Simplistic MosFET HV Shunt Regs

diyAudio Chief Moderator
Joined 2002
Paid Member
Pretty well then. The soft RC to test goes on the other end of the regs, at the load's physical rail. Since with your better probe there seems to be very little to see on the scope if any, lets see if it can change something sonically or not. So what you reported above is after the new RC?
 
Member
Joined 2011
Paid Member
Hi

For my burfday I wish me a split SSHV2.5 for smaller preamp stuff. One CSS module eating the 20 mA extra current and 2 output/Vref sections, one for each channel.

Purpouse would be optimum channel separation without having to burn an extra 20 mA per channel for applications that might only take 10 for them selves. That would make need for smaller trafos, lesser EMC etc.

Do you think it would be fruitful for me to experiment? Is it possible to split to 2 mosfet/Vref sections after CSS?

best
Staffan
 
diyAudio Chief Moderator
Joined 2002
Paid Member
Hi

For my burfday I wish me a split SSHV2.5 for smaller preamp stuff. One CSS module eating the 20 mA extra current and 2 output/Vref sections, one for each channel.

Purpouse would be optimum channel separation without having to burn an extra 20 mA per channel for applications that might only take 10 for them selves. That would make need for smaller trafos, lesser EMC etc.

Do you think it would be fruitful for me to experiment? Is it possible to split to 2 mosfet/Vref sections after CSS?

best
Staffan

The extra 20mA is not for the CCS's benefit but for the shunt part(s). So you can't sidestep it by Y feeding. You will still need 20mA extra for each output.
 
Member
Joined 2011
Paid Member
The extra 20mA is not for the CCS's benefit but for the shunt part(s). So you can't sidestep it by Y feeding. You will still need 20mA extra for each output.

Thanks Salas. I realise this now. My slow thinking brain worries about channel separation with 1 SSHV for both channels but I should let it go because of the sturdy regulation cancels it I guess. Im thinking linear PSU.

Staffan
 
Hi Salas,
1. It looks to me like the CCS part of the SSHV (Simplistic Mosfet HV Shunt regulator) regulator (or any shunt regulator) is needed mainly to provide good line regulation. Is that correct?
2. Suppose I'll feed the SSHV with a regulated HV, (from a Maida-like regulator), can a resistor replace the CCS part without any degradation in the SSHV performance?

I ask it because I'm concerned about RFI creeping in to the amp circuit.
The PSU is going to be placed in a separate box (LCRC or LCRC + Maida-like). Whatever one may do in the PSU box, RFI will creep in, even by radiation, to the wires connecting the PSU box with the amp box. Therefore, I prefer having RC filtering in the amp box, both for the (+) and the (-) wires. It seems to me that resistors will have better HF and RF rejection than the DMOS CCS.

Another question:
3. Is there any potential problem with feeding the SSHV with gradually rising HV, either with or without the CCS section in the SSHV?
 
diyAudio Chief Moderator
Joined 2002
Paid Member
1. No, its for isolation.
2. No, different purposes.

Battling RFI is shielding and filtering to the 9th degree. In all boxes. If there is measured contamination in the first place.

3. No if its lowest point is at least 10 Volt higher than the set output and its top isn't high enough so to overheat the reg and/or challenge its max in spec even briefly.
 

iko

Ex-Moderator
Joined 2008
Think of the ccs as a very very large value resistor, but without the large voltage drop. The better the ccs in that position the better will the shunt portion work to give you in the same time low output impedance AND very good line noise rejection. This particular CCS gives you really good performance in the lower frequency range, and quite good going up in frequency.

A resistor instead of the ccs works technically but very bad at doing the tasks above.

Makes no sense to put a ccs on the ground/return wire.