Simplistic MosFET HV Shunt Regs

[merlin el mago]

I used 6VAC tx for the AZ1 heaters and between the 6VAC hot to AZ1 1R in series to lowered to 4VAC, I measured to check and I have 4,9VAC instead 4VAC, I changed to 2R and now I have 4VAC at the AZ1 heaters the issue is fixed.

 

[Salas]

You know something weird, I had it in mind to ask what is going on with heaters next. Good. I wanna see picture of 80 yrs old AZ1 mesh plate glow over SSHV2.

 

[Salas]

Hi,

What is the right resistor value in order to set ccs of my salas HV shunt reg for a current value of about 30 mA ?
I would supply two #26 at 5,5 mA max each. I have two 30 ma choke on HV line in a c-l-c-l-c configuration and would not saturate them . As I also have other two spare similar 30 ma choke, can I put them in parallel in order to increase max current value?

Thanks for your helps!

Anto

If its the one with single mosfet and 3 leds CCS start with 68R. That one is SSHV(1). SSHV2 has a trimmer, 2 mosfets, a test point, and no leds in ccs.

Yep, parallel the chokes. But maybe you don't wanna spare all your valuable chokes since the reg is gonna cut much ripple too. Maybe just c-l-c one cell is enough.

 

[10y]

If its the one with single mosfet and 3 leds CCS start with 68R. That one is SSHV(1). SSHV2 has a trimmer, 2 mosfets, a test point, and no leds in ccs.

Yep, parallel the chokes. But maybe you don't wanna spare all your valuable chokes since the reg is gonna cut much ripple too. Maybe just c-l-c one cell is enough.

Thank you Salas, I was talking about SSHV (1). So will start with a c-l-c configuration with two parallelled choke for a 60 mA current max and 68 R ccs value. Is also possible to reduce current ccs consumption to a value below 20 mA? Thinkin' about tu use two SSHV1 in a single HV rail and stand below 30 mA max.

I wanna see picture of 80 yrs old AZ1 mesh plate glow over SSHV2.

You will see the mine soon

Anto

 

[merlin el mago]

You know something weird, I had it in mind to ask what is going on with heaters next. Good. I wanna see picture of 80 yrs old AZ1 mesh plate glow over SSHV2.

Yes Sir

 

[10y]

If its the one with single mosfet and 3 leds CCS start with 68R. That one is SSHV(1). SSHV2 has a trimmer, 2 mosfets, a test point, and no leds in ccs.

Yep, parallel the chokes. But maybe you don't wanna spare all your valuable chokes since the reg is gonna cut much ripple too. Maybe just c-l-c one cell is enough.

Thank you Salas, I was talking about SSHV (1). So will start with a c-l-c configuration with two parallelled choke for a 60 mA current max and 68 R ccs value. Is also possible to reduce current ccs consumption to a value below 20 mA? Thinkin' about tu use two SSHV1 in a single HV rail and stand below 30 mA max.

I wanna see picture of 80 yrs old AZ1 mesh plate glow over SSHV2.

You will see the mine soon

Anto

 

[merlin el mago]

Mine is Siemens, what's your AZ1?

 

[10y]

sorry for the double post

 

[10y]

Mine is Siemens, what's your AZ1?

Hi Merlin,

see the pic.

I have another valvo 1938 az1 mesh plate.

Ciao

 

[merlin el mago]

Ciao,

Looks really good, Valvo are considered by many the best AZ1 mesh plate ever made so please pic of Valvo.

Cheers
Felipe

 

[Salas]

Mesh 30's is the duck's guts. Not bad yours Merlin also. Nice pics guys.

 

[Salas]

Thank you Salas, I was talking about SSHV (1). So will start with a c-l-c configuration with two parallelled choke for a 60 mA current max and 68 R ccs value. Is also possible to reduce current ccs consumption to a value below 20 mA? Thinkin' about tu use two SSHV1 in a single HV rail and stand below 30 mA max.



You will see the mine soon

Anto

Don't use less than 20mA for the reg itself, ups the Z, but yeah, if its like your choke is on edge for handling the total if you add for load too, what the heck, somewhat more Zo. Verify what you run there by VdropRset/RsetValue. Just because every led and fet ain't the same.

 

[10y]

Ciao,

Looks really good, Valvo are considered by many the best AZ1 mesh plate ever made so please pic of Valvo.

Cheers
Felipe

Done!

Not as good as the first but the red filament is magic!

ciao,

Anto

 

[merlin el mago]

Ciao Anto,

Phisicallly speaken seems more similar the Valvo to the Siemens than the Miniwat.

Grazie e ciao

Felipe

 

[10y]

Felipe,

in the same 220 V sec tx- graez- c-l-c- line the valvo shows 304 volt and the minivatt 280 volt " a vide"

Anto

 

[Salas]

We avoid too big pictures for everybody to see easily. I cut them to 1200.

 

[10y]

Don't use less than 20mA for the reg itself, ups the Z, but yeah, if its like your choke is on edge for handling the total if you add for load too, what the heck, somewhat more Zo. Verify what you run there by VdropRset/RsetValue. Just because every led and fet ain't the same.

Thanks Salas for your suggestions.

We avoid too big pictures for everybody to see easily. I cut them to 1200.

Ok Salas will do for the next

Anto

 

[disco]

enjoying the low capacitance benefits of a mesh plate here?
BTW that one pictured is a perforated plate, mesh is built from loose wires.


Salas,

I felt the urge to update my three year old PCBs for SSHVSR-version1 with kelvin connections. The plan is to run 30cm (twisted +/-) wires to the load. Now I hesitated to put the zobel at the load or across Q3. Any changes when employing IRFP9140 instead?

An externally hosted image should be here but it was not working when we last tested it.

 

[Salas]

Across Q3 is its best place, and star gnd at its capacitor. No changes for IRFP140, and you can use IRF9620 for cheaper TO-220.

 

[disco]

Another idea

When splitting the power part from the drive part, the driver would be exposed to less heat. Can the connection to R7 be streched to 30cm?

An externally hosted image should be here but it was not working when we last tested it.

Alright, not - as it would destroy the kelvin connection effect.