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In Reply to: RE: FULTON 's " Footlocker " Amplifier ... Finally Revealed posted by drlowmu on April 24, 2016 at 18:36:57
I recall being at Gordon Holt's when Bob showed up with the foot locker with Fulton Goldcables coming out of holes in the locker. I can't recall my reaction to the sound.
I've always felt that Bob was one of those special people who could make a silk purse out of a sow's ear. His stuff always did great justice to the music and the parts he used to build his speakers looked like they only belonged it white box speakers.
If I recall correctly the problem with the Luxman amps was the difference inAC voltage in Japan and the US. It was just enough higher here to over drive the tubes and wear them out quickly.
Follow Ups:
I have owned several pair of 3045s (still have a pair). The problem was simply too much idle current. The amps had a plate voltage close to 500 VDC and the recommended bias setting was 75 milli-amps for an idle plate dissipation of 37.5 watts! The tubes wore out from too much heat. Plain and simple. I biased my amps at 50 milli-amps (25 watts dissipation) and the tubes lasted much longer.
What ever the reason, that kind of design is inexcuseable. There's no reason tubes can't last a very long time. It just takes good design and understanding the tubes one is working with. Tube designs that constantly need new tubes are poor designs. The prototype Berning BA150 was turned on in 1972 and turned off in 1977 with no measureable wear on the tubes.
The real problem was the Luxman MB-3045's original design - that the young engineer, Tim, did not run the tubes conservatively to start with.THAT, I know today, is simply NOT good engineering.
Now a days, my " second " audio mentor ( Bob was my first ) has taught me to run tubes at Golden Ratio proportions of their maximum plate dissipations, ( 62% ) and the tubes last, almost " forever" and actually SOUND less stressed also, as a bonus to boot. Live and learn !!
So, as a modern example, my DIY 2015-designed and built Type 45 SET amp dissipates 6.2 Watts from a 10 Watt rated plate. Perfect.
Yes, Robert Fulton was gifted, and a gentleman - a born-again Christian who walked the walk. Robert was 19 years older than I, and like a father-figure to me. I loved him, miss him, but he remains in my heart.
His speakers' 1.6 mHY inductors were called " wroinkers " because they were the coils from Packard cars, starting motors, which were "dumped" by Packard when they went from 6 to 12 Volt systems. The " wroinker " was the sound of the car, when starting with a 6 volt system in the cold Minnesota winter !! :-).
Fun in Minneapolis, at the FMI speaker factory.
BTW, HaHax, we two share a mutual friend, MZ.
Jeff Medwin
Edits: 04/24/16 04/24/16 04/24/16
Two great guys, Bob and MZ. Both offered tons to audio and both were under appreciated.
Jeff, Are you serious about the footlocker amp? I was told it was a 430?!
hmmm why the misdirection's?....
we also knew from our friend Mr Fulton liked the AR D150 tube amp but never knew of this luxman amp...strange
I happen to have a friend Frank who was closer to Fred Devere then Robert and never mentioned it was always a 430 in that foot locker
now the question is where did you acquire your information?? did you always know??
Thanks Jeff
Lawrence
HK 430, NOPE !!
Found out directly from Fulton's VP, Bob Fredere, who has direct experience and also has been MIA for three decades. We only found out this month. We never knew !!
Jeff Medwin
Holy cow!! maybe we could talk about it offline?
Lawrence
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