Simplistic Mosfet HV Shunt Regs - Page 346

merlin el mago · 18th November 2012, 11:14 AM

Do you know how to make a simplistic +50V PSU?

merlin el mago · 18th November 2012, 12:01 PM

Can I do it with a LM317?

Salas · 18th November 2012, 12:56 PM

You just need some +DC voltage to test the CCS independently I understand. So whatever you got up to 50V (to keep dissipation under control) its OK. Be it batteries, LM317, bench PSU, whatever. It could be 12V even.

merlin el mago · 18th November 2012, 01:13 PM

OK I will do.

king4joy · 18th November 2012, 03:08 PM

A new Salas SSHV2??!!! Please keep us posted.

Tea-Bag · 18th November 2012, 04:02 PM

Quote:

Originally Posted by king4joy

A new Salas SSHV2??!!! Please keep us posted.

That would be a SSHV3

Really, no idea.

Salas · 18th November 2012, 04:25 PM

Merlin's photo where the still unpopulated C1 pads can be clearly seen is an opportunity to remind something for when constructing. Only the two left hand pads are to accept C1's one leg, all the others to the right are to accept its other leg. They are staggered for various standard pitch capacitors that you may find. Watch the legs to always span the left black gap in the picture in other words, and keep the cap just a wee bit proud off board for its underside not to touch any free pads, its important.

@KingForJoy
That ain't any new SSHV2, its just Merlin's yet another SSHV2 build.

Jogi · 18th November 2012, 04:51 PM

o.k., I just feel the need to get out the sledge hammer for treating my SSHV2 built

Its for my D3a phono preamp, which played nicely with the first version of the shunt. I then set up the SSHV2, clearly better...and then I accidently shorted the input, and from then I replaced 3 sets of semis and couldn't get it running again. Ruined the PCB of course during the process.
Then I asked a friend to let go of one of his spare shunt PCB, ordered new semis and populated everything completely new; worked fine yesterday from the beginning.
When trying to mount it in the encosure, I again shorted the input accidently! (by just one strand of the wire which was peeking out of the bundle)

Before I had 290V input / 240v out set at 50mA, tubes eating 25mA.
Now when I set the current to 50mA, the input voltage drops to 243V, out still at 240.
When setting current to 30mA, input gets up to 280V again, but current ist too low.
And in either way the IRF840 is getting pretty hot, so something is eating a lot of current here.

I still can adjust both trimmers, and I already replaced Q1 to no avail.

Before I order new semis AGAIN and tear everything apart and replace all semis AGAIN, does anyone has a hint where to look first?

Maybe you know the feeling when you just want to open that window and get rid of the problem the easy way

Salas · 18th November 2012, 05:04 PM

Replace C1, after that C2, see if it behaves any better, maybe they got a hit inside the windings. Inspect with a strong light and/or magnifier when installing HV stuff. Two times shorting is big jinx.

Jogi · 18th November 2012, 05:08 PM

Yes, really bad kinda magic...
Thanks Salas, I'll try the last remaining semi for Q2, hoping for the best...

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18th November 2012, 11:14 AM	#3451
merlin el mago diyAudio Member Join Date: Sep 2009 Location: Catalonia new Europe state	Do you know how to make a simplistic +50V PSU?

18th November 2012, 12:01 PM	#3452
merlin el mago diyAudio Member Join Date: Sep 2009 Location: Catalonia new Europe state	Can I do it with a LM317?

18th November 2012, 12:56 PM	#3453
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	You just need some +DC voltage to test the CCS independently I understand. So whatever you got up to 50V (to keep dissipation under control) its OK. Be it batteries, LM317, bench PSU, whatever. It could be 12V even.

18th November 2012, 01:13 PM	#3454
merlin el mago diyAudio Member Join Date: Sep 2009 Location: Catalonia new Europe state	OK I will do.

18th November 2012, 03:08 PM	#3455
king4joy diyAudio Member Join Date: Apr 2011	A new Salas SSHV2??!!! Please keep us posted.

18th November 2012, 04:51 PM	#3458
Jogi diyAudio Member Join Date: Jan 2008	o.k., I just feel the need to get out the sledge hammer for treating my SSHV2 built Its for my D3a phono preamp, which played nicely with the first version of the shunt. I then set up the SSHV2, clearly better...and then I accidently shorted the input, and from then I replaced 3 sets of semis and couldn't get it running again. Ruined the PCB of course during the process. Then I asked a friend to let go of one of his spare shunt PCB, ordered new semis and populated everything completely new; worked fine yesterday from the beginning. When trying to mount it in the encosure, I again shorted the input accidently! (by just one strand of the wire which was peeking out of the bundle) Before I had 290V input / 240v out set at 50mA, tubes eating 25mA. Now when I set the current to 50mA, the input voltage drops to 243V, out still at 240. When setting current to 30mA, input gets up to 280V again, but current ist too low. And in either way the IRF840 is getting pretty hot, so something is eating a lot of current here. I still can adjust both trimmers, and I already replaced Q1 to no avail. Before I order new semis AGAIN and tear everything apart and replace all semis AGAIN, does anyone has a hint where to look first? Maybe you know the feeling when you just want to open that window and get rid of the problem the easy way

18th November 2012, 05:04 PM	#3459
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Replace C1, after that C2, see if it behaves any better, maybe they got a hit inside the windings. Inspect with a strong light and/or magnifier when installing HV stuff. Two times shorting is big jinx.

18th November 2012, 05:08 PM	#3460
Jogi diyAudio Member Join Date: Jan 2008	Yes, really bad kinda magic... Thanks Salas, I'll try the last remaining semi for Q2, hoping for the best...