Hi WJ; The C of cables for power amps should be a minor issue (other than stability issues)... there is plenty of current to charge it fast.... just the opposite for low level interconnects. I found there is similar improvment to a zobel at the speaker end of the cable --- just use a low value resistor (<50 Ohms) across the terminals at the speaker. yes, it wastes a little power, but it does put limits on the Z variation and terminates the line at low Z which also helps reduce RFI pickup. You can hear a change when you do this on some systems. Thx-Dick Marsh
Walt posts here under his own name, no dopplegangers allowed. I think I know the pooge.
No, the JC-3 was MY work. The ML-2 was BASED on my earlier work, the JC-3. IF the ML-2 was unstable, then blame Tom Colangelo. He was responsible for the details.
He also designed the ML-3 which was NOT BASED on my earlier work.
Tom was a technician up to the time that Mark and I separated permanently in 1976. I only spoke to Tom once in my life, at a JUNE CES in Chicago. He got a promotion, somehow. Office politics probably. There was another engineer in between, who got 'bumped off'. His name was George Mayhew. I don't know what happened to him.
He also designed the ML-3 which was NOT BASED on my earlier work.
Tom was a technician up to the time that Mark and I separated permanently in 1976. I only spoke to Tom once in my life, at a JUNE CES in Chicago. He got a promotion, somehow. Office politics probably. There was another engineer in between, who got 'bumped off'. His name was George Mayhew. I don't know what happened to him.
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Will the real POOGE pls stand up -
Now there are two POOGE guys running around and both from the same state? Do they know each other? -RNMWalt posts here under his own name, no dopplegangers allowed. I think I know the pooge.
I think it's Walt's partner on one or more Pooge articles, we all had lunch together around the time CD player mods and op-amp rolling got started. It seems Walt can't post them all. BTW I want to thank Walt for mentioning that I showed him how to use the comp pin on the AD744 to bypass the output stage.
There was a comment elsewhere concerning audio applications on datasheets and the current lack thereof. There was a golden age where Walt, I, another designer Wyn Palmer, and at least one marketing manager were able to spin a lot of audio related stuff into our applications literature/data sheets. We even had lunch with John Dennison and tried "rolling" the AD846 into the JC-80. The powers that be eventually decided that this was basicly aimed at hobbyists and slowly squashed it. Walt's articles did get good business at ADCOM and SONY so in the end everyone won and we moved into the age of "The perfect sound forever". I also remember one of Wyn's op-amps getting designed in by a high end CD player re-boxer, but I think they are long gone.
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Hi Scott,
as you are in this sentimental mood, may I ask you, was it Acculinear? As I remember it measured as AD840
I thought it was EAD and it was IIRC an AD841, but you may be right. They came in to ask for a custom part number to hide the substitution.
EDIT - The same people I see so you are right.
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Okay so it is a voltage feedback amp. But I don't understand why it is called a hybrid.
Yeah, it was used for anything but audio. The datasheet mentioned about DAC output application tho (due to its high speed). But I don't think I will revisit I/V circuitry anytime soon so the cans are still doing nothing.
And even here, the risk is not so important: If you share some new idea you had, people will fight endless against, just to look smart.
Ha! You know at least one reason not to share...
And not only to look smart, but indirectly to make you like a fool. Okay, you think it is not important. But don't you know that one important reason people share something is for self esteem? They don't need money (because most of them are not businessmen). What they need is people recognition, pride.So what do you think of sharing something (that you think is) important and what you get is humiliation instead of pride? (And some smart ashes quietly make use of the information and become popular?)
I like coding. When I was young I dreamed to have a software company. I could make software with complex functionality but unfortunately I didn't have the knowledge to protect the software from being copied. May be it was my mistake to not pursue it.
Luckily I'm emotionally "stable" (or not?). I still can smile when a software that I developed was become somebody else just because he added one or two lines (which is far less than 0.1% of the code).
I'm not like most of IT guy. I always try to make a system that will run smoothly even when I'm not there anymore. But sometimes I think, why not just create one that is so complicated that no one will be able to learn anything from the code.
Yes,
it is the same John Hagelin! John Hagelin - Wikipedia, the free encyclopedia
Physics and audio don't always mix.
Well Scott, your choice of the AD846 was a good one. Frank Dennison did NOT pay me all the royalties that I had contracted for. He was very proud of that fact.
That is probably why he wanted to replace the JC-80 with an IC, since he was NOT getting any further support from me. Always a 'sore point' royalty collection with both Dennison and Levinson. That is one good reason why I am not wealthy like many of my contemporaries, who I saw become millionaires from the audio business.
You see everyone, I was NEVER paid a full salary for my designs and development, usually just enough to keep going, and if anything at all, like $1000/mo for the development of the JC-80, and I had to use my own lab and test equipment. The ROYALTY was supposed to make up for this, if and when the product became successful. Unfortunately, with Mark Levinson, I did everything on TRUST, or even with an contract, the manufacturer was 3000 miles away and I could not afford to sue, like for the JC-80, when they balked at paying me my promised royalties.
I did NOT create VENDETTA RESEARCH for no reason at all.
I say to each and everyone: IF you think you can do as well with a good IC, that you can with an ALL DISCRETE FET design, then go for it. In fact, why not try the LT1360 or the AD846, and see what you get?
That is probably why he wanted to replace the JC-80 with an IC, since he was NOT getting any further support from me. Always a 'sore point' royalty collection with both Dennison and Levinson. That is one good reason why I am not wealthy like many of my contemporaries, who I saw become millionaires from the audio business.
You see everyone, I was NEVER paid a full salary for my designs and development, usually just enough to keep going, and if anything at all, like $1000/mo for the development of the JC-80, and I had to use my own lab and test equipment. The ROYALTY was supposed to make up for this, if and when the product became successful. Unfortunately, with Mark Levinson, I did everything on TRUST, or even with an contract, the manufacturer was 3000 miles away and I could not afford to sue, like for the JC-80, when they balked at paying me my promised royalties.
I did NOT create VENDETTA RESEARCH for no reason at all.
I say to each and everyone: IF you think you can do as well with a good IC, that you can with an ALL DISCRETE FET design, then go for it. In fact, why not try the LT1360 or the AD846, and see what you get?
I'm afraid I can't. When I said "see" the input protection, I meant physically. I would take the silicon chips directly out of the waffle pack, have them diebonded to a header or substrate, wirebonded to the package terminal pins, test the device to verify it meets manufacturer's stated parameters, and perform a high power visual inspection of the die in the event something on the die did not meet specification. Sometimes it was static discharge damage, sometimes the wirebonder would crack the sio2 or junction immediately beneath the ultrasonic ball bond, sometimes a scratch on the top surface smearing metalization, sometimes a scratch which caused emitter dip failure, reach through of a diode, excessive spot gain on a larger base device. My present job does not entail the use of a 300-400x polarized metallurgical microscope.
A hybrid is a device which is made using individual silicon chips, resistors, capacitors, and the occasional inductor epoxied or soldered to an alumina, beryllia, aluminum nitride, or sapphire substrate to create on a very small scale what we would do with a circuit board. It allowed chips of different technologies such as high voltage powerfets, low voltage low noise ic's, large and small value resistors, scr's, led's, whatever... to be used in a very small package. The linked device may have ten or 20 seperate components within.
Basically, most of the silicon components you will ever use** are chips which are less than 1/4 inch square. Most of the real estate on a PC board is packaging.
note** CPU's, memories, very high power chips, and hockey puck devices are exceptions to the 1/4 inch of course, I've played with 3 inch diameter diodes.
jn
"Raja of Invincible America" sounds like a candidate for Avatar.
jneutron, you have to know this guy he was/is? in your biz right yes/no?
Here are some slides from a talk I gave this week.
The first one is a simple full wave power supply. The transformer was 24VCT 12A the rectifiers 1N4007 the capacitor 470 uF and a load resistor of 50 ohms.
The second is the current pulse on the transformer secondary as monitored across a .1 ohm resistor inserted in the center tap lead.
The third is the noise spectrum.
The fourth is the Fletcher Munson curves that can be used to see that the noise at 3-5k is perceived as louder than the 60 hz. fundamental
The fifth is a plot of input voltage vs distortion for a bunch of small amplifiers. NOTE that some of the amplifiers do not have the distortion continue to fall until clipping begins. These are noise limited amplifiers.
So what was the point of these slides?
The first one is a simple full wave power supply. The transformer was 24VCT 12A the rectifiers 1N4007 the capacitor 470 uF and a load resistor of 50 ohms.
The second is the current pulse on the transformer secondary as monitored across a .1 ohm resistor inserted in the center tap lead.
The third is the noise spectrum.
The fourth is the Fletcher Munson curves that can be used to see that the noise at 3-5k is perceived as louder than the 60 hz. fundamental
The fifth is a plot of input voltage vs distortion for a bunch of small amplifiers. NOTE that some of the amplifiers do not have the distortion continue to fall until clipping begins. These are noise limited amplifiers.
So what was the point of these slides?
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