I once built a 1500V/us power amp for VMPS with 64W class A and 250W class A-B. This was about 1981. We took it to CES in winter and it overheated the hotel listening room even though it was snowing outside, and we tried to leave a window open. I used 3 whisper fans on 3 separate airblown heatsinks and it still just about melted down.
Anyone want to buy it? It is at my office. Needs a little TLC and won't be cheap, but an interesting design. Still owned by VMPS.
Anyone want to buy it? It is at my office. Needs a little TLC and won't be cheap, but an interesting design. Still owned by VMPS.
Except for using current sink loading instead of resistors, isn't this part similar to an AD845? The AD845 has lower bandwidth, but better slew rate, better "power bandwidth", and better settling time. Plus you can still purchase them...
Of course, this Harris part was pretty remarkable for its time.
Of course, this Harris part was pretty remarkable for its time.
The AD845 appears to have been introduced 10 years after the HA5110. Who were the HA designers, anyone know?
if anyone has access, i think this may be mentioned in the trade rag "electronic design" for 1979 or so. they used to run special analog highlights issues every year to talk about new hot parts that had just come out.
i was ordered to get rid of mine a long time ago ...
mlloyd1
i was ordered to get rid of mine a long time ago ...
mlloyd1
john curl said:
My Analog Devices handbook dated in 1988, shows the AD845 as 'preliminary technical data' in the data book pp 2-163, 164
A real mystery, but they may have been doing more military than consumer, and so kept out of the limelight.
Syn08, maybe you want to google for Scott's name. Especially in combination with 'AD797' or 'Analog devices fellow'. You will see his quote in a different light then. In fact people with such a great sense of humour and a bit of irony are so seldom, it's a real pity.
All the best, Hannes
I've known Barry Harvey for a long time. He was at Elantec before the buyout. I don't think he was at Harris, but I have some friends that were. I suspect the guilty parties are from the days of thin black ties and white shirts, military style flat top haircuts required🙂 . As I recall the military bankrolled a fancy DI process for Harris. That design is what I would consider a little "gothic" way to complicated for the HP-35 and breadboard style of design so I also suspect they had their own mainframe for early simulation (I could be wrong). We used to buy/resell some of these amplifiers (mostly to military customers). The days of $65 mil-spec IC op-amps. BTW 50V/us for a DE-compensated op-amp is pretty slow. I sponsored a thread last week on classic discrete op-amps where in the same time frame they were at 2GHz GBW and 1200v/us.
I'm glad Hannes got my joke. I do love British satire
I'm glad Hannes got my joke. I do love British satire
Oh, THAT was the joke. It comes from 'Animal Farm' by George Orwell when the animals say:
'Four legs good, two legs bad' in his satire on Communism.
'Four legs good, two legs bad' in his satire on Communism.
Come on! Made me spill my coffee 😀
I find it so cool I even use it as my signature - though I know that people are going to misunderstand it and think I'm against ICs 😀
(Disclaimer:
I'm not against ICs, it's just that I feel unemployed by using them - a phono stage made from a single IC??. What's left for me todo then?)
The Brits have really a fine sense of humour!
All the best and I hope you stay here, Hannes
It's hard to see the 5110 schematic but on a closer look I guess it's not far off from some of the discrete op-amps of the day. The use of FET interstage coupling mostly became deprecated after the module days. The choice of source followers on the input rather than using the FETs as the input pair is still a valid one, examples of both are still current.
I also remember that the last thing Dick Burwen did here was build a settling time fixture for one of those Harris op-amps, that I inherited .
It broke one quarter and I thought we were going to have a full military inquiry because the parts ended up in some nuke subs.
I also remember that the last thing Dick Burwen did here was build a settling time fixture for one of those Harris op-amps, that I inherited .
It broke one quarter and I thought we were going to have a full military inquiry because the parts ended up in some nuke subs.scott wurcer said:
Yup, I remember that very well, Scott. Also the SOS (silicon-on saphire) CMOS logic by RCA. Harris was called Radiation back then, and then they bought RCA's CMOS line. DI was the only way we could get through the military nuclear hardening requirements. Bendix worked very closely with Scandia Labs when they were in the semiconductor business, making super-beta transistors that would maintain sufficient hfe and low enough leakage to continue to operate after the nuclear "event" test. Hardened PNP devices were especially difficult to make, and very susceptible to permanent damage.
Very interesting work, but the data items went on forever and qual testing was very intense. Each bombarded device came back in a lead-lined box with a big yellow radiation warning decal on the cover, and in the early days the devices were accompanied by a Scandia official to ensure proper handling and test and safety for the personnel involved.
Chuck Hansen
I gave SY a clearer view of the schematic, but he has not posted it as yet. Perhaps it is the format of my scan that has caused a problem. Dimitri has it as well, but he has not put it up either.
I've only gotten one Harris sheet from you, the one I posted. If you have a clearer one, send it along and I'll swap it out.
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