I think they may be talking about something like this http://www.wenzel.com/documents/finesse.html or similar
chalky said:
I don't think it is a copy of Charlie Wenzels finnesse reg,
the OP Z is too low.
But why do I keep getting the feeling it is based on a
negative impedance generator, sort of like the
Hawksford OP error correction scheme.
Very low OP Z, very good BW, very good stability unlike
opamp based designs that use lots of OLG to get low OP
Z.
I can feel a new reg coming on.
Cheers,
Terry
The pcb is a multilayer board with gilt (thin gold layer) pads, AD797, IRL3502, ADR425(?). It's a mystery why they have chosen a 20 volt mosfet 
OS-CON as input and output caps. Black gate as LP-filter for the voltage reference and for the feedback. Very small melf resistors and 0402. 42 x 54 mm, very cute.
The topology seems to be a conventional Sulzer regulator.
OS-CON as input and output caps. Black gate as LP-filter for the voltage reference and for the feedback. Very small melf resistors and 0402. 42 x 54 mm, very cute.
The topology seems to be a conventional Sulzer regulator.
I change my mind, it's not a Sulzer regulator, it's a Jung Super regulator but not with the enhanced emitter follower. The design is more or less identical with the article Jung wrote
http://home.comcast.net/~walt-jung/wsb/PDFs/Low_Noise_Power_for_Analog_Circuits.pdf
but since they use a mosfet the driving is different. Resistor between drain and gate and from gate a 6.8 V zener down to the opamp output.
Voltage reference is ADR421 (2.5 volts), which seems to be a good choice according to datasheet.
All and all I think it looks good but I'll doubt it is as good as Walt Jung's enhanced model with class A emitter follower and fast bipolar transistors.
A fat OS-CON 330 uF is at the output and I think we come to the conclusion that big and good elelctrolytics didn't do any "more" good, more like harm in some cases.
I wonder if a Black Gate as LP-filter for DC is for making the BG crowd pleased?
http://home.comcast.net/~walt-jung/wsb/PDFs/Low_Noise_Power_for_Analog_Circuits.pdf
but since they use a mosfet the driving is different. Resistor between drain and gate and from gate a 6.8 V zener down to the opamp output.
Voltage reference is ADR421 (2.5 volts), which seems to be a good choice according to datasheet.
All and all I think it looks good but I'll doubt it is as good as Walt Jung's enhanced model with class A emitter follower and fast bipolar transistors.
A fat OS-CON 330 uF is at the output and I think we come to the conclusion that big and good elelctrolytics didn't do any "more" good, more like harm in some cases.
I wonder if a Black Gate as LP-filter for DC is for making the BG crowd pleased?
where's the "additional" compensation for the AD797 (per Analog Devices datasheet) ? -- as we know this is a tricky opamp to work with. In issue 4/2000 of Audio Amateur Walt Jung recommended the AD825 or AD817 insead of the AD797.
I recall that in the original Audio Amateur articles there was a sidebar conversation by Galo: "So It Oscillates, Now What ?" (4/95)
I do hope, for the sake of general knowledge, that the people at Old Colony Sound make a CD-ROM for the 1980's and 1990's -- the ARRL folks do this for QST and QEX, as well as Circuit Cellar
I recall that in the original Audio Amateur articles there was a sidebar conversation by Galo: "So It Oscillates, Now What ?" (4/95)
I do hope, for the sake of general knowledge, that the people at Old Colony Sound make a CD-ROM for the 1980's and 1990's -- the ARRL folks do this for QST and QEX, as well as Circuit Cellar
The regulator oscillates at 4 MHz, 20 mV peak, if you attach 100 nF right at the output pins and load it with some current 750 mA in my case.
The thing is that the oscillation goes away with on 10+10 mm wire so this is hardly an issue.
The AD797 seems to run without any special treatment. Don't forget that the pcb is 4-layer board so you will have pretty good ground.
AD825 seems to be a better choice and the noise will get slightly higher. I have measured around 5 uV with AD825 which I think is pretty good and by that you'll will have a more "pure" performance, phasewise.
BTW: The Black Gate is 100 nF which seems to be a mystery to choose instead of someting good, non-electrolythic.
The thing is that the oscillation goes away with on 10+10 mm wire so this is hardly an issue.
The AD797 seems to run without any special treatment. Don't forget that the pcb is 4-layer board so you will have pretty good ground.
AD825 seems to be a better choice and the noise will get slightly higher. I have measured around 5 uV with AD825 which I think is pretty good and by that you'll will have a more "pure" performance, phasewise.
BTW: The Black Gate is 100 nF which seems to be a mystery to choose instead of someting good, non-electrolythic.
Standard type stuff 
. Ultra low noise / ripple / distortion, fast, wide bandwidth supply to run an outboard D/A converter. I have a bunch of LT1085 chips hanging around, and Fairchild soft recovery diodes of the proper rating so I wanted to at least be able to use those. I also have an R-Core 40 VA transformer that I'm hoping will be a nice fit into this supply. What other info can I supply that may be of help?
. Ultra low noise / ripple / distortion, fast, wide bandwidth supply to run an outboard D/A converter. I have a bunch of LT1085 chips hanging around, and Fairchild soft recovery diodes of the proper rating so I wanted to at least be able to use those. I also have an R-Core 40 VA transformer that I'm hoping will be a nice fit into this supply. What other info can I supply that may be of help?
When using a three pin ready made "super regulator" like the Audiocom Super Regulators, does it require any special implementation or is it best to just drop them in as a replacement to the existing regulator without changing any of the surrounding components?
The regulators supplying the TDA1541A in my Arcam CDP have various values of capacitors before and after them. Should I retain those values?
The regulators supplying the TDA1541A in my Arcam CDP have various values of capacitors before and after them. Should I retain those values?
The adjust pin of Z203 -- which is a pre-regulator and also works the protection circuitry -- you could put a 100uF electrolytic here -- minding the polarity.
I think that you would find that deriving the voltages from a pair of Old Colony Jung/Didden regulator boards to be a far less expensive alternative -- and WJ and Jan did a lot of work vetting the process -- so you aren't buying a pig-in-a-poke.
Audiocom seems to offer no supporting evidence that their board outshines the WJ Super Regulator, and at $185/pop is it worth it for something which hasn't been vetted? No Line Rejection stats, no noise stats, no impedance stats. Perhaps I am missing some page on their website, correct me if I am wrong.
The boards are only $24 for a set, the components are all available at Digikey -- I have had no oscillation problems with the AD797, AD825ar, LT1115 used as error amplifier. They even send you a copy of the original article from The Audio Amateur.
I think that you would find that deriving the voltages from a pair of Old Colony Jung/Didden regulator boards to be a far less expensive alternative -- and WJ and Jan did a lot of work vetting the process -- so you aren't buying a pig-in-a-poke.
Audiocom seems to offer no supporting evidence that their board outshines the WJ Super Regulator, and at $185/pop is it worth it for something which hasn't been vetted? No Line Rejection stats, no noise stats, no impedance stats. Perhaps I am missing some page on their website, correct me if I am wrong.
The boards are only $24 for a set, the components are all available at Digikey -- I have had no oscillation problems with the AD797, AD825ar, LT1115 used as error amplifier. They even send you a copy of the original article from The Audio Amateur.
In their defense, they have been selling on Ebay for at least the last 9 months or so for £16.99 which is why I bought two super regs and one invisus (slightly more expensive). They seem to sell the old models on Ebay along with their rather expensive CD player mods.
I agree though, should have made my own.
I wouldn't buy any more and certainly not at the list price
I agree though, should have made my own.
I wouldn't buy any more and certainly not at the list price
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