The simplistic Salas low voltage shunt regulator

[Salas]

Originally Posted by HiFiNutNut

I have never played it for more than one hour, what if it continues to drop?

You got to monitor it and wait for more and known quality jfets, I agree. Maybe it is not really a problem if it steady settles somewhere. Just trim the positive side after the neg settles and leave it there. Now if it continues sliding after some more hours, you better match a couple of jfets from the new ones you gonna get and put them in. That will show if it was the jfet. I am also wondering about actually setting a +/-V match using the trimmers for somewhat higher voltage after 10-20 mins as I wrote above. Are they really steady 0 when fully closed? Its a plausible question. There are minute moving parts in there, and the heat around them changes with time, as the shunts run.

[HiFiNutNut]

The njfet is not near the heatsink at all. However, the 150R gate stopper is indeed lying across the MOSFET and the heatsink very close only on the negative side.

OK. I will try the trimpots.

The "sensing capacitor" is made up from a 1.1uF MKP || 100uF electrolytic. I am not too comfortable with that arrangement. It is much better to have the film capacitor only. I may try taking out the electrolytic and see how it sounds. If it sounds better, I may select a higher current 2SK170 to increase the impedance to allow a lower corner frequency (and I know you are against higher impedance due to damping factor, etc, but this increase is not really too much). Or perhaps use a different part like the BF244B that can give 15mA current? Would BF244B fit here? I have a dozen of them not used. Or I may try taking out the film cap, or I may increase the 100uF.

I will also play with different capacitance of the output capacitor and select the best value. I expect this will make some difference.

I think it is time for me to go for another 1 hour listening then try the various things. I guess I may be too lazy to do such mods while enjoying music. It may even take me a few days to find the result.

[Salas]

Since it basically works plus it sounds good to you, you have certainly succeeded. Thinking that you firstly implemented a symmetrical V1.1 and gave us feedback plus you have shown a working layout, you also broke new testing ground. Thanks for the tests. Good contribution.

As for finding your favorite sound for various capacitors used, as for picking values and qualities, this is something that has to do a lot with you and the synergy in the system. Me I prefer around 470uF over the resistive Vref element, but its on another circuit and system. Listen to music. Thanks again. Whatever you arrive to, certainly people in the thread would like to know. Me I would like to see a picture, especially because it has the buffers and I know it will help anybody that will attempt them by looking at your layout, because the high Hfe 300mHz BJTs they can be tricky at a capacitive gate. Seen that with p2p when I added 2 buffers in positive V1's.

P.S. Looked at BF244B. Says pinch off starts low in its datasheet, if it is actually around -0.5V for the ones you pick it will work steady, else if -1V or more it will play. Also its an RF part, I hope it will behave for showing any instability tendencies. Using the 244 its something that you have to test in practice really.

[HiFiNutNut]

Just came back from more listening. Confirmed that it sounds better than other regs I have tried, or should I say, I prefer it over any others I tried. It sounds more "RIGHT" than all others. But I also believe that I still need to put in up to a couple of weeks time to optimize it as there are areas of improvements I can address. It has been a full day for me and I should retire from it now. I feel a bit burnt-out now and will approach it (tune it) slowly in the coming days and post the results in perhaps 2 weeks time, while preparing to build v2. But since I don't have the full range speakers to listen to because I don't have my line level XO/EQ yet and I only temporarily wired up a less than ideal passive XO and ran only the MTM part of the MTMWW+Sub, I am tempted to use the v1 / preamp to do driver /room final measurements, so that I can listen to my "glorious" full range speakers. Perhaps I could then do better tests on my regulators. I will see which way I will go.

[HiFiNutNut]

As for pictures, it is late at night in Sydney now. I will do it in the coming days.

The picture of my speakers is already made so here it is. It does depend on the regulator to sing.

The tweeter is the very best of the top of the range Dynaudio's Esotar T330D, capable of 1000W transient with 93dB sensitivity used 2k and above. The Midranges are twin ScanSpeaker 6.5" revelators 18W8531G00, the best measured by Zaph, housed in Open back U-frame, used from 180Hz up. There are twin 10" Scanspeak revelators 26W8861T00 in seperate U-frames used from 60Hz up. The subwoofers are not in the picture. They are Peerless XLS 12" in monopoles.

[Telstar]

Originally Posted by HiFiNutNut

I guess I will wait until I build v2

Can somebody post the scheme of v2?
Thanks.

[Salas]

Originally Posted by HiFiNutNut

As for pictures, it is late at night in Sydney now. I will do it in the coming days.

The picture of my speakers is already made so here it is. It does depend on the regulator to sing.

Beautiful.

[ikoflexer]

Originally Posted by Telstar

Can somebody post the scheme of v2?
Thanks.

telstar, just look a few pages ago. It's there.

[Telstar]

Originally Posted by ikoflexer

telstar, just look a few pages ago. It's there.

I just want to be sure which one is v2.
I found yours, the original from Salas, the one for DAC... I checked from pg120..

[Greg Erskine]

IRFP240&IRFP9240 power amplifier schematic