But times the 250 or so he did! As I get older I find I want complete sets!
Wow Brad,
Complete agreement on this site. John Eargle was a fine person, a gentleman, a superb recording engineer and knowledgable about all areas of sound.
I assume you know the story of when he didn't show up to meet Bill G at the airport to give a talk, Bill called Mark G to check on him. Mark made the discovery of his passing and was seriously affected for a few days.
Complete agreement on this site. John Eargle was a fine person, a gentleman, a superb recording engineer and knowledgable about all areas of sound.
I assume you know the story of when he didn't show up to meet Bill G at the airport to give a talk, Bill called Mark G to check on him. Mark made the discovery of his passing and was seriously affected for a few days.
I'd really like to see this too. How soon can you send a pic?
tl;dr does not apply. I know what I don't know, even though the initial premise was a fun read when applied to diffuse conductors.
Over time multiple physicists who specialize in QM who have said, that nobody, even they do not understand it. I still cannot get my mind around the concept that suspends the arrow of time constant, instead being inverse. Immense respect for those here who have the background and faculty to understand quantum entanglement at a level that approximately models the behavior.
A skim of the material makes it clear that of all the sets of "the classical model" involving solder, perfboard, point to point and circuit engineering at our comparatively sauna-like working temperatures of normally greater than 273 degrees kelvin are exclusive to the required assumptions of QM modeled interaction behaviors at these levels of observation.
Pardon me while I go down to the convenience store down the street. I need to refresh my supply of liquid helium. They have a Dewar exchange. Better than blue rhino. Maybe then I can figure out a way to demonstrate these principles using my camera strapped to my child's telescope pointed at my kegerator with a REELY bright light shining at it and fstop maxed out. http://cheezburger.com/5361754368
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Since the conversation with John about his design has gone so off the rails I thought I would bring up another subject. What is the current thinking and state of the art in regards to audio of switch mode power supplies? Have we gotten past the problems and are there some real solutions that will allow using these power supplies or are we still dealing with degradation of the sound due to problems with these supplies?
Yes. He was on the couch and had been reading the newspaper. Congestive heart failure.
I don't think there are real problems with using smps, but a lot of immaginary ones. Latest AP uses smps afaik because with linear supply they could not get rid of 50/60 Hz totally.
Vacuphile,
Thanks for the reply. Yes I have read all the objections to using a smps and the only one that truly concerned me is the injection of noise into the rest of the system through RF. I just can't see a way to use a standard supply inside a self powered speaker that won't take up way to much airspace. That is my motivation to look at an smps. Purely on a size basis.
Thanks for the reply. Yes I have read all the objections to using a smps and the only one that truly concerned me is the injection of noise into the rest of the system through RF. I just can't see a way to use a standard supply inside a self powered speaker that won't take up way to much airspace. That is my motivation to look at an smps. Purely on a size basis.
John,
I understand you not wanting to or needing to use a smps, why if you have the space and cost is not an object do it. But I am on the other end of the story and size is the driver in this application. An external power supply just goes against the whole idea of a self powered speaker.
I understand you not wanting to or needing to use a smps, why if you have the space and cost is not an object do it. But I am on the other end of the story and size is the driver in this application. An external power supply just goes against the whole idea of a self powered speaker.
Not according to Hofer as to the motivation, although it did have that effect.
Bruce said he was dubious, initially, about the switcher, and they worked very hard to find an acceptable supplier. And they are not cheap. The key component was a very good common-mode choke, I believe he said a 1 mHy one (mutual inductance).
I asked him about the output noise and it was a few millivolts p-p. I had to remember the "I'm sorry, I'm from California" defense of trash talk when I told him I'd called B$ on someone who posted that switchers now had noise in the low microvolt region, on another forum. And no, the person who asserted this did not mean after a cascaded LDO.
Brian Cheney did have his prejudices, like not using horns in his speaker designs, BUT he did use a tweeter to get the extended frequency response necessary for the greatest detail, unlike many of you here. What reminded me of where I am at when it comes to audio, is his acceptance of 'what he hears, is' he was very steadfast in that, even rejecting a brand new power amp design that I loaned to him for a CES show, because he did not like the way it sounded. What a disappointment! I just designed this 350W/ch power amp and MEASURED it in my lab, with flying colors! How could he NOT like this amp? Of course, in those days, I didn't bother to listen to it myself, too much trouble, just measurements. '-) Sound familiar anybody? Taught me a lesson, when I got a second opinion of the sound of the same amp by my then CTC business partner, Bob Crump, who didn't like it either, and neither ultimately did Stereophile, SO Bob and I had to find out what was wrong, and I donated the amp to Bob, and we modified it, until it sounded so good, that we went into a minor business of modifying them for our friends. A lot of work, and expensive when it came to warranty. I was stuck fixing them if a client blew one up. We had a special client who blew two power amps and a CTC preamp (both channels) before we gave up on him. Problem in his system? You bet, but he was in Europe, and difficult to visit to find the problem at the time. We finally gave up, it was too much work for what we got for it, BUT it led to the development of the Parasound JC-1, where we really did get to do it 'right' (trust me, most of you would not believe what is right, if we told you) and of course went to Class A status with Stereophile. And that is the secret to my 'success'! '-)
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DIY EBAY SMPS's are what they are .... pirated , ill conceived , cheap chinese
junk , just like most other things (from china).
For 20-40usd$ , what do you expect ?? I'm sure (with research) , a much cleaner
"audiophile" grade design could be created. Hypex SMPS's are a step in the right
direction ... some others are even shielded with great attention paid to
shielding and filtering. These are not <40usd$ !!!
OS
OS,
I can imagine that most of the Chinese stuff on Epay is junk most of the time. Not looking to do that. I'm sure there are some truly adept at making them work on a high level but I don't know anybody in the realm. I have somewhere a smps that was inline but not enough power to run an amplifier without chocking it with a lack of power, I don't think you can find one over about 60 watt output inline so I need to have one internally. Not sure how the price of an smps compares to a large transformer and all the rest of the parts for a good power supply but I would think they could be comparable in cost. The Hypex units are damned expensive from what I looked at in the past.
I can imagine that most of the Chinese stuff on Epay is junk most of the time. Not looking to do that. I'm sure there are some truly adept at making them work on a high level but I don't know anybody in the realm. I have somewhere a smps that was inline but not enough power to run an amplifier without chocking it with a lack of power, I don't think you can find one over about 60 watt output inline so I need to have one internally. Not sure how the price of an smps compares to a large transformer and all the rest of the parts for a good power supply but I would think they could be comparable in cost. The Hypex units are damned expensive from what I looked at in the past.
Degradation ? Exactly the contrary.
Lazy cat had tried, and chosen an SMPS for its VSSA and First one amps...because it was sounding better.
(He seems to prefer non regulated ones.)
And those amps are CFAs, reputed for their reduced PSRR.
And this was my opinion since years too.
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I see only two issues....... the radiated emi/rfi issue which can be handled with proper shielding; and, the conducted noise on the ac power lines.... to which all your other gear is also connected.
THx-RNMarsh
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Kindy,
I think this is the usual confusion over preamps and power amps having quite different requirements. Mean Well makes a complete line of switching power supplies that meet the standards for safety, power factor and noise.
Now if you are using a ratiometric switching amplifier then power supply noise can be an issue. But using an AB linear amplifier it should not be an issue if you give the amplifier and power supply both a bit of distance and some breathing room.
One technique is to place the heatsink of the amplifier in the bass port for a bit of extra air when under increased power demands.
BTY I would not expect any benefit from special kinds of wire at other than very low signal level. Another one of those power/preamp distinctions.
I think this is the usual confusion over preamps and power amps having quite different requirements. Mean Well makes a complete line of switching power supplies that meet the standards for safety, power factor and noise.
Now if you are using a ratiometric switching amplifier then power supply noise can be an issue. But using an AB linear amplifier it should not be an issue if you give the amplifier and power supply both a bit of distance and some breathing room.
One technique is to place the heatsink of the amplifier in the bass port for a bit of extra air when under increased power demands.
BTY I would not expect any benefit from special kinds of wire at other than very low signal level. Another one of those power/preamp distinctions.
ES,
So the name of the company is Mean Well? I will look and see if I can find them. This will be a class ab amplifier and I take your and Esperado's recommendations to heart. When you talk spacing between the smps and the amp how much distance are we talking here? I guess a shield could be incorporated that would help with the emi/rfi between the supply and amp.
So the name of the company is Mean Well? I will look and see if I can find them. This will be a class ab amplifier and I take your and Esperado's recommendations to heart. When you talk spacing between the smps and the amp how much distance are we talking here? I guess a shield could be incorporated that would help with the emi/rfi between the supply and amp.
You need to measure this for yourself, as I have, and also see what you get on the ac power line. The spectrum of noise frequencies is quite broad.
THx-RNMarsh
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Place them close to each other and listen, move them apart until you don't hear a difference. Then three times that distance should be great. If the test takes more than five minutes then we can talk what to measure.
Shielding is nice but actually a bit tricky.
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