Frank, in all our scientific talking and analyzing we were so preoccupied that we forgot to check our sources.
It's not a philosophy, it's just a simple equilibrium.
Many audio websites from the Internet shouldn't even exist. ..Or they should change the word "audio" by "sound reproduction". ...And definitely not introducing the word "best".
Also, private audio clubs shouldn't be open to the general young public; they have nothing beneficial to teach. ...They have their own orgasmic and snobbish attitudes; very bad for our young generation and a better world.
It's a constant fight for my system is bigger than yours and fully analog, or digital, or both with the looks to go with it.
The music if not the same from the last sixty years or so, with new remasterings, pressings, higher resolution, new tape particles, new jitter reduction, new 200gr x 4 times the number of one single recording (45rpm), new jack-up prices in the $300-$2,000 range for a single LP, ...then it's Pop/Electronica music with an edge on the extremely irritating. No wonder audiophiles are always fighting between themselves!
Also, it is always "me", "my way of doing things", "my system", "that's what I do", "I'm using the electrons and protons from the snakes in my garden", blah-blah-blah me me me!
Also, we become accustomed to a place or few where we can have fun without being disturbed; a place of open discussions with an emphasis on good humor. ...And a dose of traditional electronics build, more or less conventional, plus new technologies that make more or less sense.
Also, we forgot where we came from and where we're going. ...Or we simply don't care and it's a free-for-all "me" type of short life on this planet.
I think that we owe ourselves to be better at evolving the right way; but in all this discordance we disconnect ourselves more and more from ourselves.
Mea culpa as equally.
It's not a philosophy, it's just a simple equilibrium.
Many audio websites from the Internet shouldn't even exist. ..Or they should change the word "audio" by "sound reproduction". ...And definitely not introducing the word "best".
Also, private audio clubs shouldn't be open to the general young public; they have nothing beneficial to teach. ...They have their own orgasmic and snobbish attitudes; very bad for our young generation and a better world.
It's a constant fight for my system is bigger than yours and fully analog, or digital, or both with the looks to go with it.
The music if not the same from the last sixty years or so, with new remasterings, pressings, higher resolution, new tape particles, new jitter reduction, new 200gr x 4 times the number of one single recording (45rpm), new jack-up prices in the $300-$2,000 range for a single LP, ...then it's Pop/Electronica music with an edge on the extremely irritating. No wonder audiophiles are always fighting between themselves!
Also, it is always "me", "my way of doing things", "my system", "that's what I do", "I'm using the electrons and protons from the snakes in my garden", blah-blah-blah me me me!
Also, we become accustomed to a place or few where we can have fun without being disturbed; a place of open discussions with an emphasis on good humor. ...And a dose of traditional electronics build, more or less conventional, plus new technologies that make more or less sense.
Also, we forgot where we came from and where we're going. ...Or we simply don't care and it's a free-for-all "me" type of short life on this planet.
I think that we owe ourselves to be better at evolving the right way; but in all this discordance we disconnect ourselves more and more from ourselves.
Mea culpa as equally.
USB 1 was 100 mA, USB 2 is 500 mA. The sources can usually provide twice that before shutting down. USB 3 etc. gets more complicated. Here is the latest: USB.org - USB Power Delivery It really does say 100W from USB!!
USB voltage can go from 4.5V to 5.5V.
What do you want to do with USB?
LF distrotion may increase, but my instruments and ears do not reigister the difference. Remember, I load the VAS with fixed value rsistors, which are reasonably linear from top to bottom, although I may add parallel cpas to those rsitors, to reduce high frequency gain and improve stabiity.
I do NOT believe there is any audible difference between an amp rated at 0.05% and 0.005% which is directly attributable to THD values. Therefore, it means nothing to me whether by LF gain is reduced, I don't want it to be too large anyway, I want it to be just enough for my purposes, say 26 dB closed loop and say 46 dB open loop.
In terms of the damping factor, remember, I use a Locanthi type triple output stage, which has a naturally lower output impedance, I use multiple output pairs whch also reduce output impedance, and large transformers with paralleled capacitors, which all help reduce output impedace. Lastly, I use paralleled output protection relays, again halving that part of the output impedance.
There are many roads all leading to Rome.
I agree. So the wider open loop bandwidth does little or no audible harm. That is not the same thing as saying that it does some good. I suppose it could be argued that increased LF distortion does some good if it better masks the unchanged HF distortion, but I'm not sure the ear/brain works like that.dvv said:
Over the years, as you can imagine, I have heard a very fair number of amplifiers. Statistically speaking, those with lower global NFB sounded better on average than those with high global NFB. They tended to be more open, more forthcoming, although of course there were significant differences among them.
This by no means clims that higher global NFB amps cannot sound good - I have also heard several of them which did sound very good indeed.
Perhaps this will surprise you, but those I liked least were amps with no global NFB at all. Somehow, they always sounded not quite finished, a little loose, as if they had not quite come together. Densen comes to mind, but there were others as well.
Put it all together and in effect I believe in a specific overall balance. Global NFB is a good thing if it is used judiciously, specifically if it is used to improve an already good circuit. It is bad if it is used as a cure-all, cure-all doesn't really exist because there's always a price ot pay for any extreme approach.
As for specific topologies, I am not aware of any statical rule, even a loose one. Any topology can sound one way or another. About the only concession I make is that fully complementary designs at least practically guarantee output symmetry, unless one has made some serious mistakes along the way, but then it's not the topology, it's the designer.
Lastly, my view is that sound quality is not connected to available power output in any direct way except the obvious, how much power does one need for one's speakers to come alive. Otala & Lohstroh, a nominally 25/50W into 8/4 Ohms taught me that, and it also taught me the importance of low impedance drive capability. I don't mean Wayne, he's off the charts, but one cannot deny that load tolerant amps do sound better in a room than those which are choosy and picky.
Let me put it this way - I think most people would be quite happy with an amp capable of delivering 50/100/180W into 8/4/2 Ohms for normal room listening. We do not all need hundreds of Watts, although of course that also depends on how big one's room is, what one listens to and at what levels. A room big by European standards, with ineffcient loudspeakers, asked to deliver concert hall levels will indeed need much power.
MP3 BETTER.
I think what told me it was the processing is knowing it was transcribed form CD. I would liken CD to raw food and good MP3 ( that is anything with less information ) as lightly cooked. It is argued that our advancing intelligence came from cooked food. That means dogs also as they befriended us. We get more from lightly cooked food. The healthy people who eat raw stuff might get less nutrients and risk e-coli from meat or organic vegetables. Never eat recooked rice as e-coli spores come alive on reheating. They resist 130 C. I often do so, I am stupid. I microwave it which might help.
Recently by chance I looked again at current drive for speakers. I am not convinced it is the easy way as the simplest criticism. I supect even tweeters benefit from amplifier damping, perhaps this is why active sounds so different? Last night I said about Geoffrey Horn using a 0R22 resistor to mimic the Naim NAP250. It struck me that there might be critical damping for each drive unit type. People writing to me suggest the only time negative output impedance works is with compression drivers, that makes sense. I really like solid core cables. 0.6mm and 0.2 mm treble. Maybe they offer more ideal Q for the driver? The effects are noticeable and helpful. If solid core is added to multi-core it sounds like solid core. Again a " MP3" type effect. What is strange is the better the speaker frequency response the better the presentation. It is tempting to think my Dynaco's having less HF would do the same. Not in a million years they would.
I hope the gentleman with the new ideas doesn't give up. I am trying to build some low cost high current chokes at work. We have found upgrading some M6 cores isn't the answer. The Jump from 20 to 25 amps is enough to ruin the recipe. I suddenly find I am between a rock and a hard place. No one in sensible cost engineering has helpful advice. We are solving the problem and cost is the only unsolved. What I might do is use 4 x 12.5 amp choke in series parallel. Space them so as not to loose inductance.
I had a feeling I might have learned something if the 3D nature of electricity had been expanded. It would have to be like the Cuban Euclid TV program, then I might see the big picture. Alas.
Reading between the lines of yesterday the frustration I had for years of telling a story came back to me. Mostly I tell the story by building something. One thing I built was described as " what planet is Nigel from". I was deeply hurt. Turns out it was a compliment!!!!! Why I was hurt also is I never asked my friend to ask this third party to measure the device. They have cloned it and it doesn't work. I can not understand that as what I build is so simple. It is like a 3 wheeled car. One less wheel and it falls over. You might guess that high performance and extreme simplicity is my credo. I built a 3 transistor high power current drive amp. It was mostly rubbish, great on guitar. At least I know how it works and sounds. I can hear it in my head as I type.
The example amp I showed yesterday is a bridge too far. For no real gain it is too simple. Fine for the job asked of it. I think I will hook it up to the Maggie's as it should be OK. Need to tidy it and remove filters. Dvv the PSU is only 2 x 4700 uF with 500 VA toroid. It is a cheap PA amp chassis. It even has cooling fans which I will put on a thermal switch. I won't go mad with it. Two extra 4700 uF and some hand wound chokes to form a RF Pi filter ( 1.25 mm wire , 20 turns x 10 mm dia should help ). All on tag strip to prove it can be done. I will use dumper to VAS feedback a la Baxendale. As it will be more or less Dead-bug I can have ideal paths. I have a hunch it will sound very fluid for want of a better way of saying it. Text books that say bootstraps need to approach 100 % positive feedback obviously haven't used a spectrum analyzer to test that statement. Even 50% is impressive. I once used 97% . It ringed. 93% as most old fashioned output stages works very well. I did see a double bootstrap FET amp. Too complicated.
DF 96 told me off some months ago as I assumed resistors in painted anti phase reduce inductance. Turns out either way works. The way the ty-rap joins them helps due to shape of the resistors. The question is would 2 or 3 resistors be better than one? Probably yes. I really fell for that, a radio amateurs book told me. Those guys usually get things right. Right solution for the wrong reason. Two resistors clamped together give about 20 % less than the arithmetical ( L1 x L2 ) / ( L2 + L1) due to proximity.
I think what told me it was the processing is knowing it was transcribed form CD. I would liken CD to raw food and good MP3 ( that is anything with less information ) as lightly cooked. It is argued that our advancing intelligence came from cooked food. That means dogs also as they befriended us. We get more from lightly cooked food. The healthy people who eat raw stuff might get less nutrients and risk e-coli from meat or organic vegetables. Never eat recooked rice as e-coli spores come alive on reheating. They resist 130 C. I often do so, I am stupid. I microwave it which might help.
Recently by chance I looked again at current drive for speakers. I am not convinced it is the easy way as the simplest criticism. I supect even tweeters benefit from amplifier damping, perhaps this is why active sounds so different? Last night I said about Geoffrey Horn using a 0R22 resistor to mimic the Naim NAP250. It struck me that there might be critical damping for each drive unit type. People writing to me suggest the only time negative output impedance works is with compression drivers, that makes sense. I really like solid core cables. 0.6mm and 0.2 mm treble. Maybe they offer more ideal Q for the driver? The effects are noticeable and helpful. If solid core is added to multi-core it sounds like solid core. Again a " MP3" type effect. What is strange is the better the speaker frequency response the better the presentation. It is tempting to think my Dynaco's having less HF would do the same. Not in a million years they would.
I hope the gentleman with the new ideas doesn't give up. I am trying to build some low cost high current chokes at work. We have found upgrading some M6 cores isn't the answer. The Jump from 20 to 25 amps is enough to ruin the recipe. I suddenly find I am between a rock and a hard place. No one in sensible cost engineering has helpful advice. We are solving the problem and cost is the only unsolved. What I might do is use 4 x 12.5 amp choke in series parallel. Space them so as not to loose inductance.
I had a feeling I might have learned something if the 3D nature of electricity had been expanded. It would have to be like the Cuban Euclid TV program, then I might see the big picture. Alas.
Reading between the lines of yesterday the frustration I had for years of telling a story came back to me. Mostly I tell the story by building something. One thing I built was described as " what planet is Nigel from". I was deeply hurt. Turns out it was a compliment!!!!! Why I was hurt also is I never asked my friend to ask this third party to measure the device. They have cloned it and it doesn't work. I can not understand that as what I build is so simple. It is like a 3 wheeled car. One less wheel and it falls over. You might guess that high performance and extreme simplicity is my credo. I built a 3 transistor high power current drive amp. It was mostly rubbish, great on guitar. At least I know how it works and sounds. I can hear it in my head as I type.
The example amp I showed yesterday is a bridge too far. For no real gain it is too simple. Fine for the job asked of it. I think I will hook it up to the Maggie's as it should be OK. Need to tidy it and remove filters. Dvv the PSU is only 2 x 4700 uF with 500 VA toroid. It is a cheap PA amp chassis. It even has cooling fans which I will put on a thermal switch. I won't go mad with it. Two extra 4700 uF and some hand wound chokes to form a RF Pi filter ( 1.25 mm wire , 20 turns x 10 mm dia should help ). All on tag strip to prove it can be done. I will use dumper to VAS feedback a la Baxendale. As it will be more or less Dead-bug I can have ideal paths. I have a hunch it will sound very fluid for want of a better way of saying it. Text books that say bootstraps need to approach 100 % positive feedback obviously haven't used a spectrum analyzer to test that statement. Even 50% is impressive. I once used 97% . It ringed. 93% as most old fashioned output stages works very well. I did see a double bootstrap FET amp. Too complicated.
DF 96 told me off some months ago as I assumed resistors in painted anti phase reduce inductance. Turns out either way works. The way the ty-rap joins them helps due to shape of the resistors. The question is would 2 or 3 resistors be better than one? Probably yes. I really fell for that, a radio amateurs book told me. Those guys usually get things right. Right solution for the wrong reason. Two resistors clamped together give about 20 % less than the arithmetical ( L1 x L2 ) / ( L2 + L1) due to proximity.
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Let me also add this note - I am in complete agreement with John Curl regarding voltage slew rates.
As he said, nobody really KNOWS just how important they are, but designing for a relatively high slew rate of say 100 V/uS is not too hard if one sets out to do it. We may not know just how much and how in general that helps, but it doesn't seem to hurt at all, so why not?
The odd thing (to me) is that so few even mention current slew rate. I realize that it is much harder to measure and is under tremendous influence of the elctrolytic capacitors, because electronics will always be faster, but still ... If I can squeeze say 5 A/uS for smaller powered amps and say 10 A/uS for more powerful versions, I'd be happy.
May not seem like much to ask, but when you think about it, we're really talking about the entire power supply section, and not only of its pure quantitative aspect, but also of its qualitative aspect. We really don't want to trade high ripple factrs for sheer speed, do we?
As he said, nobody really KNOWS just how important they are, but designing for a relatively high slew rate of say 100 V/uS is not too hard if one sets out to do it. We may not know just how much and how in general that helps, but it doesn't seem to hurt at all, so why not?
The odd thing (to me) is that so few even mention current slew rate. I realize that it is much harder to measure and is under tremendous influence of the elctrolytic capacitors, because electronics will always be faster, but still ... If I can squeeze say 5 A/uS for smaller powered amps and say 10 A/uS for more powerful versions, I'd be happy.
May not seem like much to ask, but when you think about it, we're really talking about the entire power supply section, and not only of its pure quantitative aspect, but also of its qualitative aspect. We really don't want to trade high ripple factrs for sheer speed, do we?
This started me thinking about some desk top speakers. Seems a tad optimistic.
http://www.adafruit.com/products/987
Funny thing is some people would say it sounds better with the smallest possible capacitors. Technically speaking there can be no justification for large capacitors. Ripple currents and overheating are issues that might force a decision. To paraphrase Douglas Self again. There is no evidence that oversized capacitors aid performance as these things are taken care of by good amplifier design. Mostly why big caps entered amps is the same reason the engine of a car comes into the buying equation. I remember when amps started to show off their insides for the first time. The genie was out of the bottle. With Hybrid cars we could have the old Fiat 500 CC twin make a comeback and eat an old style Porsche for breakfast. We all know that will never sell. Make it a 1600 CC six and it will. A 990 CC triple better still . I have one of those and hate the sound. A double one with shared water supply would be good . Running on 1 , 2, or plus batteries . Battery only at 30 MPH with 20 mile battery range seems the ideal equation.
I do have my own counter theory. If an amplifier is made into class A then the capacitors for many reasons need to be larger. Even then tricks can be used to avoid that. Dumpers and drivers on separate supplies is one.
My conjecture is the class A problems return in AB. They are disguised by music. The colouration is heard. I still side with Mr Self and say no way should an amplifier need more than 10 000 uF as long as the ripple current is OK and common mode rejection optimum. We mostly listen to 5 watts so that makes it doubly so. Big caps usually impart a darker sound. As someone who likes classical music that is not my preferred sound. Banking caps together seems to encourage less tight bass. Over sized decouplers seems to be a good idea. I suspect the 4700 uF of your proposal will do 90% of the work and possibly do a lot of good. Adding other caps to offset the darker sound was said to me to make it more complex. I side with that point of view. The DNM slit foil caps seem a good compromise. I do use 0.1 uF additional as do most people. Thus more is less ?
I can understand for commercial reasons doing it is not stupid. Just be aware it should have negative aspects. I suspect bringing the power in from below as I said before might help that. I would have the caps in a star with massive 0V clamp. I would prefer the computer grade caps with clamping bolts. 4 x 22 000 uF should be more than enough.
I will have 4 x 4700. It should be OK.
Does anyone here think my dislike of 16 bit CD is because master tapes sampled at 48 kHz then become 44.1 kHz. Surely things were recorded at 44.1 to avoid the problems? In don't know enough about this to know if it counts.
This just came in. Very clean!
https://www.youtube.com/watch?v=ujafIJCV4ok
http://www.sciencemuseum.org.uk/exponentialhorn
My friend Roger sent this.
This just came in. Very clean!
https://www.youtube.com/watch?v=ujafIJCV4ok
http://www.sciencemuseum.org.uk/exponentialhorn
My friend Roger sent this.
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Yes, quite possibly.
I run a Toshiba Qosmio laptop runing Windows 8.
This laptop has optical spdif output that I feed into a Behringer SRC2496. and the SRC2496 will clock to any input sample rate up to 96k.
Now here is the thing....Windows will output at the choices of sample rates provided in the playback device properties dialog.
IOW, regardless of the sample rate of the music that I am playing from harddrive, Windows converts this sample rate to choice of 44k, 48k, or 96k.
So, for proper playback, I need to select the output sample rate according to the track/album that I am playing.....when I run mismatched sample rates, the sample rate conversion audio degradation is obvious.
Are there any boffins here that can point me to how to cause the spdif output sampling rate to automatically track to the source music sampling rate ?.
Dan.
Below 96k which ones are missing? Or do you mean if you start at 44.1k it stays there no matter what the source does? I have not noticed this with external ASIO devices, in fact I have one with a math flaw that runs 6% fast at 44.1k
Hi Scott.
Yes, I mean that no matter the format of the source file, the spdif output is according to the Windows playback device setting, ie 44k, 48k, 96k in 16bit or 24bit....iow Widows does the SRC/resolution.
So far I have had to resort to manually changing the W8 playback device settings according to the source files that I am using.
Is there a freeware that can bypass this W8 internal SRC, when using a player such as Foobar2000 ?.
The spdif optical output is directly out of the laptop headphone/optical socket, and not using an external device to generate the optical spdif signal.
Dan.
Real time SRC by nature has trade-offs and there are many, some very good. I think the computational load to put absolutely all artifacts below say a 24bit noise floor is still not there real time, not sure though. Some of these are very good, but then there's Audacity in "best" mode. http://src.infinitewave.ca/
@Max Sorry I don't know of a freeware bypass.
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Ok, I found this page Perreaux High End Audio Blog: How to Setup USB Audio in Windows XP
The page advises to install ASIO4ALL - Universal ASIO Driver, and foobar2000: Components Repository - ASIO support.
I have done so, and now the display of the SRC2496 indicates the source file sample rate correctly, and it's VU meters suggest that it is outputting audio correctly.
The Windows volume control no longer works, so it looks like job done.
Dan.
.
The page advises to install ASIO4ALL - Universal ASIO Driver, and foobar2000: Components Repository - ASIO support.
I have done so, and now the display of the SRC2496 indicates the source file sample rate correctly, and it's VU meters suggest that it is outputting audio correctly.
The Windows volume control no longer works, so it looks like job done.
Dan.
You do now
.
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Nige, how many times do we have to go over this, all over again? It's starting to be very tiring.
Caps the bigger they are, the better the filterig, but also naturally slower than same type caps of smaller size. I will gladly bet that two 10,000 uF caps in parallel will beat the same type, same make 22,000 uF cap in lietrally everything, starting from available current capacity right down to the general speed.
I suggested, and I repeat - for high capacit, use 10,000 // 10,000 // 4,700 uF caps, That way, you get everything, and the only minus point is that this will require more real estate room.
Or, if you really need high capacity, use 22,000 // 10,000 uF.
If this is fed by a relatively oversize transformer, for 100/200 W 8/4 OHms say not 300 but 500 or 600 VA, then you have a mighty PSU which will not let you down.
I never understood this 'slower' thing. Do you mean they somehow give up charge slower than smaller caps? They do drop in voltage slower, everything else being equal, but surely that's what you want?
Or do you mean that they would present a larger impedance to the load, like larger parasitic induction?
Jan
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