Simplistic Mosfet HV Shunt Regs - Page 219

vgeorge · 22nd December 2011, 07:37 PM

Not right at the input, say 15cm. First killed the oscillation with a 56ohm resistor and then tried a 47uF capacitor I had in hand. It was closer to pick up! Everything was with alligator clips and cables not twisted or anything.
It would be better at the input, but as I sorted it out, I did not investigate more.

Salas · 22nd December 2011, 07:39 PM

How far is the original rectification + filtering? A resistor is a good inexpensive means also if there is much loop inductance meeting the input. But you will have to see if it needs anything at all in the final installation.

merlin el mago · 22nd December 2011, 07:40 PM

Quote:

Originally Posted by vgeorge

Power transformer 2x220V, 5R4GY rectifier, choke input ll1673, ll1660PP for output transformer and AVC from Intact audio.
Also got some nice BIG 10ohm 100W Dale resistor for filament bias.

Where did you bought the resistors?

vgeorge · 22nd December 2011, 08:31 PM

leads were 1m. Final layout will have caps near the regs.
Phillipe, I bought these from ebay some time ago. If you want will search and tell you tomorrow.

king4joy · 23rd December 2011, 05:47 AM

Salas, and vgeorge....I will have long cables too...between the SSHV2 (in the power supply box) and the 2 CCS's (in the amp box) loading the VT25....where and how should I do the decoupling please??

vgeorge · 23rd December 2011, 06:23 AM

Just put the last cap close to the input of the regulator.
As I understand, you have the regulator in another box from the pre, which is not optimal, but given that you use 4 wires output, it won' t matter much.

king4joy · 23rd December 2011, 06:51 AM

Yes, I need to put the SSHV2 (only one to start) in the PSU box....as there is not much space left in the amp box....I am using a pair of Rod Coleman's board for the filament...

vgeorge · 23rd December 2011, 07:36 AM

Are you going with one or two SSHV2?
One could fit easily, two if vertical maybe?

king4joy · 23rd December 2011, 07:44 AM

I am going with only one SSHV2 for now to try....your boards seem quite small...are you using 10uF for C2??....and are you using heat sink on Q1 and Q6 as well...does Q6 need a sink as well??

vgeorge · 23rd December 2011, 07:57 AM

Heatsink on Q1 and Q3 only. Yes, 10uF Solen 250V.

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22nd December 2011, 07:37 PM	#2181
vgeorge diyAudio Member Join Date: Mar 2004 Location: poros island	Not right at the input, say 15cm. First killed the oscillation with a 56ohm resistor and then tried a 47uF capacitor I had in hand. It was closer to pick up! Everything was with alligator clips and cables not twisted or anything. It would be better at the input, but as I sorted it out, I did not investigate more.

22nd December 2011, 07:39 PM	#2182
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	How far is the original rectification + filtering? A resistor is a good inexpensive means also if there is much loop inductance meeting the input. But you will have to see if it needs anything at all in the final installation.

22nd December 2011, 08:31 PM	#2184
vgeorge diyAudio Member Join Date: Mar 2004 Location: poros island	leads were 1m. Final layout will have caps near the regs. Phillipe, I bought these from ebay some time ago. If you want will search and tell you tomorrow.

23rd December 2011, 05:47 AM	#2185
king4joy diyAudio Member Join Date: Apr 2011	Salas, and vgeorge....I will have long cables too...between the SSHV2 (in the power supply box) and the 2 CCS's (in the amp box) loading the VT25....where and how should I do the decoupling please??

23rd December 2011, 06:23 AM	#2186
vgeorge diyAudio Member Join Date: Mar 2004 Location: poros island	Just put the last cap close to the input of the regulator. As I understand, you have the regulator in another box from the pre, which is not optimal, but given that you use 4 wires output, it won' t matter much.

23rd December 2011, 07:36 AM	#2188
vgeorge diyAudio Member Join Date: Mar 2004 Location: poros island	Are you going with one or two SSHV2? One could fit easily, two if vertical maybe?

23rd December 2011, 07:44 AM	#2189
king4joy diyAudio Member Join Date: Apr 2011	I am going with only one SSHV2 for now to try....your boards seem quite small...are you using 10uF for C2??....and are you using heat sink on Q1 and Q6 as well...does Q6 need a sink as well??

23rd December 2011, 07:57 AM	#2190
vgeorge diyAudio Member Join Date: Mar 2004 Location: poros island	Heatsink on Q1 and Q3 only. Yes, 10uF Solen 250V.