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Old 16th April 2007, 04:23 PM   #1
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Default bora's legend 4 consideartions

i am sakis petropoulos and yes amplifier legend 4 and 8 was given to me from dr Bora for free and also given as request to operate in voltage from 56 to 66 vdc per rail

well this amplifier is working perfectly in voltage 40+40 volts but no matter how much i tried so far to operate at 66+66 volts i end up with burned mosfets burned speakers and a lot of smoke

i have grate respect for dr BORA and also his designes i am extremelly thankfull cause he gave this for free to me and also willing to help and suport me with alot of suport
enenthough we all very well know that he is in a difficult moment of his life ......

to my understanding maybe dr Bra missed that my rails are 66+66 volts and may be many things need to be chanched to operate at this voltage ....thats ok he done a lot so far and i know very well that may be he canot do more at the time so i asked help from all you forum guys and seems that after a long time i am getting somewhere .....


also didnt know that dr Bora was sick so i made posts saying that probably dr Bora didnt help me out i could neverthink that he might be in a hospital

I APOLOGIZE FOR THAT ......

but otherwise i never altered or chanched any of my request or the amplifier spece

sakis petropoulos
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Old 16th April 2007, 08:42 PM   #2
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Hi,

Check this thread with my comments on that "+/-66V" design:
look at this schematic

PS.: Only for accuracy. The genuine design that you call "Legend" isn't Bora's work, but Nelson Pass's. Called "Citation 12", published in the Audio Amateur magazine in the early 80's. Bora only added some tiny modification.
http://www.passdiy.com/pdf/citation.pdf

Cheers,
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Old 22nd May 2010, 08:57 AM   #3
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Quote:
Originally Posted by sixtek View Post
Hi,

Check this thread with my comments on that "+/-66V" design:
look at this schematic - diyAudio

PS.: Only for accuracy. The genuine design that you call "Legend" isn't Bora's work, but Nelson Pass's. Called "Citation 12", published in the Audio Amateur magazine in the early 80's. Bora only added some tiny modification.
http://www.passdiy.com/pdf/citation.pdf

Cheers,
On the end there is complementary version of "Citation 12"
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Old 22nd May 2010, 10:12 AM   #4
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there is no point on bringing back to life this project ... Many things have been said about it and i am not sure if all of them is correct

Remains a fact as said above that DR BORA published this for free but somewhere on the way there was some mistake by me or DR BORA regarding the rail voltage and seems that this circuit as was it wasnt possible to operate properly in this rail voltage

we have to thank DR BORA once more for his efforts his designs and personal time that devotes in the diy community

Other than that all the legend 4 i built with 40+40 rails work perfectly ....with the only adition of an inductor in the output

kind regards sakis
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Old 22nd May 2010, 10:31 AM   #5
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Post is for "sixtek" about evolution "Citation 12"
http://www.passdiy.com/pdf/citation.pdf
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Old 22nd May 2010, 10:45 AM   #6
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i am sorry to say that sixtek hasnt been arround the forum for very long time ...almost 3years ... me , and other forum members wonder about his where abouts and fear for his health

let us all hope that at least he is allright /

regards sakis
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Old 24th May 2010, 08:33 PM   #7
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Regarding my LEGEND design, I will try once and forever to explain some things.
Legend was designed in Belgrade in early summer 1979 and it was quite famous in the (then relatively narrow) audiophile circles. Some prominent designers and audiophiles like Mr.Mirko Voznjak and Mr.Dragan Milanovic (AKA Djura Imperial) and Mr.Zoran Radetic and Mr Felbab Novak and Mr.Viktor Bradac as well as some other but they don't mean anything to any of you. At that time access to the world literature was generally very limited in my and similar countries, and just a very few people occasionally provided some issues of Elector (German), Audio (USA), Haut-Parleur (Fra.), Radio (USSR), Wireless World … well that’s about all. For a man named Nelson Pass I did not know, and the first contact with that name was almost 6-7 years later in one number of Audio magazines that has been brought from America by young audiophile from one Belgrade suburb. His parents were diplomats that came back to BGD from abroad. I was almost in disbelieve when I saw that article about mods and improvements of then very esteemed Harman Kardon amplifier done by some Nelson Pass. Only a few minor details distinguish it from my design Legend. Outputs were then exotic FET's and mine had a classical BJT an RCA 40636. At that time MOSFET's were the "abstract noun" here in my part of the world! Back then we were supplied mainly from Germany: RadioRIM, Conrad, Holzinger-Strixner, HANSA electronics, Opperman etc. Only much later, I modify LEGEND to have MOSFET's as in Mr. Pass's approach, but that was when they have become more available and at reasonable price.
So what was the trick? Simply, the concept of the mentioned HK amplifier Citation12 was then “in fashion” and represents one of the generic topologies known as Linn's topology. At that time many people all over the world (including ME) based their designs around this topology just as would later happen with all subsequent modern topologies. It certainly can’t be seen as theft or plagiarism. Simply, it is logical and very possible that different people come to very similar or almost identical solutions if they properly apply the rules and calculations.

Believes that only designs that doesn’t looks like any other are acceptable as an original... is so wrong!

All petrol engines in today's cars are based on a generic engine designed by Daimler&Benz, and Renault, Fiat, GM, Toyota and Mercedes and all other manufacturers will consider their models as their designs, and would certainly not feel like copycats or fraudsters because their engines also have spark plugs, pistons and the crankshaft and camshaft and carburetor and. ... just as Daimler-Benc generic engine model has!
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