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Help I need to locate a part

I have owned Spectral amps DMA 50, 80, and still own a 90.
(I find the Audio Magic digitals sound like the 80)
Spectral, when last I spoke with them would not touch something if anyone else had been in it. This was in the days when they told folks that non-MIT cables could damage the amps.
I had a chip in the 50 blow, and an ex teck named Crosby helped me locate it as he and spectral had bought out the market on that chip.
Well, my 90 is literally giving me static and my current teck needs to
replace the I.C. and we really need to locate, either:
*the chip,
*any contact info for Mr. Crosby (who might know the chip intimately) or
*someone who knows cross referencing and may know a better alternative to
a very hard to find chip.
I'm not technical when it comes to circut specs.
But this is the info on the chip:

number NPD5566.
The other number which we believe is a date code only is M9384.

So if anyone can please help me, email me any leads, I will be very
grateful.
This amp already has upgraded RCAs, binding posts, I.E.C. input and output
wire, and is sounding closer to the next version as well as nearly like
the next size up.
Thank You all in advance for any assistance you may provide.
Spiro
spiro
rodman99999
6,109 posts
 
(http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&keywords=opa627) Supposedly- these are equivalents to the 2N5566(NPD5566). I'd prefer the Burr-Brown, the data-sheet of which can be downloaded here:(http://www.datasheetcatalog.com/datasheets_pdf/O/P/A/6/OPA627.shtml)
hotsauce
108 posts
 
http://www.diyaudio.com/forums/showthread.php?postid=155479

This fellow has 230 of them to sell.

John C.
spiro OP
115 posts
 
Thanks folks.
After I posted, I tried google and found the mention of the n-ch jfet as well.
But may I ask, regarding the B.Browns, what improvement would they make in an amplifier?
Are they a straight replacement in that app to the NPD?
Also, John, C. I saw hat and couldn't get into the thread on the given link.
So thank you all.
Anyone have info on Mr. Crosby, the "Crosby Quad's" technician?
Thank you.
kirkus
502 posts
 
Rodman, your link is to an OPA627, and that's an opamp, NOT a dual JFET. They're, uh . . . different. Using it as a sub would be like trying to substitute a brake caliper for a carburetor.

These things were kinda in vogue in the early 1980s, and were used in some Urei compressor/limiters. Last time I worked on one, the 2N5566 was out of production and a pain in the butt to find -- and that was well over a decade ago. But that was also in the Internet's relative infancy, so it may actually be easier to find these days.

Subbing small-signal JFETS in a power amplifier is NOT a journeyman-technician's task . . . best left to somebody very experienced - "JFET-rolling" is a very bad idea! Small differences in junction capacitances from one type to another could at best make the amp not sound like it should, or at worst turn it into a power-oscillator, destroying both the amp and any speaker attached.

I'm still blown away that Spectral won't give factory service for your amp - that's absolutely the best option.
rodman99999
6,109 posts
 
Mr.s K & S- You'll note I prefaced my note with a, "supposedly". My brief glance at a substitution handbook at work was obviously TOO brief. Please accept my profound, "OOPS!"
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