Simplistic MosFET HV Shunt Regs

Mains power varies all the time.
It is NEVER stable.

Measure the supply voltage and mains voltage.
Then calculate the supply voltage when mains is @ minimum and again for when mains is at maximum.
In the UK we use 216Vac to 254Vac. Europe is supposed to be the same range since we are supplied from the same harmonised supply.
 
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Anyway, there is no benefit in feeding more than 25V DCin over DCout so "burn" excess DCin on something useful like CRC pre-filtering than taxing the input MOSFET with dissipation that will decrease its reliability especially in tubes vicinity, which up the local ambient temperature.
 
Denmark have the same as sweden i think. Which means +-10% is said to be within limits... Of course it also depends on which phase you use, and how far from the transformer you are. So if you are living close to transformer you'll probably have a bit high voltage, and the other way if you live far from it. Also, as always everything depends on loading.
 
Let's make it a bit more simple.

If your nominal DC supply is 300Vdc and the mains varies by +-1% then the DC supply also varies by a tiny bit less than +-1%, i.e. +-3V

If your mains electricity supplier uses the full +-10% of mains voltage, that is expected in many Countries, then the DC supply will vary by just a tiny bit less than +-30V, i.e. from ~270Vdc to ~330Vdc

If your shunt regulator is set to an output voltage of 200Vdc, then when mains supply is at+10%, the CCS part of the regulator must dissipate [330-200] * 0.07 = 9.1W
The Shunt part when there is no load attached will dissipate 200 * 0.07 = 14W
The total dissipation will be 23.1W

When mains voltage is @ -10%, the CCS will see [270-200] = 70V across it.

You can change the transformer output to much lower voltage, based on this approximate method using +-10%.
 
AndrewT

I can follow you..must take care of the input volt

i will make my 300vdc different..by using crc to lower the volt...or buy a new trafo.

I can see a shunt is worse to high input volt,,than the Maida regulator..i use now

will compare those 2 just to see of there are any difference in sound

best bjarne
 
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This is a "super shunt" as they are called when having a CCS input. Its not a shunt reg's intrinsic demand, but an additional quality and safety feature. The 400V spec is because of the DMOS spec used. It is safety spec in this case because the part normally sees what is across it, not across to earth. There are higher VDS MAX parts but more capacitive usually.
 
Hello

Just finished my Salas sshv2--(thanks to Tea-Bag for super print)

Mounted the Salas with my new trafo (from Jms transformer) and 3 janzen filmcaps

first cap from rectifier is 33uf--100ohm--66uf--100ohm--66uf this give a output of
218vdc

and out of Salas 190vdc

Have compared the sound to My Maida regulator--they are close,but i will wait to i have play some more,,to give my full opinion

I use the Salas in my 4P1L preamp

And also thanks to Salas to made a great produkt

Best Bjarne
 
Noise on SSHV2 output

How much noise is to be expected (or is acceptable) on the regulated output of an SSHV2? I am still trying to chase down noise in both phono and line stages of my SVP, and have eliminated all the most obvious possibilities (grounding, hum pickup, etc). One thing that has occurred to me is the possibility of a noisy HT line: unlike the RTP3, the SVP has pretty low PSU rejection.

The PSU is shared between channels: it consists of a 300VAC transformer, 1N4007 bridge rectifier, followed by CLC (3uF, 10mH, 47uF). Each channel of the SVP draws about 30mA. What would an acceptable ripple be on the regulated outputs? A first measurement with a DVM (in the absence of a scope) gives around 3mV, which strikes me as quite high.

Alex