[ARC5] Capacitor Types

[WA5CAB--- via ARC5]

Orange drops (and the equivalent maroon ones) have radial leads and were 
designed for PC board mounting near the end of tube type TV production.  If 
the HQ-129-X is wired with PC boards, then orange drops are electrically OK 
for plate/screen/etc. decoupling and coupling other than around the RF and IF 
tubes.  Pretty much anywhere the original was paper.  As someone else said, 
it's better to use mica or ceramic there and for coupling.  If the receiver 
is wired point to point or on terminal boards, use axial lead types.  My 
preference is metalized polypropylene in 630 VDC rating (they are no larger and 
usually smaller than equivalent value 100 VDC rated ones from the 1940's 
and earlier and about the same size as 300V or 400V ones from the 1950's).

The problem with using orange drops in place of axial lead originals is 
that in most cases you have to bend the leads and convert them to axial lead 
style.  This usually results in cracking a little of the orange casing off and 
sometimes cracking the seals.  Plus, although unlikely to be an issue in 
the average ham shack, if subjected to shock and vibration, the mass isn't in 
line with the leads and the leads get twisted back and forth.

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

In a message dated 01/24/2015 10:04:19 AM Central Standard Time, 
mark.k3msb at gmail.com writes: 
> Hi Guys
> 
> I have this info squirrled away somewhere but can't find it, so I'll
> ask.....
> 
> When replacing capacitors I thought it was recommended to use mica for the
> RF sections, and for all sections downstream of the IF (towards the audio)
> to use orange drops.
> 
> Is is advisible to use mica or orange drop type caps for IF stages?  I'm
> working on an HQ-129-X and I was planning on using mica for the RF and 1st
> IF stages and my supply of orange drops for all the other stages.
> 
> I've typically just used orange drops for everything (as I have them "in
> stock"), but I'm wondering if it's better to go mica for the RF side of 
> the
> house.
> 
> Thanks!
> 
> Mark K3MSB