Simplistic Mosfet HV Shunt Regs - Page 5

Salas · 17th December 2008, 06:54 PM

Not really, use red. The greens group better statistically, that is all. You use so little CCS current in your case, that if you get some more or less, there will be no dissipation or starvation penalty.

cygnus x1 · 17th December 2008, 07:10 PM

I got to listen to the HV shunt late last night, background is "blacker", overall sound is faster without harshness, voicing and timber has improved. I'm running one per channel in the line stage. Needless to say the Lambda No. 28 is now up for sale. Didn't think anything would beat the LCLCLC filter and the No. 28. I have tried the Allen Wright SuperReg and the Janus, both have ICs. While both are very good, I prefer the KISS approach and it does sound better. Anyone who is looking for a GREAT simple shunt regular, this IS the way to go. Again a big "thanks" to Salas.

inertial · 18th December 2008, 08:39 AM

Cygnus,
very interesting comment!
So, the Salas's regulators sound better even of a chocke input PSU ?
This is very good news.
I have searched this "Lambda n 28" but no result. Can you please post a link ?
Thanks

Cheers,
Paolo

Stixx · 18th December 2008, 10:05 AM

Just started going through my parts bin to collect parts for a hv shunt build (over xmas?) and checking what will have to be ordered.
I am having a bit of a hard time determining the size of the mosfet heatsinks...(my application B+ ~200V max at 36mA).
Trying to read up on the subject turns up very scientific explanations at great lenght, but sure there is some handy formula for this...

Will a heatsink with 2.5K/W be enough (120x32x50mm)??

Salas · 18th December 2008, 11:50 AM

Yes, that heat sink should be enough for your application.

cygnus x1 · 18th December 2008, 01:03 PM

inertial
The Lambda No. 28 is a vintage labratory tube p/s regulator from the 50s (lambda is still producing lad grade p/s). Kind of like the Kepco. I was going to post it in the marketplace, once I found the documentation and schmatic. Email me and I can send you a picture and I will dig through my files to find the docs.
Compaired to the Salas HV shunt, it is more conjested sounding, not as fast, not as "black" in the background. The fact that it is a series regulator, puts a lot of components in the HV rail, along with the all the inductors and caps, muddies up the HV rail (all that inductance and phase shift from the caps).
My line stage (type 340 DHT, CCS, parafeed OPT) is very revealing and dependant on a clean, stable, low noise and low inpeadance supply. Because it has a high plate resistance, I wouldn't even try to run this tube without the CCS and parafeed OPT, the typical resistance loaded, cap coupled output, just doesn't "sing". Give the Salas HV Shunt a listen.

inertial · 18th December 2008, 01:19 PM

Oh, thanks cygnus,
I understand. I have talked with my fiend and he is disponible to
make a Sala's prototipe circuit for me. Unfortunately he is very busy at the moment but he hope to find a bit of time to make it into acceptable time...........I hope the same!

cheers,
Paolo

Stixx · 21st December 2008, 08:59 AM

Salas,

what is the expected voltage drop across the regulator?
I don't want to burn excessive voltage in the heatsinks and size the transformer accordingly...

Thank you...

Salas · 21st December 2008, 09:03 AM

I would like you to drop 50V because it sounds better. But it can work from as low as 10V drop.

Stixx · 21st December 2008, 12:05 PM

alrighty... 50V it will be then.

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17th December 2008, 06:54 PM	#41
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Not really, use red. The greens group better statistically, that is all. You use so little CCS current in your case, that if you get some more or less, there will be no dissipation or starvation penalty.

17th December 2008, 07:10 PM	#42
cygnus x1 diyAudio Member Join Date: Sep 2006	I got to listen to the HV shunt late last night, background is "blacker", overall sound is faster without harshness, voicing and timber has improved. I'm running one per channel in the line stage. Needless to say the Lambda No. 28 is now up for sale. Didn't think anything would beat the LCLCLC filter and the No. 28. I have tried the Allen Wright SuperReg and the Janus, both have ICs. While both are very good, I prefer the KISS approach and it does sound better. Anyone who is looking for a GREAT simple shunt regular, this IS the way to go. Again a big "thanks" to Salas.

18th December 2008, 08:39 AM	#43
inertial diyAudio Member Join Date: Aug 2004 Location: Italy	Cygnus, very interesting comment! So, the Salas's regulators sound better even of a chocke input PSU ? This is very good news. I have searched this "Lambda n 28" but no result. Can you please post a link ? Thanks Cheers, Paolo

18th December 2008, 10:05 AM	#44
Stixx diyAudio Member Join Date: Sep 2003 Location: Southern Germany	Just started going through my parts bin to collect parts for a hv shunt build (over xmas?) and checking what will have to be ordered. I am having a bit of a hard time determining the size of the mosfet heatsinks...(my application B+ ~200V max at 36mA). Trying to read up on the subject turns up very scientific explanations at great lenght, but sure there is some handy formula for this... Will a heatsink with 2.5K/W be enough (120x32x50mm)??

18th December 2008, 11:50 AM	#45
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Yes, that heat sink should be enough for your application.

18th December 2008, 01:03 PM	#46
cygnus x1 diyAudio Member Join Date: Sep 2006	inertial The Lambda No. 28 is a vintage labratory tube p/s regulator from the 50s (lambda is still producing lad grade p/s). Kind of like the Kepco. I was going to post it in the marketplace, once I found the documentation and schmatic. Email me and I can send you a picture and I will dig through my files to find the docs. Compaired to the Salas HV shunt, it is more conjested sounding, not as fast, not as "black" in the background. The fact that it is a series regulator, puts a lot of components in the HV rail, along with the all the inductors and caps, muddies up the HV rail (all that inductance and phase shift from the caps). My line stage (type 340 DHT, CCS, parafeed OPT) is very revealing and dependant on a clean, stable, low noise and low inpeadance supply. Because it has a high plate resistance, I wouldn't even try to run this tube without the CCS and parafeed OPT, the typical resistance loaded, cap coupled output, just doesn't "sing". Give the Salas HV Shunt a listen.

18th December 2008, 01:19 PM	#47
inertial diyAudio Member Join Date: Aug 2004 Location: Italy	Oh, thanks cygnus, I understand. I have talked with my fiend and he is disponible to make a Sala's prototipe circuit for me. Unfortunately he is very busy at the moment but he hope to find a bit of time to make it into acceptable time...........I hope the same! cheers, Paolo

21st December 2008, 08:59 AM	#48
Stixx diyAudio Member Join Date: Sep 2003 Location: Southern Germany	Salas, what is the expected voltage drop across the regulator? I don't want to burn excessive voltage in the heatsinks and size the transformer accordingly... Thank you...

21st December 2008, 09:03 AM	#49
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	I would like you to drop 50V because it sounds better. But it can work from as low as 10V drop.

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21st December 2008, 12:05 PM	#50
Stixx diyAudio Member Join Date: Sep 2003 Location: Southern Germany	alrighty... 50V it will be then.