Thunderstone:
>I find most 78XX/79XX (in fact all I tried) to sound very similar with a few 1,000uF after the Reg.<
I have conducted blind listening tests on 78xx/79xx regulators from various manufacturers, and in the test circuit applications, the regulators were frequently followed by a fair amount of capacitance. My experiments suggest that the statement quoted above may not necessarily be true for all circuit applications.
regards, jonathan carr
>I find most 78XX/79XX (in fact all I tried) to sound very similar with a few 1,000uF after the Reg.<
I have conducted blind listening tests on 78xx/79xx regulators from various manufacturers, and in the test circuit applications, the regulators were frequently followed by a fair amount of capacitance. My experiments suggest that the statement quoted above may not necessarily be true for all circuit applications.
regards, jonathan carr
Re: Re: Re: Re: Re: The answer maybe 42
Yes, if you were reviewing loudspeakers 25 years ago. [/B][/QUOTE]
Haha, speakers are still the same KHorns......
-----------------------------------------------fmak said:[BTW I have very short hair now but very long hair 25 years ago. Does it really matter?
Yes, if you were reviewing loudspeakers 25 years ago. [/B][/QUOTE]
Haha, speakers are still the same KHorns......
Andy:
>Topology is almost irrelevant, but PSU's bring big benefits to everything I've tried.<
Overall, I agree that putting more effort into the power supply usually yields subjective sonic benefits. Nonetheless, my findings so far suggest that circuit designs in which the total load current drawn from the power supply is constant - super shunt regulation, folded-cascode amplification etc. - the sonic effect of the PS filter capacitors is substantially reduced, and the sonic effect of the transformer is also reduced (albeit to a noticeably lesser degree).
hth, jonathan carr
>Topology is almost irrelevant, but PSU's bring big benefits to everything I've tried.<
Overall, I agree that putting more effort into the power supply usually yields subjective sonic benefits. Nonetheless, my findings so far suggest that circuit designs in which the total load current drawn from the power supply is constant - super shunt regulation, folded-cascode amplification etc. - the sonic effect of the PS filter capacitors is substantially reduced, and the sonic effect of the transformer is also reduced (albeit to a noticeably lesser degree).
hth, jonathan carr
Re: Blame where blame is due.
Ooops, I was too overcome by the outpouring of information to give proper credit.
As for adding caps everywhere, did I mention I like to design boards to be small, diy or not, even if they are "only" low-tech linear supplies?
Sorry for the stupid question, but my experience is more in digital design, and not audio and DAC. And yes, my boards often use a decoupling cap on the digital supply, sometimes even more than one per board
(I will now go and rearrange my drawer of old neglected 78xx and 79xx parts in new and more esthetically pleasing patterns...)
Ooops, I was too overcome by the outpouring of information to give proper credit.
As for adding caps everywhere, did I mention I like to design boards to be small, diy or not, even if they are "only" low-tech linear supplies?
Sorry for the stupid question, but my experience is more in digital design, and not audio and DAC. And yes, my boards often use a decoupling cap on the digital supply, sometimes even more than one per board
(I will now go and rearrange my drawer of old neglected 78xx and 79xx parts in new and more esthetically pleasing patterns...)
Re: Carr elected three terms
About the size/type of supply I had in mind, yes.
One more try:
But what were the performance goals, or requirements? I have seen lots of simple linear supply designs, many with little or no protection against RF or digital noise getting into the analog supply.
Of course, noise from any of my digital designs is only "good noise", and anyway I usually deny all knowledge of its existence if any happens to be captured on a scope...
Besides, the real world is all digital now, right?
About the size/type of supply I had in mind, yes.
One more try:
But what were the performance goals, or requirements? I have seen lots of simple linear supply designs, many with little or no protection against RF or digital noise getting into the analog supply.
Of course, noise from any of my digital designs is only "good noise", and anyway I usually deny all knowledge of its existence if any happens to be captured on a scope...
Besides, the real world is all digital now, right?
Dear Fred:
The power supply of the prototype unit in the photo that you posted consists of R-core transformers with dual secondaries, dual-bridge rectification, industrial-grade filter capacitors, and low-dropout adjustable regulators, with composite electrolytic and stacked-film bypasses at every load. But I did put a reasonable amount of effort into the board layout and harness design, and I can state with a reasonable degree of confidence that much of the sonic performance can be credited to this, rather than the components or topology (neither of which I consider particularly remarkable).
BTW Fred, I appreciate the masking gesture, but I already took the liberty of placing the really fun stuff _underneath_ the board, where it would be hidden from view.
OTOH, for the production version, I am either going to put in a super-shunt regulation scheme, or a linear pre-reg and shunt reg combo. Yes, there has been the occasional daft discrete regulator or two (or 48), but not this time.
I will probably also incorporate a variant of the following flyingcap circuit (Fred and Andy are both familiar with this one), although if previous experiences are anything to go by, I may want to multiply the total amount of capacitance that goes into the power supply by a factor of two or three over what I would normally use.
http://www.diyaudio.com/forums/showthread.php?postid=151191#post151191
best, jonathan carr
The power supply of the prototype unit in the photo that you posted consists of R-core transformers with dual secondaries, dual-bridge rectification, industrial-grade filter capacitors, and low-dropout adjustable regulators, with composite electrolytic and stacked-film bypasses at every load. But I did put a reasonable amount of effort into the board layout and harness design, and I can state with a reasonable degree of confidence that much of the sonic performance can be credited to this, rather than the components or topology (neither of which I consider particularly remarkable).
BTW Fred, I appreciate the masking gesture, but I already took the liberty of placing the really fun stuff _underneath_ the board, where it would be hidden from view.
OTOH, for the production version, I am either going to put in a super-shunt regulation scheme, or a linear pre-reg and shunt reg combo. Yes, there has been the occasional daft discrete regulator or two (or 48), but not this time
.I will probably also incorporate a variant of the following flyingcap circuit (Fred and Andy are both familiar with this one), although if previous experiences are anything to go by, I may want to multiply the total amount of capacitance that goes into the power supply by a factor of two or three over what I would normally use.
http://www.diyaudio.com/forums/showthread.php?postid=151191#post151191
best, jonathan carr
Easy peasy lemon-squeezy
Jonathan,
I'm sure I'd agree on all counts (I will build those circuits at some point!), but it is fair to point out that Super Shunt Regulation probably qualifies as a good PSU, rather than an amp circuit topology
My suggestion to those that found the Jung-reg's not beneficial (in analogue circuits) were not using ideal implementations, or had other masking effects, if they found 3-terminal alternatives better.
Elso,
Don't ever take my posts as a put down of other methods, like you, what I hear is all - more than ever I find good engineering a pre-requisite to good performance, but almost NEVER a guarantee. Your ears are the best tool, but it must be understood that when dealing with PSU's that are at these levels of engineering, the design as a whole (not just the circuit diagram) is critical. The circuit diagram tells little about a circuit performance in practice.
Actually I disagree with this.
The band edges do not define musical performance, neither does tonal accuracy or frequency response.
Think about how much you can tell about the emotional state of someone on a telephone - limited bandwidth and dynamic range.
Some hi-fi totally misses this emotional element.
When you go to a live performance, particularly non-classical, the sound quality, in hi-fi terms is rarely great, but it often makes you dance, tap your feet, sing, cry etc...
There are assessment methods that home in on the primary aspects of music, and they work and provide long-term musical satisfaction if you're prepared to let them.
There's always an element of subjectivity, but I don't believe that has anything to do with the fundamental musical message.
Cue another blind listening test thread
Andy.
Jonathan,
I'm sure I'd agree on all counts (I will build those circuits at some point!), but it is fair to point out that Super Shunt Regulation probably qualifies as a good PSU, rather than an amp circuit topology
My suggestion to those that found the Jung-reg's not beneficial (in analogue circuits) were not using ideal implementations, or had other masking effects, if they found 3-terminal alternatives better.
Elso,
Don't ever take my posts as a put down of other methods, like you, what I hear is all - more than ever I find good engineering a pre-requisite to good performance, but almost NEVER a guarantee. Your ears are the best tool, but it must be understood that when dealing with PSU's that are at these levels of engineering, the design as a whole (not just the circuit diagram) is critical. The circuit diagram tells little about a circuit performance in practice.
Actually I disagree with this.
The band edges do not define musical performance, neither does tonal accuracy or frequency response.
Think about how much you can tell about the emotional state of someone on a telephone - limited bandwidth and dynamic range.
Some hi-fi totally misses this emotional element.
When you go to a live performance, particularly non-classical, the sound quality, in hi-fi terms is rarely great, but it often makes you dance, tap your feet, sing, cry etc...
There are assessment methods that home in on the primary aspects of music, and they work and provide long-term musical satisfaction if you're prepared to let them.
There's always an element of subjectivity, but I don't believe that has anything to do with the fundamental musical message.
Cue another blind listening test thread
Andy.
Most of them
"I already took the liberty of placing the really fun stuff _underneath_ the board"
Well maybe not all the fun....... I cropped what might have been a **d* ****a* out the the photo and bet there a could few more ****a*s hiding on the bottom of the PCB. Those sound very good in that circuit location and is one of the most important places to use **d* ****a* if you are going to use **d* ****a*s. Of course I could be completely mistaken, like I was about the 48 volt relay......
John Drake
"I already took the liberty of placing the really fun stuff _underneath_ the board"
Well maybe not all the fun....... I cropped what might have been a **d* ****a* out the the photo and bet there a could few more ****a*s hiding on the bottom of the PCB. Those sound very good in that circuit location and is one of the most important places to use **d* ****a* if you are going to use **d* ****a*s. Of course I could be completely mistaken, like I was about the 48 volt relay......
John Drake
Attachments
Re: Easy peasy lemon-squeezy
I realise my way of working is totally different from most engineers.
I try to gauge my ears regulary on a life concert but NOT pop!!! Sorry I get sick and almost have to vomit after a hour at these extreme high listening levels and distortion. It is the most severe punishment you can think of for me.
I never experienced that the "right" PCB layout has a profound influence on the sound. I usually make boards Jim Williams of Linear Technolgy style before making a final layout.
But I try to avoid stupid mistakes. If the supply oscillates I clearly did something wrong.
It is my opinion the powersupply is part of the active circuit and has influence on the sound just as the actual amplifier schematic.
Next Saterday I will visit clavicord and harpsichord concerts accompanied by appetizing morsels!.
Hi Andy..ALW said:
Elso,
Don't ever take my posts as a put down of other methods, like you, what I hear is all - more than ever I find good engineering a pre-requisite to good performance, but almost NEVER a guarantee. Your ears are the best tool, but it must be understood that when dealing with PSU's that are at these levels of engineering, the design as a whole (not just the circuit diagram) is critical. The circuit diagram tells little about a circuit performance in practice.
Actually I disagree with this.
The band edges do not define musical performance, neither does tonal accuracy or frequency response.
Think about how much you can tell about the emotional state of someone on a telephone - limited bandwidth and dynamic range.
Some hi-fi totally misses this emotional element.
When you go to a live performance, particularly non-classical, the sound quality, in hi-fi terms is rarely great, but it often makes you dance, tap your feet, sing, cry etc...
There are assessment methods that home in on the primary aspects of music, and they work and provide long-term musical satisfaction if you're prepared to let them.
There's always an element of subjectivity, but I don't believe that has anything to do with the fundamental musical message.
Cue another blind listening test thread
Andy.
I realise my way of working is totally different from most engineers.
I try to gauge my ears regulary on a life concert but NOT pop!!! Sorry I get sick and almost have to vomit after a hour at these extreme high listening levels and distortion. It is the most severe punishment you can think of for me.
I never experienced that the "right" PCB layout has a profound influence on the sound. I usually make boards Jim Williams of Linear Technolgy style before making a final layout.
But I try to avoid stupid mistakes. If the supply oscillates I clearly did something wrong.
It is my opinion the powersupply is part of the active circuit and has influence on the sound just as the actual amplifier schematic.
Next Saterday I will visit clavicord and harpsichord concerts accompanied by appetizing morsels!.
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