Simplistic MosFET HV Shunt Regs

[regal]

High harmonic content, both odd and even, without signal even.

Ocsilation is the only explaination that makes sense.

Well with no signal, I don't see the high harmonic content. And with an easy load I don't even at 1V out, the tougher load I do but only as I increase the volume to give ~.5V across the 32ohm load on the secondary..


So with the lower load as I increase the grid ac input I am pushing the tube into oscillation or the SSHV into oscillation ?

 

[Salas]

I would be investigating a higher bias point for that load first.

 

[mogliaa]

Hi Salas,
Hope things are ok at your end. I'm in the process of building a 26 pre-amp. My current HT raw supply delivers about 305V at no load and sag down to 210V at 45mA roughly. The supply impedance is about 2K1. My current CLCLC filter smooths the ripple down to 12mV (rms) which is great.

My pre-amps needs 170V and consumes about 7mA per channel. based on your design, I set the shunt current to 40mA. From the simulation it seems that the circuit can regulate fine with the 40V difference. The HT may sag a bit more in practice, so may end up with a 30V difference or so. Will this be OK?

At the moment I used the IRFP9240 but I'm planning to use the FQP3P50 PMOS, but couldn't find the spice model for this....

Thanks for the help
Cheers,
Ale

 

[Salas]

Hi, fine here, trying to make ends meet, bootstrapping etc.

Use an IRF9610 for CCS duty, will have better PSRR in HF than FQP3P50 due to far less Ciss. 30V drop across the reg will be plenty to regulate well.

 

[mogliaa]

Hi Salas, thanks. Well, have the FQP3P50 at hand so will try them...
Will report results soon!
Thanks, Ale

 

[merlin el mago]

Any news about SSHV2?

Sure, I have shown schematic in the past. As in the other regs. SSHV2 will have as standard, if proven it mixes well. But I will have to go visit a friend that has #26 and horn speakers, and tweak there, compare SSHV installed already, gather opinion etc. Want to keep it comparably low parts count with gains in frequency etc. with no further stages, to can practically give better subjective impression also. A juggling act on trying to surely practically improve on a so widely liked and used circuit, not easy.

 

[Salas]

I finalized what I want to test but the test meeting with Vgeorge got postponed.

 

[massimo]

I finalized what I want to test but the test meeting with Vgeorge got postponed.

No ferry to Poros due to strikes?

P.S. Going to keep my promise

 

[Salas]

No, its just his car got bumped when just about to meet up.

 

[merlin el mago]

Remote sense

This schematic with remote sense is correct?

 

[merlin el mago]

bump

 

[Salas]

Looks OK.

 

[merlin el mago]

Thanks

 

[dadedady]

Hi Salas. I am thinking to make shunt reg. to power a stereo tube preamp. (2x 6N1P). The in V is about 330V the +B of pream. is 260V. Which of the to circuits in first page should I use? Have I to change the values of resistors?
Thanks in advance Dade

 

[Salas]

Wait a little, I will post a new better evolution really soon. In a few days.

 

[AndrewT]

By how much does the 330Vin vary as mains voltage varies.
I would expect at least +-5%, but you could be unlucky and have a range approaching +-10%.

We/you need to know this to determine the maximum component ratings and the heatsink maximum dissipation.

 

[dadedady]

Thanks both

 

[bigpandahk]

Hi Salas

I just built the HVSR and have checked all wiring twice. The 5.6K R5 start burning immediately when I apply 170V dc to the input. Can you advise what is the possible mistake I've made?

 

[Salas]

Something with the orientation or correct type of the MJE possibly?

 

[bigpandahk]

Thanks Salas for your prompt reply. I am using MJE350 and will check the orientation again.