A letter is missing to make a "good" word...
Let say that although known at the time , slew rate
issues werent very publicised prior to his papers..
I don't think I have the schematic in electronic form, I think I have a scan somewhere.
As for my book, trust me, you are NOT interested in it. Why would you want to concern yourself with how PC do work processing in ChiWriter, WordStar and WordPerfect 4.2? You see my point? It was interesting then, but is now of zero interest.
Really?
I feel at the brink of a revelation here, because the 35+ years have clearly shown that he was quite right regarding MOST things. And the fact that he did say a few words about slew rate has since been misconstrued that he was the background for the "Slew Rate Wars", which raged among the Japanese manufacturers in the second half of the 70ies (notably with Sansui, Kenwood/Trio and Pioneer). These days a need for both voltage and current slew rates is recognized, but has been cut down to much more reasonable numbers.
I salute your courage in making such a flat out statement. It takes a lot of guts to say something like that and offer not a single actual argument how so.
You are, of course, free to think whatever you like, just as I am. I feel people who say such things are usually hotheaded glory hunters. Otala has proved himself many times over, among othe things with the Citation XX, a myth unto its own right - what have you done?
"JLH" as in John Linsley-Hood?
How did he influence JLH, pray tell? Made JLH contenmplate suicide?😀
If anything the 35 years have shown how wrong Otalla was, numerous studies including whole teams of top electronic engineers designing analog circuitry for manufacturing have shown and proven that he was wrong.
Usually only those with no formal education in electronics nowadays dispute the fact and this can be widely seen as can be here at Diyadio.
Please share written papers or proof of whatever kind that shows that Otalla was indeed correct.
The citation XX is just a CFB topology amp, nothing special about it. Whoever designed it probably copied it from the japanese firm Pioneer which had first designed such a circuit and sold it as a commercial product a year or two earlier than HK. BTW the XX has feedback, and this in the form of the usual amounts found in a CFB feedback topology (Actually it is higher than usual as it uses a cascoded vas). Granted it is lower than in VFB topologies but that is the topology particulars. Strange enough the Pioneer should be more highly regarded as this doesnt use feedback at all.
On what basis is it "a stupid remark"? I am afraid it is you who's betraying your heroic ignorance.🙂
For example see below:
http://www.diyaudio.com/forums/soli...-self-wants-your-opinions-95.html#post3531648
To reiterate, Otala's notion, for example, that an amplifier should have a forward path bandwidth that exceeds the audio band is just plain silly; there is no kinder way to put it. Moreover, his assertion that major loop feedback is only good in moderation is utter drivel. This has misled thousands of people like you and DVV for over 30 years, and is responsible for millions of substandard amplifiers being produced as a result.
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/OT
Nowadays, all Airbus pilots are trained on a flight simulator. The Air France pilots are the worst, they even haven't learned how to recover from a stall. So, maybe your sun is even a better pilot than his French 'colleagues'. 😉
Cheers, E.
Nowadays, all Airbus pilots are trained on a flight simulator. The Air France pilots are the worst, they even haven't learned how to recover from a stall. So, maybe your sun is even a better pilot than his French 'colleagues'. 😉
Cheers, E.
We almost agree on something for once. 😀 An audio amplifier should have a full power bandwidth >10kHz would not be a wrong statement, obvious maybe.
Forgive me asking . Should I ignore this in the PDF below ? In the past for my own practical reasons I have dismissed it as advertising hype . Recently I thought I saw why it mattered . I would be happy to go back to my old ways of thinking .
Possibly you didn't mean to imply that these tests are invalid ? Perhaps it was the forcefulness of the arguments some people make ? I always said if the need was true in the way suggested the tweeters would have a hard time . I asked once where do these signals come from ? I was told SACD and MC pick ups . If SACD surely the player is defective ?
My amp has a slew rate of 35 V/uS and 100 watts . I think it might just be hi fi ? Distortion is very low at 50 kHz .
http://jockohomo.net/data/7470.pdf
Possibly you didn't mean to imply that these tests are invalid ? Perhaps it was the forcefulness of the arguments some people make ? I always said if the need was true in the way suggested the tweeters would have a hard time . I asked once where do these signals come from ? I was told SACD and MC pick ups . If SACD surely the player is defective ?
My amp has a slew rate of 35 V/uS and 100 watts . I think it might just be hi fi ? Distortion is very low at 50 kHz .
http://jockohomo.net/data/7470.pdf
The measurement method and procedures are correct and were original at the time.
The interpretation of the results is questionable (and partly flat wrong). This was discussed ad nauseam on this forum and elsewhere.
Two points:
1. I have been in similar discussions for years, and am sick of them. Consequently, I have no desire whatsoever to go down that totally futile road again, I'm too old (60) to know everything, and
2. I am not on trial here, and you are inverting the issue. I said something, you challenged me to prove it while stating the opposite, rather than showing proof that you are right and not me. Do your own homework.
Over the years, I have designed and made 5 amps, strictly for my own use and private use of my close friends. All of them were based on the low global NFB principle, and, to the ears of my friends using them and mine, they sound better than most of them out there. For us, that's quite enough andnone of us are interested in pursuing the matter further.
Whoever disagrees, as is their right, are free to do it in another way. The very saying "All roads lead to Rome" instructs us that there at least several ways to do it, so we and in particular I accept that.
Why can't you?
What's next? Someone telling me only one topology really works, and for any other topology that it doesn't really work, I just imagine it?
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Absolutely correct. And his power amplifier design in the JAES (Dec 73) was a joke.
However, as I discovered when I tried to put a version of it into production, not a funny joke.
A hifi journalist once told me that I had single-handedly held back amplifier design for 30 years. A considerable feat, if true.
But it is something like true for Otala.
If you will remember, Nige, in the other thread we discused this and came to the conclusion that so long as your voltage slew rate is approximately 1V/uS per every 1 Vrms of output, you should be just fine from slew induced distortion forms.
It was mostly John Curl and I who arbitrarily pushed this up to 40 V/uS to correspond with 1 Vpeak output for a nominally 100W/8 Ohms output (as that was my initial question), clearly stating that this was more to appease our minds than a real necessity.