Re: Oxygen Free Parts.

Denton, Adam (Exchange)

There was a paint "Cupra-Coat" that was basically
a conductive copper paint. If you painted all the
walls, floor, and ceiling of your lab, and grounded
the applied paint to the scope and a good Earth
ground, you should be able to vastly reduce
interference from outside the lab, which should
greatly improve viewing. Painting over any windows
is, of course, a must.

The line cord is a good idea but these are typically
stranded. You must make sure that, as you traverse
from the wall outlet to the scope, the strands twist
clockwise -- NOT counterclockwise. This is due to
the slight 'handedness' of the copper atom nuclei.
Unfortunately it's hard to tell which way they twist
without cutting the cord.

Adam :-)

-----Original Message-----
From: jbarnes []
Sent: Monday, July 21, 2003 7:50 AM
To:; tss_steve_990
Subject: Re: [TekScopes] Oxygen Free Parts.

I would also consider replacing the BNC connectors on the inputs. I think
that gold plated ones would significantly improve the "viewing experience".

Do any of the readers have experience with using oxygen free copper line
cords ?


---------- Original Message ----------------------------------
From: "tss_steve_990" <>
Date: Mon, 21 Jul 2003 02:34:49 -0000

I know that the fast, soft recovery rectifiers do reduce the
generation of RFI caused by conventional rectifiers (see Rick
Miller's article in The Audio Amateur 1/94 "Measured RFI Differences
between Rectifier Diodes in Simple Capacitor-Input Power Supplies.")
Rick's photos are from a Tektronix 2710 Spectrum Analyzer. General
Semiconductor Quick Note 108 "High Speed Rectifier Applications in
High End Audio" is another of the many published findings regarding
this subject. Here is the link for anyone interested.

I am very interested in your suggestion to use Oxygen-free copper in
the delay lines. My biggest concerned would be that the cost might
outweigh the benefit, in that one would have to have to specify and
engineer the cable dimensions and dielectrics used in order to mimic
the original cable in order to maintain the characteristic impedance
of the delay line to avoid group delay and reflections from improper
termination of the transmission line characteristics.

I believe that Tek made dark colored lenses to go in front of the CRT
to enhance contrast. My 7623A has one. I'll probably stick with
that over magic marker, but whatever lights your fire. ;-)

It has been my experience when designing and building professional
audio equipment over the years for discriminating professional
recording engineers, and in doing circuit designs and application
engineering for customers during my tenure as VP of Engineering at
Jensen Transformers, Inc. that some "Audio types" have not combined
their listening tests with good engineering. The dynamic range and
perceptual acuity of human hearing is pretty vast, however, and I
have learned that when my customers hear something amiss that I have
not found with my measurements, I am probably not measuring the right

Steve Hogan

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