That Transformer voltage and regulator arrangement works excellently. Transformers should be at least 25 VA.
I'm back with further questions..🙂 yes I know its irritating..
Okay the pondering over the psu took a sharp turn when I visited the diyaudio store, I believe I drolled on my shirt when I saw the jung/didden regulator, hmm, clean dc, low impedance, all over the spectrum, what more could a boy want for Christmas?, soooooo those 7815/7915 oldtimers would need to go back to the drawer in shame or stay in?
Okay the pondering over the psu took a sharp turn when I visited the diyaudio store, I believe I drolled on my shirt when I saw the jung/didden regulator, hmm, clean dc, low impedance, all over the spectrum, what more could a boy want for Christmas?, soooooo those 7815/7915 oldtimers would need to go back to the drawer in shame or stay in?
Scroll back through the previous 3-4 months' worth of messages on this thread. You'll find that at least one Pearl3 builder & participant in this thread, has replaced the IC voltage regulator chips with Jung/Didden Super Regulators; I don't remember whether they're using the diyAudio Store Super Regulator PCBs or some other implementation.
That would be me. Pre-regulators with LM3x7 to about 20.5V, then super regs to 15V. I used the Diyaudio store boards. Still have to put everything together though. Took some time to have custom chassis made, and still waiting for a second transformer from Toroidy (made the costly mistake of first ordereing one with too little overhead voltage for the dual regulation.)
To successfully operate the ensemble mentioned in #3946, I myself would want a transformer with 2x19VAC or 2x20VAC secondaries, giving (in my opinion) adequate margin of safety. Since it's "just a phonostage" drawing very few Volt-Amperes, you wouldn't pay significantly more money to go up even further (safer) to 2x22VAC. But your preregulators would get hotter and require bigger heatsinks as you increased the secondary AC voltage.
First ordered 2x17V but that provided not enough overhead. I calculaterd with 17% regulation, but that drops to about 0% under some load. Now I ordered 2x22V. Any higher would have gotten too close to the 40V of my caps. Jan Didden recommends 5V margin for best performance of the super reg. I also estimate around that for the LM 3x7's.
Also, Walt Jung believes in some load (100 mA) for low output impedance, so I will add some load resistors to the Pearl (270 Ohm 3W).
Very useful information you provide, I was not aware that the super reg operates best beyond 100ma.
Do you have an opinion as to any sound improvement, standard verses the super reg?.
I can see it getting more complex, housing restrictions etc, I'm also dead set on external toggle switches, also more complication, sixteen switches to cartridge loading, one dual switch for gain, and one on/off,
Do you have an opinion as to any sound improvement, standard verses the super reg?.
I can see it getting more complex, housing restrictions etc, I'm also dead set on external toggle switches, also more complication, sixteen switches to cartridge loading, one dual switch for gain, and one on/off,
If you are using the dual chassis system, the power supply module could be relatively simple. As long as the output of your PSU is stable and above about 18VDC, the on board regulators on the Pearl 3 will have enough overhead to work properly. And they do work well. The supplied CRCRC setup work well.
I have the transformer-rectifiers, snubber and CRCRC in a seperate enclosure. Both regulators are in the Pearl 3 enclosure (I'm using a much bigger one than the stock enclosures).
Will it sound better? Well, measurements others have done show that the 7x15's are doing just fine, so I doubt I would hear a difference, but there is no way for me to test this. It's just the idea that clean power is important for a phono pre, and this is just a step up. The UDP from Mark Johnson is another way to achieve that. I also have the Pearl 2, l'm looking forward to a comparison. My Pearl 2 has Sparkos discrete 24V regulators instead of the 7x24's. That would also be an easier way to spice up the Pearl 3 a bit: Sparkos 15V regulators in stead of 7x15's. Not cheap though.
Will it sound better? Well, measurements others have done show that the 7x15's are doing just fine, so I doubt I would hear a difference, but there is no way for me to test this. It's just the idea that clean power is important for a phono pre, and this is just a step up. The UDP from Mark Johnson is another way to achieve that. I also have the Pearl 2, l'm looking forward to a comparison. My Pearl 2 has Sparkos discrete 24V regulators instead of the 7x24's. That would also be an easier way to spice up the Pearl 3 a bit: Sparkos 15V regulators in stead of 7x15's. Not cheap though.
UDP3's big idea is: make sure nothing bad gets onto the umbilical cable. Get rid of high frequency noise, mains frequency noise ("hum"), audio frequency noise, and extremely low frequency noise. Filter them out and stop them dead, within the PSU chassis; keep them off the umbilical cable. What does go on the cable, and what flows into the separate Pearl3 amplifier chassis 1.5 meters away, is ultra-filtered and high purity DC. Make life easier for the voltage regulator ICs on the Pearl3 amplifier boards, by giving them pure DC inputs. UDP3 proudly uses lots of parts and lots of PCB area, thus it doesn't exhilarate minimalists.
That is a very complex pcb you put together there, I will dig into your thread, I also looked into lion battery packs.
@amplidude
there's also the silent switcher option...
almost enough interesting possibilities to implement "plug and play" to try 'em all.
there's also the silent switcher option...
almost enough interesting possibilities to implement "plug and play" to try 'em all.
Looking at Q1-Q4... Current seems to be from 2.5mA; has anyone measured or simulated Vds for Q1-Q4?
Thank you @wayne for this wonderful and very good sounding phono preamp and thank you @Dneu2011 for making it and sending to me 🙂
I did some extensive listening with my Lenco L70 TT with 3 tonearms (standard, Lenco P77 and Rabco) and the carts Stanton 500 (red dot), Stanton 680 (SA DJ needle from Florida), Nagaoka MN-22, Elac STS 222, B&O SP, Decca London a. o.
After 50 hrs+ break in time I did engage dip switch 8 (default setting) and the use of the switches 6 and 7 was very helpful. I've never heard these subtle differences between carts and needles so good and how the music comes out of the groove is just wonderful, makes great fun!!!
I did some extensive listening with my Lenco L70 TT with 3 tonearms (standard, Lenco P77 and Rabco) and the carts Stanton 500 (red dot), Stanton 680 (SA DJ needle from Florida), Nagaoka MN-22, Elac STS 222, B&O SP, Decca London a. o.
After 50 hrs+ break in time I did engage dip switch 8 (default setting) and the use of the switches 6 and 7 was very helpful. I've never heard these subtle differences between carts and needles so good and how the music comes out of the groove is just wonderful, makes great fun!!!