[CQ-Contest] Heil vs. KOSS

Roderick M. Fitz-Randolph w5hvv at aeneas.net
Mon May 11 21:18:38 EDT 1998

I have recently purchased the KOSS made Optimus PRO-50MX Stereo
Headphones with boom microphone from Radio Shack while still on
sale for the price of $29.95, I believe.

I was shocked to find that, to my decadent ears, the 10-22,000
Hertz reponse of the KOSS made PRO-50MX was vastly superior in
my being able to hear clearly all of the speech I listened to on
SSB on 20, 40, and 80 meters.  This was in comparison to my Heil
headset with boom mic that I won at the DX Banquet two years ago
as a door prize.

Up until now, I had been quite pleased with the Heil headset.  I
thought perhaps my hearing was simply going the way of all life
as time progresses....fading away.  But... when I put on the
Optimus PRO-50MX set I was astounded to hear the difference.  I
had long thought that the ultimate clarity of sound assisted
intelligence transfer and now I am sure.

I tried several times, with both headsets plugged in simultaneously,
(one is a 1/8" plug and the other is a 1/4" plug so that they fit
the 1/8" and 1/4" phone jacks on my FT-1000MP at the same time.

I pulled one out and reintroduced it while listening to the opposite
headset several times and with each headset until I was satified that
there was no detectable difference, whatever, in the volume or
frequency response (which, incidentally sure does make it nice for
two people to listen at one time while trying to decipher some badly
QRMed station trying to ID for you:).

With both sets plugged in and going from one to the other on the same
conversation, there was no doubt as to whether or not I could hear
more clearly and distinctly the spoken words.  The high frequency
response was better giving sibilence more emphasis, while the low
frequency response seemed to give better depth to the spoken words.
All in all, I was highly impressed.

The KOSS PRO-50MX Stereo Headphones with Boom Microphone has a very
good microphone element in it but it can't match the Heil Dream Machine
HC-4, or (in my opinion) HC-5 but there would be those that would argue
the point on the HC-5 element, I'm sure.

THE BIG PAYOFF is that the rectangular clamshells that fit around the

All that is necessary to turn these into a superior contesting and DXing
headset with boom microphone is to order the clamshell plastic boom end
that fits on the Heil boom mics along with the Heil mic element (your
choice.... either the HC-4 or HC5) and assemble it... and you have a
very fine set.

Incidentally, the boom is flexible enough to allow use as a right handed
mic or a left handed mic.  It rotates right up and over on the other side
for opposite mic positioning!!!

One word of caution: read closely the instructions that come with the
Heil mic element about not exceeding a 1 second heating time of the two
pads where small wire connects to the element.... Also, attach a 3/4"
extension of that small wire to the mic element and then solder the
other end of the extension to the wires supplied in the PRO-50MX boom.
Otherwise it won't quite reach and you run the risk of damaging the
mic element while trying to attach the fine wires to it.

Anyhoooo, I going back to Radio Shack and buy another one of those!
They are great!

Rod, N5HV
w5hvv at aeneas.net

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