On 1/2/2011 8:05 AM, Joe Roberts wrote:
On 1/2/2011 2:20 AM, Dr. Gerald N. Johnson wrote:
Mouser carries Vishay-Sprague Atoms. They seem to be the same high
quality they originally were. Much larger for better heat dissipation
than the miniatures too.
I believe they are now a big can with a little cap tucked inside. I use
them in guitar amps, which is probably their biggest market. They are
now super light for the size...used to be they felt like a battery!
Could be. Still the last I checked their ripple current ratings were
greater than the super compact electrolytics.
Nichicon and Chemi-Con make much better HV caps (long life, low
impedance) but they are going to be small radials, not big chunky axials
that look right and fit vintage tag strip layouts.
Best grades of axials today might be the ones made by Vishay/BC
Components with the blue transparent wrapper (used to be Philips)
http://www.vishay.com/capacitors/aluminum/aluminum-axial/
No idea where to get the high grade versions in small quantities from a
distributor. You also have to watch the size with axials...the ones TT
used in Tritons and Omni Cs were miniaturized even by today's norm.
I hadn't considered drilling new holes in the board to use radial caps,
but I think I'd be inclined to have spliced one of the leads on a radial
cap so it could routed to the original holes.
That was my inclination also. Radial leads will usually span the axial
holes. However, providing appropriate holes for radials looks better and
is more mechanically stable. I had visions of shorts when installing
radials with 2 or 3mm spacing with long unsecured leads. The leads are
mighty close together on a 1uf radial cap.
Yes.
Also, a long lead could have more reactance at/above 30mHz than the
capacitor itself. Many of these modern digital-ready caps, like Os-Cons
and motherboard caps, are very low Z well into the VHF range. A 1/2"
lead would be significant in this regard, degrading the performance of
the cap.
True, though the elderly electrolytics were not a great benefit for RF
or even IF bypassing so lead length wasn't considered in the design.
Plus, in about 30% of the cases, I could find a shorter path to ground
with a new hole, further shortening the leads. It might not matter all
that much, but the performance boost is free!
Joe N5KAT
73, Jerry, K0CQ
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