My thought too... I'm like hey maybe I'll give him a few suggestions... (maybe we'll work something out) but then I see that and I'm clueless.
I am overseeing a total project that involves other professional engineers. I just hope to catch any oversight that any of us might do that would make this future product less successful than it could well be. I have a reputation to uphold, and I don't want to compromise it by ignoring subtle details.
I have been interested in Class D since a fundamental article on a Class D power amp appeared in Wireless World in April, 1965. Heck, I was not even out of college yet. Most have been disappointing, however, including ICE, Tripath, but we have had some luck with a pair of Brunos switching amps as variable switching regulators in an amp we designed almost 10 years ago. I am using it in my lab at the moment. My new designers are not Bruno's, but they appear to be extremely competent. We shall see.
Please don't bother to 'help' me too hard, you 'hear no difference' guys. You are usually barking up the wrong tree, so you don't have to bother me with the usual stuff. However, thanks for trying. '-)
Please don't bother to 'help' me too hard, you 'hear no difference' guys. You are usually barking up the wrong tree, so you don't have to bother me with the usual stuff. However, thanks for trying. '-)
Do you mean 'problems' as in sound quality problems? Harsh treble seems to be a common refrain, in somewhat better designs perhaps 'bleached tonal colours' ?
Oddly enough though it comes from the same quarters who say silver cable sounds 'bright'. looking at reviews of the hypex based amps out there (basically everyone except HK in the high end space as far as I can tell) and NO ONE is complaining of harsh treble or bleaching.
I kind of like to work for whatever I get compensated for. That is why I am going out of my way to be diligent in this Class D project. Yes, my name will be mentioned somewhere at some level, and I want everything to be the best possible, not just 'good enough for double blind tests'. The basic design already does that, but I want to add even more, if possible. Perhaps it is not possible, we shall see.
It's a myth that you don't benefit from giving freely - but WHO you give freely to and WHY makes all the difference.
PS. Not saying anything about John here.
OnSemi is opening a factory in Vietnam for TO-220 BJTs. I wonder how different they will be from the others?
http://www.mouser.com/PCN/ON_Semiconductor_21087X.pdf
http://www.mouser.com/PCN/ON_Semiconductor_21087X.pdf
Assembly and test. Not wafer fab. Assembly and test.
Attachments
Reduce EMI In Your Class D Amplifiers | Analog content from Electronic Design
https://www.maximintegrated.com/en/app-notes/index.mvp/id/3973
https://www.maximintegrated.com/en/app-notes/index.mvp/id/5342
Results of five second searching.
IMO, radiated RF is the subjective Class D killer.
Some individuals are sensitive to local sources of EMR....not so much the level as the 'nature' or spectrum of the magnetic disturbance.
The are ways of rendering this EMR innocuous ime.
Dan.
Oooooooooh. Sorry.
Well how about this one:
http://www.mouser.com/PCN/ON_Semiconductor_20349A.pdf
So, I wonder how different the Japan fab transistors are from the Malaysia? Has anyone tested it?
Here they are changing the TO220 shape slightly:
http://www.mouser.com/PCN/ON_Semiconductor_20645.pdf
Here they are making the dies smaller! I wonder what affect that had?
http://www.mouser.com/PCN/11273014.pdf
Well how about this one:
http://www.mouser.com/PCN/ON_Semiconductor_20349A.pdf
So, I wonder how different the Japan fab transistors are from the Malaysia? Has anyone tested it?
Here they are changing the TO220 shape slightly:
http://www.mouser.com/PCN/ON_Semiconductor_20645.pdf
Here they are making the dies smaller! I wonder what affect that had?
http://www.mouser.com/PCN/11273014.pdf
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On ferrite beads - H/K has a long history of using ferrite beads in parallel with a 10...100 Ohms resistor. However, they use them between the driver and output transistors. That's been going on for the last 25 years or lomger. May be worth considering.
That's odd, Dan, I find some of them very pleasant for all day long listening. That said, it is understood that while they all come from the same company, they do not all sound the same, in fact they sound quite different. H/K is a company which does not have a fixed sound "of their own". I have four of their amps (two integrated and two power amps) and they are not nearly the same.
The cheapest and oldest among them, the 6550 integrated amp, with a very minor modification (changing the original volume pot for an ALPS blue) in fact sounds far better than you'd expect for its price, and I daresy better than any other I know of in its price bracket. The 680 integrated amp, their top of the line in 1998, is not memorable in any way, nor does it stand out in general. If anyhting, it errs on the boring side. The Citation 100W power amp sounds a bit on the cautious side, as if it were lacking a little "oomph", but hardly tiresome. The big brother, PA 2400, is the best of them all, it has everything it should have, yet it's very easy going, almost taunting you to turn it up, which you are free to do, you'll simply get more of the same, but louder, with no tonality change.
The cheapest and oldest among them, the 6550 integrated amp, with a very minor modification (changing the original volume pot for an ALPS blue) in fact sounds far better than you'd expect for its price, and I daresy better than any other I know of in its price bracket. The 680 integrated amp, their top of the line in 1998, is not memorable in any way, nor does it stand out in general. If anyhting, it errs on the boring side. The Citation 100W power amp sounds a bit on the cautious side, as if it were lacking a little "oomph", but hardly tiresome. The big brother, PA 2400, is the best of them all, it has everything it should have, yet it's very easy going, almost taunting you to turn it up, which you are free to do, you'll simply get more of the same, but louder, with no tonality change.
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