Re: Re: Re: Why etc
I had studied the Jumg regs performance years ago when
they were published in Audio Amateur. I directly compared
a discrete low open loop gain reg I designed myself and
it was lower OP Z than the graphs on AA above a few hundred
kHz. I can't remember the exact measurements, it was years ago,
but they were definately MUCH wider BW than the Jung regs.
The OP Z of my regs were in the order of 0.05ohms out to
1 mHz without any OP cap in place.
WRT to flatness, it is only an indication that the reg has
very wide BW and good settling time. If you look at opamps,
the ones with best settling time are always low open loop gain,
less internal stages and very fast.
Just as I readily accepted that YOU heard a difference when
reading about listening tests in AA. What makes you right and
me and others wrong? What makes your listening tests unbiased?
I tested my regs with some NON TECHNICAL listeners who didn't
even know what feedback was and observed their opinions,
totally free of placebo. So, whereas my judgement could have
been biased, they only wanted the best sound for their DAC...
and I gave them whichever iteration they preferred... often
my reaction was "why does this sound better". Often there
are more questions than answers. At least I am honest about it!
It seems you feel most people here use open loop + trannies
for I-V due to a lack of OPA implemetational knowledge, deluding
ourselves that we have made a sonic improvement? Do you
think we are so stupid? Do you not think that many of us
have tried the venerable AD811 and countless others with
countless power supply iterations and THEN decided to move
on to more fruitful ground from shear frustration.
You may find it interesting that one of the biggest innovators in
digital, Apogee Digital, used zero feedback discrete I-V on
the DA1000. This was the one repackaged by Mark
Levinson for Cello (same I-V). Wadia also has their own style of
ZFB I-V on their ultra expensive DACs.
Then there's Mr Edmund Meitner, know him.... he also seems to
be a proponent of ZFB DAC AND ADC interface on his incredibly
highly regarded and measuring converters.
Jan, I have a lot of respect for your work and read very
carefully all the articles on the super regs. They were very well
done, represented a huge amount of work and I learnt a lot from
them. I applaud your effort!
But could you please do some of us the favour of
acknowledgment of our existence... there are also some other
people here who have much to contribute
to this so very challenging of pursuits.
Terry
janneman said:
I had studied the Jumg regs performance years ago when
they were published in Audio Amateur. I directly compared
a discrete low open loop gain reg I designed myself and
it was lower OP Z than the graphs on AA above a few hundred
kHz. I can't remember the exact measurements, it was years ago,
but they were definately MUCH wider BW than the Jung regs.
The OP Z of my regs were in the order of 0.05ohms out to
1 mHz without any OP cap in place.
WRT to flatness, it is only an indication that the reg has
very wide BW and good settling time. If you look at opamps,
the ones with best settling time are always low open loop gain,
less internal stages and very fast.
Just as I readily accepted that YOU heard a difference when
reading about listening tests in AA. What makes you right and
me and others wrong? What makes your listening tests unbiased?
I tested my regs with some NON TECHNICAL listeners who didn't
even know what feedback was and observed their opinions,
totally free of placebo. So, whereas my judgement could have
been biased, they only wanted the best sound for their DAC...
and I gave them whichever iteration they preferred... often
my reaction was "why does this sound better". Often there
are more questions than answers. At least I am honest about it!
It seems you feel most people here use open loop + trannies
for I-V due to a lack of OPA implemetational knowledge, deluding
ourselves that we have made a sonic improvement? Do you
think we are so stupid? Do you not think that many of us
have tried the venerable AD811 and countless others with
countless power supply iterations and THEN decided to move
on to more fruitful ground from shear frustration.
You may find it interesting that one of the biggest innovators in
digital, Apogee Digital, used zero feedback discrete I-V on
the DA1000. This was the one repackaged by Mark
Levinson for Cello (same I-V). Wadia also has their own style of
ZFB I-V on their ultra expensive DACs.
Then there's Mr Edmund Meitner, know him.... he also seems to
be a proponent of ZFB DAC AND ADC interface on his incredibly
highly regarded and measuring converters.
Jan, I have a lot of respect for your work and read very
carefully all the articles on the super regs. They were very well
done, represented a huge amount of work and I learnt a lot from
them. I applaud your effort!
But could you please do some of us the favour of
acknowledgment of our existence... there are also some other
people here who have much to contribute
to this so very challenging of pursuits.
Terry
IV-converter
Hi Terry,
Still nocking around in these woods!
You made me very curious about the Apogee, Wadia or Meitner discrete IV-converter. Any idea what it is about? Something like Jocko's circuit?
I am using my discrete JFET circuit and agree with you that it is better, or should I say might be better, than AD811 or OPA603 current feedback amplifiers.😉
Hi Terry,
Still nocking around in these woods!
You made me very curious about the Apogee, Wadia or Meitner discrete IV-converter. Any idea what it is about? Something like Jocko's circuit?
I am using my discrete JFET circuit and agree with you that it is better, or should I say might be better, than AD811 or OPA603 current feedback amplifiers.😉
Re: WINE CHAIRS
The guy to the right is David Prowse, probably
better known as the actor who inhabitated Darth Vader's clothes in Star Wars.
And yes, Vader probably schlepped a life support power supply with him all time.
fdegrove said:
The guy to the right is David Prowse, probably
better known as the actor who inhabitated Darth Vader's clothes in Star Wars.
And yes, Vader probably schlepped a life support power supply with him all time.
Re: IV-converter
Hi Elso,
I believe Wadia uses a complementary circuit which is actually
fabricated for them by someone so it can be direct coupled
without DC offset problems. Maybe some kind of folded cascode.
Apogee was sealed in a chunk of resin... but was reportedly
FET based (mos or j ?). I know nothing of Meitner circuits only
that he hinted of this approach and it was confirmed by a
reviewer (T Jung) in a pro audio mag. He also felt that the
humble OPA was not the ultimate for this application.
Terry
Elso Kwak said:Hi Terry,
Still nocking around in these woods!
You made me very curious about the Apogee, Wadia or Meitner discrete IV-converter. Any idea what it is about? Something like Jocko's circuit?
I am using my discrete JFET circuit and agree with you that it is better, or should I say might be better, than AD811 or OPA603 current feedback amplifiers.😉
Hi Elso,
I believe Wadia uses a complementary circuit which is actually
fabricated for them by someone so it can be direct coupled
without DC offset problems. Maybe some kind of folded cascode.
Apogee was sealed in a chunk of resin... but was reportedly
FET based (mos or j ?). I know nothing of Meitner circuits only
that he hinted of this approach and it was confirmed by a
reviewer (T Jung) in a pro audio mag. He also felt that the
humble OPA was not the ultimate for this application.
Terry
Hi Elso,
Have you tried a mosfet in place of the triple and if so what were your results. I suppose you would loose a few volts and you would need a mosfet with a low Rds. Just curious.
Jam
Have you tried a mosfet in place of the triple and if so what were your results. I suppose you would loose a few volts and you would need a mosfet with a low Rds. Just curious.
Jam
Elso,
I believe that Wadia uses a circuit known as a current conveyor and it is manufactured for them as an IC. Many years ago there was an article about current conveyors in Wireless World I will have to try to look for it. Meridian might have used the same topology too.
Jam
I believe that Wadia uses a circuit known as a current conveyor and it is manufactured for them as an IC. Many years ago there was an article about current conveyors in Wireless World I will have to try to look for it. Meridian might have used the same topology too.
Jam
MOSFET
No I did not try a MOSFET. I felt a triple was just fine as I needed three Vbe drops or about 1.8V above the 5V output in order to use the LM329. Actually the output is 5.1V. I saw the triple at the Guido Tent and Heijligers website.
http://members.chello.nl/~m.heijligers/DAChtml/suplv.pdf
They copied it from Audionote DAC-3 who are using five transistors Darlington connected.😱
Hi jam,jam said:
No I did not try a MOSFET. I felt a triple was just fine as I needed three Vbe drops or about 1.8V above the 5V output in order to use the LM329. Actually the output is 5.1V. I saw the triple at the Guido Tent and Heijligers website.
http://members.chello.nl/~m.heijligers/DAChtml/suplv.pdf
They copied it from Audionote DAC-3 who are using five transistors Darlington connected.😱
Re: Re: Re: Re: Why etc
Well, terry, that's a hell of a long and involved post. Let me try to reply the best I can. If you don't mind, for brevity, I'll snip out the parts I am not commenting on:
But, that said, yeah, I think you are right overall. I have a tendency to be negative against unsubstantiated claims. Thank for pointing that out. Have a great Xmas and a fastantic 2003!
Jan Didden
"In order to be a true and rightfull member of a flock of sheep, one must, above all, be a sheep" - Albert Einstein.
Well, terry, that's a hell of a long and involved post. Let me try to reply the best I can. If you don't mind, for brevity, I'll snip out the parts I am not commenting on:
Terry Demol said:
But, that said, yeah, I think you are right overall. I have a tendency to be negative against unsubstantiated claims. Thank for pointing that out. Have a great Xmas and a fastantic 2003!
Jan Didden
"In order to be a true and rightfull member of a flock of sheep, one must, above all, be a sheep" - Albert Einstein.
Discreet regulators
There are many voltage regulators without op amps as error amps. I have seen several such circuits used in comercial products. The reasons for a discreet design vs. op amp based regulators are the same as for audio circuit blocks. There are many designers who feel that a flat impedance in the audio band is a sonic advantage. Impedances below a few 10s of milliohms can be swamped by wiring impedance so remote sensing is required if numbers this low are desired. Good transient response above at frequencies in the audio band is a very good idea for circuits like DACs with a lot of ultrasonic current demands.
The transistion from the regulators contribution to output impedance to frequencies were the capacitors output impedance dominates needs much more investigation.
I think there are many good reasons for discreet transistor regulator design. Like audio circuits, there are probably limits to the amount of negative feedback that can be applied the regulator circuits. I think that emphasis on PSRR is as important as output impedance and much work remains to be done in this area. Nested feedback loop design also could be used to a greater degree in regulator design than is at present.
The use of mosfets for the pass transistor will have about an order of magnitude disadvantage over bipolar transistors for open loop output impedance for currents below a few hundred milliamps due to Mosfets lower transconductance. There are many excellent bipolar transistors that look very good for the pass element which have not been used yet in published regulator designs. (hint: Zetex)
Erno Borbely has some interesting regulator designs.
http://www.audiokits.com/pics/EB_401_254-complete.pdf
http://www.audiokits.com/pics/All FET Lineamp-complete.pdf
There are many voltage regulators without op amps as error amps. I have seen several such circuits used in comercial products. The reasons for a discreet design vs. op amp based regulators are the same as for audio circuit blocks. There are many designers who feel that a flat impedance in the audio band is a sonic advantage. Impedances below a few 10s of milliohms can be swamped by wiring impedance so remote sensing is required if numbers this low are desired. Good transient response above at frequencies in the audio band is a very good idea for circuits like DACs with a lot of ultrasonic current demands.
The transistion from the regulators contribution to output impedance to frequencies were the capacitors output impedance dominates needs much more investigation.
I think there are many good reasons for discreet transistor regulator design. Like audio circuits, there are probably limits to the amount of negative feedback that can be applied the regulator circuits. I think that emphasis on PSRR is as important as output impedance and much work remains to be done in this area. Nested feedback loop design also could be used to a greater degree in regulator design than is at present.
The use of mosfets for the pass transistor will have about an order of magnitude disadvantage over bipolar transistors for open loop output impedance for currents below a few hundred milliamps due to Mosfets lower transconductance. There are many excellent bipolar transistors that look very good for the pass element which have not been used yet in published regulator designs. (hint: Zetex)
Erno Borbely has some interesting regulator designs.
http://www.audiokits.com/pics/EB_401_254-complete.pdf
http://www.audiokits.com/pics/All FET Lineamp-complete.pdf
Discrete Power Supply
Hi Fred,
Thanks for the link to Erno Borbely. In your post you state that a MOSFET passtransistor is inferior to a bipolar trasistor but Erno is using MOSFET's. Do you suggest to use Zetex low saturation/ high gain transistors in this position?
Metaxas Audio has a simple regulator on there website. He even does not use a voltage amplification stage only a current mirror.
http://www.metaxas.com/pages/masnewfiles/index.html
(Go to do it yourself, then click on SP-3 preamplifier. The powersupply schematic is at the end of the page). Time has not permitted me to build it yet. 😉
Hi Fred,
Thanks for the link to Erno Borbely. In your post you state that a MOSFET passtransistor is inferior to a bipolar trasistor but Erno is using MOSFET's. Do you suggest to use Zetex low saturation/ high gain transistors in this position?
Metaxas Audio has a simple regulator on there website. He even does not use a voltage amplification stage only a current mirror.
http://www.metaxas.com/pages/masnewfiles/index.html
(Go to do it yourself, then click on SP-3 preamplifier. The powersupply schematic is at the end of the page). Time has not permitted me to build it yet. 😉
Re: Further Improved Poer supply
Elso, you could swap D1 and C3 and put a resistor in between to filter the noise from the voltage reference.
Elso, you could swap D1 and C3 and put a resistor in between to filter the noise from the voltage reference.
Elso Kwak said:
Re: Re: Re: Further Improved Power supply
Elso,
It may not be critical for the circuit you have designed but from a point of elegance, the addition of a resistor and swapping D1 and C3 could significantly reduce the 75nV/sq.root-Hz reference noise.
I mean you have got the capacitors there in the first place, why brute force filter the reference when you can add a litle more finesse with a resistor and be more gentle to your reference.
As I said, low noise may not be your ultimate goal but it is there for the taking and may be beneficial for other designs.
Regards, Craig.
Elso,
It may not be critical for the circuit you have designed but from a point of elegance, the addition of a resistor and swapping D1 and C3 could significantly reduce the 75nV/sq.root-Hz reference noise.
I mean you have got the capacitors there in the first place, why brute force filter the reference when you can add a litle more finesse with a resistor and be more gentle to your reference.
As I said, low noise may not be your ultimate goal but it is there for the taking and may be beneficial for other designs.
Regards, Craig.
Elso Kwak said:
Re: Re: Re: Re: Why etc
Hi Terry,
Were they my Audio Amateurs that I had in your library? Interesting articles when I first read them in 90,91,92. When did you read them 95,96?
That discrete reg low open loop gain reg you built? Wasn't that the one based on my original shunt arangement which I said wouldn't sound as good but would measure better? It was the CFB or Silaki pair wasn't it.
Any how we both found my original shunt was the better one hey.
I share your frustration sometimes when I read these groups but hey we have been there and done that.
You said it was a very steep learning curve for you when we first colaborated but I find you are giving Jan more recognition than myself. Who was it that did the AD811 regs? Who did not know about capcitors when I first met them?
Can I have some recognition too please?
Thanks, Craig.
BTW, is that mountain bike ride still on ;-)
Hi Terry,
Were they my Audio Amateurs that I had in your library? Interesting articles when I first read them in 90,91,92. When did you read them 95,96?
That discrete reg low open loop gain reg you built? Wasn't that the one based on my original shunt arangement which I said wouldn't sound as good but would measure better? It was the CFB or Silaki pair wasn't it.
Any how we both found my original shunt was the better one hey.
I share your frustration sometimes when I read these groups but hey we have been there and done that.
You said it was a very steep learning curve for you when we first colaborated but I find you are giving Jan more recognition than myself. Who was it that did the AD811 regs? Who did not know about capcitors when I first met them?
Can I have some recognition too please?
Thanks, Craig.
BTW, is that mountain bike ride still on ;-)
😉Terry Demol said:
Re: Re: Re: Re: Re: Why etc
Well I'll give you recognition for political/diplomatic incorrectness!
You sound like my 6 YO son.
Look, let's take this off forum and do everyone here a big
favour. The idea is to keep personal attacks/details low and
information up.
MTB rides are always on! But you'll have to a) wait till
I finish building a 2nd bike or b) buy one for yourself.
Either way, after this post, don't expect an easy one.
Terry
CraigBuckingham said:
Well I'll give you recognition for political/diplomatic incorrectness!
You sound like my 6 YO son.
Look, let's take this off forum and do everyone here a big
favour. The idea is to keep personal attacks/details low and
information up.
MTB rides are always on! But you'll have to a) wait till
I finish building a 2nd bike or b) buy one for yourself.
Either way, after this post, don't expect an easy one.
Terry
Re: Printed out the 7 points and taped them on the wall
jean-paul,
I agree with your assessment of the Sanyo Oscon for analog.
I can't stand the things but I have friends that swear by them. I cannot believe they like them as we almost always agree on all our other observations.
Call me disillusioned. 😕
Craig.
jean-paul said:
jean-paul,
I agree with your assessment of the Sanyo Oscon for analog.
I can't stand the things but I have friends that swear by them. I cannot believe they like them as we almost always agree on all our other observations.
Call me disillusioned. 😕
Craig.
long time no post ...
thanks for all the help, I was busy and unable to post my final findings untill now.
I have gone back to the 7805, apperently (enlightened by T), in a digital design, it is better to filter out all the high freq noise (using caps and inductors) instead of trying to regulatred them using a ultra fast wide band width regulator.
However, even after extensive mod, my Rotel 991 is still not as good as my old Arcam Alpha 5 (TDA1541A) in NOS mode. Also I have made a sin(x)/x compensation filter which improve the sound of the NOS TDA1541A quite a bit. Details in the Sin(x)/x post.
thanks for all the help, I was busy and unable to post my final findings untill now.
I have gone back to the 7805, apperently (enlightened by T), in a digital design, it is better to filter out all the high freq noise (using caps and inductors) instead of trying to regulatred them using a ultra fast wide band width regulator.
However, even after extensive mod, my Rotel 991 is still not as good as my old Arcam Alpha 5 (TDA1541A) in NOS mode. Also I have made a sin(x)/x compensation filter which improve the sound of the NOS TDA1541A quite a bit. Details in the Sin(x)/x post.
Re: Improved (?) Circuit Correction of Drawing Error
I just got a email pointing me at a stupid drawing error. As the shaded part of the electrolytics is the minus side these have to be connected to ground of course.
I apologise.
Attached (hopefully) the corrected schematic.
Hi,Elso Kwak said:
I just got a email pointing me at a stupid drawing error. As the shaded part of the electrolytics is the minus side these have to be connected to ground of course.
I apologise.
Attached (hopefully) the corrected schematic.
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