[NJARC] Bumble Bees

[Mbeeferman at cs.com]

In a message dated 10/16/2007 5:57:29 PM Pacific Daylight Time, 
jr6v6gt at yahoo.com writes: 
> Hi Ray,
> 
> If it works, DON'T TOUCH IT! And in the case of your
> Marantz, you would be hurting its collector value.
> 
> In all fairness to Bumble Bees (or more accurately,
> Sprague Black Beauties, including those with writing
> on them)
> Marv Beeferman's *excellent* article some months back
> showed how the early versions had a "filler tube" on
> one end, which looked more like a "blob" in some
> cases. These are the REALLY bad ones. The later
> version used an improved manufacturing process and NO
> filler tube (or "blob") at one end. These are better
> -- but how much better is, of course, subject to
> debate.
> 
> I think the better ones were already available by
> 1963, so I think you're OK!
> 
> JR
> --- Facivana at aol.com wrote:
> 
> >Visit our web site - See http://www.njarc.org
> >_______________________________________________
> >   hello JR and all radio addicts
> >
> >      In 1963 I purchased a Marantz 7 preamp with 6-
> >12ax7 tubes which I have 
> >replaced 1 since I have the preamp. It is scareing
> >me to death to hear about 
> >the Bumble Caps, this Marantz is infested with them
> >. But  the preamp plays as 
> >well as any preamp at any price range.  I would not
> >touch the caps with a ten 
> >foot pole.The preamp sells for 2k and up on epay
> >check them out. The preamp is 
> >built like a tank. I once went to the marantz plant
> >and the assemly line was 
> >a mere 12 people working. It was in L.I.C  N.Y.     
> >  RAY KC2PTS Audio 
> >Fanatic.
Good advice.  Non-electrolytics made after the 60's should NOT be 
automatically shunned.  Problems arise only if they've been sitting in the de-energized 
amp (not NOS) for a long period of time.  Caps love to be continuously 
energized!  Key is application, application, application.  1) If the Engineer knew his 
business and maintained a 25% derate margin, and 2) the application is one in 
which the capacitor is not stressed (large signal and voltage swings),... 
these caps can hold their specs for more years than you could imagine.  I have 
tested GE caps installed in the mid-60's in my plant where the tolerance 
measures +/-5% for a +/-20% spec and the leakage is hardly measurable.