So what would be the ideal large power supply capacitors?
Is it always better if ESR and ESL are low? (assuming all other variables held constant)
Is it always better if ESR and ESL are low? (assuming all other variables held constant)
No........
The worst sounding amp that I ever made had a bank of low ESR, low ESL swithcmode caps.
Think about how the transformer will act at the peak of the charging cycle. And how much more crud it could let through if it isn't happy during those few milliseconds.
Of course, whether it is toroid or stacked lamination, small vs large, also has an role in the mystery.
(For the person that I 'splained this to last week, and wasn't happy with my answer: tough. Same answer this week. Hope that the rest find it thought provoking. Too bad he didn't.)
Jocko
The worst sounding amp that I ever made had a bank of low ESR, low ESL swithcmode caps.
Think about how the transformer will act at the peak of the charging cycle. And how much more crud it could let through if it isn't happy during those few milliseconds.
Of course, whether it is toroid or stacked lamination, small vs large, also has an role in the mystery.
(For the person that I 'splained this to last week, and wasn't happy with my answer: tough. Same answer this week. Hope that the rest find it thought provoking. Too bad he didn't.)
Jocko
That's probably a reason some of us only use choke-input supplies. A bit tricky in a SS power amp though 🙂
Joseph K said:
Post 209, did you get the right picture Joseph? I think it's the same as post 207
Look at the numbers above the diagram, and you'll see it's not the same picture, just very similar.
Rune
Rune
Power Supply
A PI-filter is doable!
And if I take Jocko's nice hint into consideration the first caps after the transformer should be stinking normal and the caps after the choke low ESR. What am I waiting for; the Panasonic FC's are staring at me.........
Hi analog_sa,analog_sa said:
A PI-filter is doable!
And if I take Jocko's nice hint into consideration the first caps after the transformer should be stinking normal and the caps after the choke low ESR. What am I waiting for; the Panasonic FC's are staring at me.........
Yes, I see now the difference and it is _small_ virtual zero! So what conclusion do we make of this? The resistor placement doesn't matter?runebivrin said:
Carlos' idea maybe holds?
Tha PSU sindroma
This PSU is the best thing for those who tried it and the biggest headache for those who refuse to try it.😎
I thought you had scrutinized this by now.
peranders said:
This PSU is the best thing for those who tried it and the biggest headache for those who refuse to try it.😎
I thought you had scrutinized this by now.
I think Joseph has shown us very good examples of this with statical measurements but I'm not totally convinced how much influence this have on a 100 kHz amp in the region of 1 MHz for audio signals less than 13kHz (most of the energy).
I think Janneman has a good point when he is talking about blind tests. Still Carlos, I don't deny anything. I'm just being skeptical. Compare the debate of peeling caps jackets off. Do you believe in the that? In this snubber case we can clearly measure a difference, that's something!
I think Janneman has a good point when he is talking about blind tests. Still Carlos, I don't deny anything. I'm just being skeptical. Compare the debate of peeling caps jackets off. Do you believe in the that? In this snubber case we can clearly measure a difference, that's something!
Konnichiwa,
Actually, I do not "Believe in the that". I don't have to believe, I happen to know.
Do a blind test, but use a testsubject willing to hear differences if they exist but without any particular emotional or moral investment. Oh yes, also please use well designed speakers and other equipment and make sure your test is sensitive to small differences (eg minimum absoloute polarity reversal reliably detected and ideally also differences between generic interconnects and RG-214 with WBT locking plugs detetctable). Then you know too.
Sayonara
peranders said:
Actually, I do not "Believe in the that". I don't have to believe, I happen to know.
Do a blind test, but use a testsubject willing to hear differences if they exist but without any particular emotional or moral investment. Oh yes, also please use well designed speakers and other equipment and make sure your test is sensitive to small differences (eg minimum absoloute polarity reversal reliably detected and ideally also differences between generic interconnects and RG-214 with WBT locking plugs detetctable). Then you know too.
Sayonara
peranders said:
I don't.
An experienced listener has the same results with blind or sighted tests.
Who may think otherwise doesn't have experience with either, or lets himself be fooled by statistics of other listeners' conclusions, or has been reading too many audio magazines.
Thorsten, it's a good feeling to be knowing!Kuei Yang Wang said:
Not everybody are so fortunate.
Konnichiwa,
I do also know that "knowing" has little to do with being fortunate. It usually comes from empirical evaluation of a given thesis. In other words, it comes from actual work, instead of from lazily arguing about why black is really white.
Sayonara
peranders said:Thorsten, it's a good feeling to be knowing!
I do also know that "knowing" has little to do with being fortunate. It usually comes from empirical evaluation of a given thesis. In other words, it comes from actual work, instead of from lazily arguing about why black is really white.
Sayonara
Hi all!
Jorge, what kind of 100nF film cap is that you have with 1.5 ohm ESR?
What I have seen up to now is that those have an ESR <= .05 ohm!
Properly this is the problem with them, when bypassing!
So why don't we all just put that, lets say, .3 ohm in series with them?
Peranders, as with regards bandwith of the amplifier & and the bandwith of the signal applied - they are two different things!
Anyway, I played with LM3875 dated back at 1997, here at job. I was using it as an amplifier driving some big coils, which actually presented
a light load for it - so it was joyfully driving that coil up two 2 MHz!
100 kHz is only its power bandwith, limited by its slew rate.
But this would not stop it to have nice small signal Rf oscillations.
I would like to quote you national - gain bandwith typical is 8 MHz!!
Then it's true that you have 13kHz audio bandwith, even that one with a strong attenuation in the power spectrum for the high frequencies. That is, only until you drive it into clipping, which will happen with me every time, having at disposal only some watts!
Then bingo! you have a power spectrum extending much above 100 kHz!
Then, you filter the signal on the input, and feel safe. Well, how about the other three inputs of that same amplifier? Did you filter well, against RF, with that ringing bypass structure on the power pins? Don't forget about that nice EMI receiver antenna loop installed, called power supply! Did you filter well against the RF creeping in from the output? Don't forget about that nice EMI receiver antenna loop on it, called loudspeaker...
So, what I would like to emphasise again - this is NOT a tube amplifier! It is, by intention, an AM radio receiver, it's only us that are trying to put it to an illegal use...
Jorge, what kind of 100nF film cap is that you have with 1.5 ohm ESR?
What I have seen up to now is that those have an ESR <= .05 ohm!
Properly this is the problem with them, when bypassing!
So why don't we all just put that, lets say, .3 ohm in series with them?
Peranders, as with regards bandwith of the amplifier & and the bandwith of the signal applied - they are two different things!
Anyway, I played with LM3875 dated back at 1997, here at job. I was using it as an amplifier driving some big coils, which actually presented
a light load for it - so it was joyfully driving that coil up two 2 MHz!
100 kHz is only its power bandwith, limited by its slew rate.
But this would not stop it to have nice small signal Rf oscillations.
I would like to quote you national - gain bandwith typical is 8 MHz!!
Then it's true that you have 13kHz audio bandwith, even that one with a strong attenuation in the power spectrum for the high frequencies. That is, only until you drive it into clipping, which will happen with me every time, having at disposal only some watts!
Then bingo! you have a power spectrum extending much above 100 kHz!
Then, you filter the signal on the input, and feel safe. Well, how about the other three inputs of that same amplifier? Did you filter well, against RF, with that ringing bypass structure on the power pins? Don't forget about that nice EMI receiver antenna loop installed, called power supply! Did you filter well against the RF creeping in from the output? Don't forget about that nice EMI receiver antenna loop on it, called loudspeaker...
So, what I would like to emphasise again - this is NOT a tube amplifier! It is, by intention, an AM radio receiver, it's only us that are trying to put it to an illegal use...
Thorsten does the work, I listen.
Lazyness is a strong word. How many around here actually do the work and how many listen?
Anyway, it has been an interesting debate and not as trivial as why black is black.
Joseph has shown us good measurements (done the work!) and we have had put a spotlight on the problem. Not yet haven't anybody picked in a blind test if it's possible to record any difference between a conventional PS and a snubberized PS (at least I created a new word, it took some work for it!). I haven't got any time nor the opportunity for a blind test but I sure will have this snubber in mind.
If you remember right we had a debate about Zobel or not and output inductor or not. The results of this weren't to obvious. What do you say Thorsten about those issues? have you got it or are you those who don't get?
The thread has caught many people's interest if you check "views" and I wonder what all these silent readers think.
I'll guess this issue had general interest and can take to be discussed without hard feelings.
Lazyness is a strong word. How many around here actually do the work and how many listen?
Anyway, it has been an interesting debate and not as trivial as why black is black.
Joseph has shown us good measurements (done the work!) and we have had put a spotlight on the problem. Not yet haven't anybody picked in a blind test if it's possible to record any difference between a conventional PS and a snubberized PS (at least I created a new word, it took some work for it!). I haven't got any time nor the opportunity for a blind test but I sure will have this snubber in mind.
If you remember right we had a debate about Zobel or not and output inductor or not. The results of this weren't to obvious. What do you say Thorsten about those issues? have you got it or are you those who don't get?
The thread has caught many people's interest if you check "views" and I wonder what all these silent readers think.
I'll guess this issue had general interest and can take to be discussed without hard feelings.
This was only food for thought. I know there are complex relationships between the parameters I mentioned and not easy to examine.Joseph K said:
peranders said:
But that's what you are.
You ask others to do the job for you.
You even have your GC amps where you can try the snubber, listen, measure, report.
I can't figure out how trying a couple of resistors and caps can take longer than reading this thread.
peranders said:
P-A,
one of those 'silent readers' does think that you make a fool out of yourself
when you constantly refuse to make your own empirical judgements 🙄
Apart from that, this thread is highly educating, even for a non-technician like me.
Joseph K must be the most welcome and valuable newcomer in this forum for ages.
A very warm welcome from me!
Konnichiwa,
Zobels and Output inductors are essential if you want to build an amplifier with loop feedback that is stable regardless of load. Sadly they usually FUBAR the sound so one needs to seek the happy compromise the keeps 'scope, amp and ears happy.
In DIY we can do such things conciously and deviate from the "average industry standard" as we understand the issues involved and can deal with them.
Now if I was to design a commercial Amp, it would have a an Output Inductor and carefully designed and applied zobel circuits to keep the compromise of widest possible bandwidth, stability with reactive loads and a non-reactive behaviour of the output network (Actually, I have been doing something along those lines only very recently). That way, if some idiot wants to use super high capacitance speaker cables the Amp remains stable.
Now if I was to build an Amp for myself I'd prefer to follow the Naim and Dennis Morecroft route of not using such output circuitry and using a modest value series resistor and keep the rest of the inductance needed in the speakercable, as it actually quite reliably sounds better.
And that is what at least to me DIY Audio is all about, the ability to step outside the classic convention of how a given product has to be designed in order to "fit into the market". If you apply the same industrial methodes and approaches and implement the same compromises designers of commercial gear do you have missed the point.
If one uses ones spare time to actually earn money instead of tinkering with DIY Gear one will quickly have the money for very good commercial gear that will be as good as the DIY version of it. DIY is there to to shake off the shackles of the Market and it's dictates, not to blissfully embrace them in an illguided attempt to save a few bucks.
Sayonara
peranders said:
Zobels and Output inductors are essential if you want to build an amplifier with loop feedback that is stable regardless of load. Sadly they usually FUBAR the sound so one needs to seek the happy compromise the keeps 'scope, amp and ears happy.
In DIY we can do such things conciously and deviate from the "average industry standard" as we understand the issues involved and can deal with them.
Now if I was to design a commercial Amp, it would have a an Output Inductor and carefully designed and applied zobel circuits to keep the compromise of widest possible bandwidth, stability with reactive loads and a non-reactive behaviour of the output network (Actually, I have been doing something along those lines only very recently). That way, if some idiot wants to use super high capacitance speaker cables the Amp remains stable.
Now if I was to build an Amp for myself I'd prefer to follow the Naim and Dennis Morecroft route of not using such output circuitry and using a modest value series resistor and keep the rest of the inductance needed in the speakercable, as it actually quite reliably sounds better.
And that is what at least to me DIY Audio is all about, the ability to step outside the classic convention of how a given product has to be designed in order to "fit into the market". If you apply the same industrial methodes and approaches and implement the same compromises designers of commercial gear do you have missed the point.
If one uses ones spare time to actually earn money instead of tinkering with DIY Gear one will quickly have the money for very good commercial gear that will be as good as the DIY version of it. DIY is there to to shake off the shackles of the Market and it's dictates, not to blissfully embrace them in an illguided attempt to save a few bucks.
Sayonara
- Status
- Not open for further replies.