw-up all ten pcs. of my DN2540 and am wondering if they're actually fake or imitation stuff!? Why is it so fragile? Beleives there must be a rule of handling. How do you test it out before connecting to a high voltage supply?

Only success I've was using a single DN2540 to drive a pair of OD3.

What I really need is a regulated and stable 300vdc @ 50mA.

Thanks!
Click to expand...

Zekk,

just saw your post now. I fried some of mine DN2540 because the soldering iron's tip wasn't properly grounded, and the ESD killed the chips. Now, every time I deal with SS stuff, I do check if the tip is grounded

Best, Erik
 
#44
regarding the WJ variant, with the additional resistors + cap.

Will it also do higher currents in comparison to the standard cascode? I do think so, but want to confirm.

With the standard cascode, when setting higher currents, the VGS of the upper element (actually of both elements) will become smaller and smaller. As VGS of upper element = VDS of lower element, the lower element does lose all of its VDS. With the WJ trick, even with a closer to saturation upper element (lower VGS), one can still give the lower element some more VDS to work properly? ?

Many thanks,
Erik
 
#45
If I am not misguided in my thinking, this V ref idea should subsitute nicely into the circuit included in place of the LND150 CCS based reference.
 

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#46
Yes - the reference voltage there is set by the CCS controlling the current through R4.

Note that the MJSR voltage is only adjustable in deltas of the chosen zener voltage, i.e. a typical granularity of 5.6V (*), but there are ways round that for such a low-current voltage reference - the CCS in the 01a G2 is only set to about 500uA/0.5mA.

(*) with 21 x 5V6 zeners under typical operating conditions you should get about 120.5V of regulated output.

FWIW, initial feedback from knowledgeable beta testers I've been using on another forum (mentioned above) has been extremely positive...
 
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#48
Starting with 6v6 and will progress to 301a, 10y, 801a, and maybe 45. Gonna use Ale's hybrid mu load on all in an attempt at a fair comparison. This LED referemce should make sure that noise is kept at bay, at least in the load components.
 
#52
I will have to look up an example of the Kelvin connection. It is new to me.

I had laid out the board for LED's when I realized it was a mistake. I just assumed that an LED would be quieter than a zener based on previously shared information here on the forum.
 
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