My take on a discrete shunt voltage regulator - Page 11

Melon Head · 3rd November 2009, 01:52 AM

Most of the guys doing this found they liked the sound of mosfets in the multiplier over bipolar transistors.

Salas · 3rd November 2009, 01:54 AM

Its prefiltering, so it can be good, why not. Don't know about the extra volts needed though if trafo is tight. CMC coils can be good too. I was thinking of a full power BJT cascode CCS instead of the mini only. That would take psrr performance higher for far higher frequencies. I was thinking of a depletion cascode too but then again not much internal feedback, or of an enhancement cascode with 10V Vgs + Vgs that is excellent, ala G. Pimm, could be done with leds, and will go HV too, but then again too much voltage loss. Or a cascode mosfet gyrator? What do you think? I guess will try and listen for a V1.2 at a point.

Melon Head · 3rd November 2009, 01:59 AM

I am not sure what is the best soution but a lot of guys liked the mosfet gyrator

Salas · 3rd November 2009, 02:07 AM

Cool, I have some boards from my preamp constant voltage load already. Will check in some step upgrade from 1.1 when time allows.

ikoflexer · 3rd November 2009, 02:07 AM

Yes, definitely just pre-filter. I would stay away from the lm317, I know other people use it, but it's just my preference.

For high frequency psrr everywhere I looked outside the audio field, guess what they use. Ferrite inductors, and common mode chokes. Simple, cheap, and efficient.

Then, two gyrators (or cap multipliers) in series, if one has enough juice in the transformer. There should be enough psrr even for the very obsessed. The noise getting in will probably be only that generated by the shunt reg itself, or modulated by the powered circuit.

ikoflexer · 3rd November 2009, 02:09 AM

Quote:

Originally Posted by Salas

Cool, I have some boards from my preamp constant voltage load already. Will check in some step upgrade from 1.1 when time allows.

Watch out, salas got the itch for action!

Salas · 3rd November 2009, 02:14 AM

Last time I got an itch, was the valve itch, and a phono came out.

Melon Head · 3rd November 2009, 02:15 AM

Keep right away from lm317

ikoflexer · 3rd November 2009, 02:18 AM

Talk about radio interference and its effect on audio stuff. here I quote the view of someone, from a presentation he made:

"The AudioFool Viewpoint
• The Myth: “We can hear stuff above 20 kHz”
• Reality: Some distortion mechanisms DO
produce audible artifacts from ultrasonic
signals, but we hear the problems, not the
signals!
• Intermodulation distortion (40kHz – 30kHz = 10 kHz)
• Slew rate limiting within electronics of
ultrasonic output of a mic (or of square
waves from a test generator)"

It's an entertaining document
http://audiosystemsgroup.com/Ferrites-Ham.pdf

ikoflexer · 3rd November 2009, 02:20 AM

who knows what will come out now?

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3rd November 2009, 01:52 AM	#101
Melon Head Formerly Thanh1973 Join Date: Nov 2006	Most of the guys doing this found they liked the sound of mosfets in the multiplier over bipolar transistors.

3rd November 2009, 01:54 AM	#102
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Its prefiltering, so it can be good, why not. Don't know about the extra volts needed though if trafo is tight. CMC coils can be good too. I was thinking of a full power BJT cascode CCS instead of the mini only. That would take psrr performance higher for far higher frequencies. I was thinking of a depletion cascode too but then again not much internal feedback, or of an enhancement cascode with 10V Vgs + Vgs that is excellent, ala G. Pimm, could be done with leds, and will go HV too, but then again too much voltage loss. Or a cascode mosfet gyrator? What do you think? I guess will try and listen for a V1.2 at a point.

3rd November 2009, 01:59 AM	#103
Melon Head Formerly Thanh1973 Join Date: Nov 2006	I am not sure what is the best soution but a lot of guys liked the mosfet gyrator

3rd November 2009, 02:07 AM	#105
ikoflexer diyAudio Moderator Join Date: May 2008 Location: Toronto	Yes, definitely just pre-filter. I would stay away from the lm317, I know other people use it, but it's just my preference. For high frequency psrr everywhere I looked outside the audio field, guess what they use. Ferrite inductors, and common mode chokes. Simple, cheap, and efficient. Then, two gyrators (or cap multipliers) in series, if one has enough juice in the transformer. There should be enough psrr even for the very obsessed. The noise getting in will probably be only that generated by the shunt reg itself, or modulated by the powered circuit.

3rd November 2009, 02:15 AM	#108
Melon Head Formerly Thanh1973 Join Date: Nov 2006	Keep right away from lm317

3rd November 2009, 02:18 AM	#109
ikoflexer diyAudio Moderator Join Date: May 2008 Location: Toronto	Talk about radio interference and its effect on audio stuff. here I quote the view of someone, from a presentation he made: "The AudioFool Viewpoint • The Myth: “We can hear stuff above 20 kHz” • Reality: Some distortion mechanisms DO produce audible artifacts from ultrasonic signals, but we hear the problems, not the signals! • Intermodulation distortion (40kHz – 30kHz = 10 kHz) • Slew rate limiting within electronics of ultrasonic output of a mic (or of square waves from a test generator)" It's an entertaining document http://audiosystemsgroup.com/Ferrites-Ham.pdf

3rd November 2009, 02:20 AM	#110
ikoflexer diyAudio Moderator Join Date: May 2008 Location: Toronto	who knows what will come out now?

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