So what is it doing? You mentioned 'Gremlins'
You said it was misbehaving. What's it doing? PM me, or move this to another thread where we can discuss this away from the noise and distortion.
You said it was misbehaving. What's it doing? PM me, or move this to another thread where we can discuss this away from the noise and distortion.
Because it's a great design
The title of this thread says it all. That idea to put in a path for a feedback cap to an internal node to speed up response during potential slewing conditions was sheer genius. You've seen the design for that oscillator using it, haven't you, that produces 1 ppm distortion in the audio band?
I don't know if ADI gave you a bonus for that one...but you got that signed copy of Kip's Teams' Nobel speech. Better late than never, huh?
As far as the AD845 goes - it might not be EOL. The datasheet I just downloaded last night wasn't waternarked 'obsolete' like the 2131's was.
It may just be that DigiKey isn't seeing enough orders, and is trying to clear out stock or is going to quit carrying the part, or just in the DIP package. They do that. That might be a good thing - I'm tracking their stock-on-shelf numbers, and if that scare tactic doesn't work, I may be able to negotiate the price down. If ADI is thinking of discontinuing it, I'll want to stock up or be prepared to start using the SM package, I've got less than 30 of the DIP ones left in my FET opamp parts drawer.
The title of this thread says it all. That idea to put in a path for a feedback cap to an internal node to speed up response during potential slewing conditions was sheer genius. You've seen the design for that oscillator using it, haven't you, that produces 1 ppm distortion in the audio band?
I don't know if ADI gave you a bonus for that one...but you got that signed copy of Kip's Teams' Nobel speech. Better late than never, huh?
As far as the AD845 goes - it might not be EOL. The datasheet I just downloaded last night wasn't waternarked 'obsolete' like the 2131's was.
It may just be that DigiKey isn't seeing enough orders, and is trying to clear out stock or is going to quit carrying the part, or just in the DIP package. They do that. That might be a good thing - I'm tracking their stock-on-shelf numbers, and if that scare tactic doesn't work, I may be able to negotiate the price down. If ADI is thinking of discontinuing it, I'll want to stock up or be prepared to start using the SM package, I've got less than 30 of the DIP ones left in my FET opamp parts drawer.
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Yes, I designed it not Mr. Bateman. Winston Smith has been at it again and the EDN archives are again apparently erased.
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1130 here, a retired machine parked at the local board of education for high school kids to noodle after class. Wrap the punch cards in waxed paper and elastic bands for the bike ride in case it rains. Guessing 1973-4?
Attachments
1 ppm Oscillator
We may be talking about a different oscillator. I've seen two (or more) designs out there. I even did one of my own, using modified Vactrol linear optocouplers so it could be made variable, and controlled by a DAC. Where was Bateman's published? Can you post a link, or PM me one?
We may be talking about a different oscillator. I've seen two (or more) designs out there. I even did one of my own, using modified Vactrol linear optocouplers so it could be made variable, and controlled by a DAC. Where was Bateman's published? Can you post a link, or PM me one?
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They should - RTL was actually not much more complicated than Darlington transistors with resistors built in. I've got some old RTL and DTL stuff I built when I was 8 years old (1965) that still runs. Might need to replace any electrolytics in there, but the logic should still function - those metal cans are hermetically sealed. Epoxy packaged stuff that old is sometimes problematic, especially if it got wet, or was stored in a humid environment, or at elevated temps, like in an attic.
I have a friend who programs with a lisp. But it's because he's old and drools a loot.
Why DIY Audio?
Because it's fun.
Because it exercises the mind.
Because you can do it after you are too old to golf but are old enough to have time to golf.
Because you can build something that has no viable commercial market, and therefore would not otherwise exist.
Because commercial products will always include added "features" that have no earthly use, but are necessary to actually sell product to the consumer space.
Because commercial products will always not include features that have perfectly good uses, but will not be included in order to actually sell product to the consumer space.
Because audio is increasingly controlled by a few, massive, monolithic players who must answer to shareholders, not DIYer's.
Because it's cheaper to sell a product that is disposable, rather than built for lifelong enjoyment, even if the disposable product would otherwise be useful for a lifetime.
Because proprietary software, which in the modern world is a rental sales model, infests everything, when hardware could substitute without the rent payment, or when user-generated code and open source non-proprietary code could substitute without the rend payment.
Because corporations are constantly lobbying to create legislation designed to prevent users from servicing their own purchased equipment if proprietary hardware and software is incorporated into the service model.
Because the environmental impact of manufacture ( not use, not disposal) of a single modern smartphone is greater than the environmental impact of manufacture of a fleet of 1960's Cadillacs. Or a pallet of Dynaco Stereo-70's.
Because a hand-crafted anything is inherently more interesting to intelligent, curious people than a manufactured anything, which is a springboard to teaching others about audio and electronics, and some of those intelligent, curious people are youth.
Finally, a story:
I have an old friend who was into motorcycles very early in life, a trained machinist, who entered the trade because of a love of bikes. To this day he has manual machine tool equipment in his garage shop. He has built one-off parts for bikes and cars all his life.
Observing people who fail to maintain their bikes, who buy then don't ride their bikes, who buy bikes for reasons that has nothing to do with motorcycles:
"They just don't give a fxxk about bikes".
We give a fxxk about DIY Audio.
Is it dying? Only if you let it. It's 100% supported by those who DIY, not anyone else, not any massive corporation, not the dull and un-interesting.
Because it's fun.
Because it exercises the mind.
Because you can do it after you are too old to golf but are old enough to have time to golf.
Because you can build something that has no viable commercial market, and therefore would not otherwise exist.
Because commercial products will always include added "features" that have no earthly use, but are necessary to actually sell product to the consumer space.
Because commercial products will always not include features that have perfectly good uses, but will not be included in order to actually sell product to the consumer space.
Because audio is increasingly controlled by a few, massive, monolithic players who must answer to shareholders, not DIYer's.
Because it's cheaper to sell a product that is disposable, rather than built for lifelong enjoyment, even if the disposable product would otherwise be useful for a lifetime.
Because proprietary software, which in the modern world is a rental sales model, infests everything, when hardware could substitute without the rent payment, or when user-generated code and open source non-proprietary code could substitute without the rend payment.
Because corporations are constantly lobbying to create legislation designed to prevent users from servicing their own purchased equipment if proprietary hardware and software is incorporated into the service model.
Because the environmental impact of manufacture ( not use, not disposal) of a single modern smartphone is greater than the environmental impact of manufacture of a fleet of 1960's Cadillacs. Or a pallet of Dynaco Stereo-70's.
Because a hand-crafted anything is inherently more interesting to intelligent, curious people than a manufactured anything, which is a springboard to teaching others about audio and electronics, and some of those intelligent, curious people are youth.
Finally, a story:
I have an old friend who was into motorcycles very early in life, a trained machinist, who entered the trade because of a love of bikes. To this day he has manual machine tool equipment in his garage shop. He has built one-off parts for bikes and cars all his life.
Observing people who fail to maintain their bikes, who buy then don't ride their bikes, who buy bikes for reasons that has nothing to do with motorcycles:
"They just don't give a fxxk about bikes".
We give a fxxk about DIY Audio.
Is it dying? Only if you let it. It's 100% supported by those who DIY, not anyone else, not any massive corporation, not the dull and un-interesting.
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I think speakers are probably the last area where you can build better value for money items than ready made
That's OK - I have the EDN "Ideas for Design" article, and the follow-up.
Who was Bateman? Jim Williams also did a design and put it in one of his famous app notes and said he dearly regretted it - "...next thing you know, my phone is ringing off the hook and every dang audio nerd in the Valley is bugging me...."
I think there was also a circuit in one of those dictionay-sized applications seminar books in '92, and one in "Audio Amateur". Some of the designs were flawed, though - fixed, not variable frequency, or so susceptible to interference that you practically had to run them in a mil-spec Faraday quiet room on batteries, with the lights out, and make measurements with a pencil and paper by candlelight.
Now you're talking. People laugh, but with a few mods, you can get it to make actual bass, and completely eliminate all hum and the hiss from that stupid choice for an input tube.
Mine is so quiet, I can only hear it running if I kneel down and put my ear right up next to the tweeter on one of my LaScalas. But it will play Beethoven symphonies and Wagner operas at orchestral levels.
$40 at a swap-meet.
70-100 watt per channel amps for upwards of $1000, $2000, $3000?
Standalone High-End DACs, room-EQ processors, phono stages from boutique audio stores or poseurs who don't know an oscilloscope probe from their cazzo?
Plenty of motivation for DIY there....
White Noise does not exist?
Never driven past a trailer park in the South on a Saturday night, huh?
Never driven past a trailer park in the South on a Saturday night, huh?
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the problem with the electronics is that there's more and more of it requires a level of knowledge that many don't have, they can't design or debug switching amplifiers, DACs and the like too easily. Even the equipment is more expensive and complex. So you end up buying modules. Speakers are already like this, all we do is add the woodwork, the hard part, the real tech, is in the driver and we simply buy them. The 2nd hard part is the XO and there we still have some scope.
Back in the day, things were simpler, you didn't require as much knowledge or kit to make stuff.
Back in the day, things were simpler, you didn't require as much knowledge or kit to make stuff.
My favorite CPU chip for doing assembler. I wrote a native FORTH for the TeleSketch (neve made it out of development) and a set of floating point instructions so lots of assembler.
dave
I hated having to do a course that required programming in COBOL. Such a clumsy language.
dave
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