On Tue, 18 Dec 2007 13:52:17 -0800 (PST), cj
wrote:

Hi,
I got many great replies to my original post,
http://groups.google.com/group/sci.e...849027dfe5878/

With work getting in the way, I have been a bit slow at ordering and
replacing the caps in my AR 91s speakers (25 yrs old). I hope to find
some time over the holidays.

Reviewing other threads on the subject of, and talking to a couple of
friends in the my IT dept, industry, I have a few more questions
before ordering parts.

Should I replace the resistors? The speakers function, and measuring
the resistors with a multi-meter find them within tolerance. Any
other
tests I can perform? The resistors and caps leads are twisted and
soldered together, so I have to "remove" them anyway.

I was thinking about use a connector bar, screw or solder type,
versus
twisting and soldering the component wires together. Any comments on
that idea?

From lurking in this forum, I know that most of you that reply to
posts do not believe in high-end "snake oil" caps. Humor me, or go
enjoy a glass of egg-nog. Reading other forums, people recommend
using
a quality cap in parallel with a smaller value "snake oil" cap. The
result is supposedly better sound, without spending big $$. This
doesn't quite make sense to me, since a larger value cap will roll
off
at a lower frequency and thus a larger portion of the signal (for a
mid or high speaker) will be flowing through it. Is this a correct
assessment or is my "basic" understanding of caps or electronics
insufficient to understand why this recommendation has merit.


Cheers!
Christopher

Looking at the AR91 schematic here
http://www.classicspeakerpages.net/l...schematic.html
I notice that the original caps are all non-polarised electros. While
changing to film type caps (mylar MKT or polypropylene MKP) is thought
by many to improve the sound quality, this may prove to be a moot
point in reality. Those 24 uF and 40uF caps will take several
paralleled MKT's or MKP's to get the right value and the cost won't be
all that small. As suggested by William you might care to modify one
unit and compare it with a standard x-over. Listening test will
require a suitable speaker switchover arrangement.