[Elecraft] CM 500 Ear Covers - Update

[Joe Subich, W4TV]

A follow-up ...

Since I had two pairs of CM-500 that needed refurbishment
(my original pair - without any cushions - and my current
pair - that is starting to flake), I took a chance and
ordered cushions for the Koss QZPRO.
     <https://koss.com/products/qzpro-ear-cushion>
They arrived a couple weeks ago and appear to be a perfect
fit for the CM-500.  I would guess they are the same as the
suggested UR-20 cushions (which are "Sold Out").

As the foam was also gone (original pair) or falling apart
(current pair), I started looking for a suitable replacement
as I did not want to do a cut up sock and double stick tape
as suggested in one You Tube video.  I found these:
    <https://www.amazon.com/dp/B07WN8SWHR>
These are 90 mm round and I was able to simply tuck them
between the QZPRO cushions and the face of the CM-500
"speakers" after installing the new cushions.  There was
no need to cut them down to fit the recesses of the CM-500
and hold them in place using double stick tape.  The foam
is a bit thicker and softer than the original Yamaha (Koss).

Finally, and probably not necessary, I added cloth covers ...
    <https://www.amazon.com/dp/B09B7JCY8H>
Although I took a chance and got a spare set of the cushions and
foam disks for each of my CM-500s, I decided the extra protection
from sweat, etc. was probably worthwhile for the long term.  I
went with black but a station with multiple operators could use
a different color for each operator.

All in all, replacing the cushions and adding new foam is quite
easy - no broken speaker wires if one is careful.  Getting to
the three screws (Phillips #0) is easy once one learns where
they are (front and +/- 120 degrees).  For $18 total per headset
for cushions ($5), foam disks ($9) and covers ($8 for 2 pair)
the cost is far less than an equivalent replacement headset
(the CM-500 is currently $60 on Amazon).

73,

    ... Joe, W4TV


On 5/8/2023 6:14 PM, Joe Subich, W4TV wrote:
> 
> On 5/2/2023 12:03 PM, Walter Underwood wrote:
> 
>> The Koss UR-20 is the same headphone as the Yamaha CM-500 and Koss 
>> SB-40, but without a boom mic. The link to these replacements was 
>> posted in this email reflector (11/1/19) by Josh W6XU. These are the 
>> ones I ordered. 
> 
> Unfortunately, the SB-40 ear cushions are "Sold Out" at Koss.  The 
> QZPRRO headset ear cups appeared to be the same size/shape so I
> ordered a couple pairs (both of my CM-500s need new cushions) and
> they fit just fine: <https://koss.com/products/qzpro-ear-cushion>
> The foam in both of my headsets has also deteriorated but the QZPRO
> cushions do not come with replacement foam.  My next step is to find
> a source for that foam.
> 
> For the benefit of others, the earphone cups of the CM-500 are
> 98.4 mm (3 7/8") x 93.6 (3 11/16") - a standard 100 or 105 mm
> (round) headphone pad should work.  However, since the screws
> holding the headphones together are located under the cushions and
> the cushions are clamped between the face and cup of the headphones,
> cushions with built in foam screens will not work.
> 
> The foam screens are 80 mm (3 1/8") x 60 mm (2 3/8") and are
> fixed to the face of the headphone with double stick tape.  One
> could probably use 98 x 93 mm foam and simply slide it between
> the earpad and the face of the headphone after the earpad has
> been replaced.
> 
> 73,
> 
>     ... Joe, W4TV
> 
> 
> 
> On 5/2/2023 12:03 PM, Walter Underwood wrote:
>> Replacement ear pads are available, but the internal wiring is very 
>> fragile.
>>
>> I managed to get the replacements on, but broke a wire. After four 
>> breaks and three re-solderings, there wasn’t enough wire left to work 
>> with, so I bought a new headset.
>>
>> The Koss UR-20 is the same headphone as the Yamaha CM-500 and Koss 
>> SB-40, but without a boom mic. The link to these replacements was 
>> posted in this email reflector (11/1/19) by Josh W6XU. These are the 
>> ones I ordered.
>>
>> https://www.koss.com/accessories/cushions/ur20-ear-cushion
>>
>> This video walks you through the replacement steps.
>>
>> https://www.youtube.com/watch?v=Gz-atFziEz4
>>
>> This guy just glued on the new ones, which might be a safer approach.
>>
>> http://n4cf.mdodd.com/cm500_pads.html
>>
>> wunder
>> K6WRU
>> Walter Underwood
>> CM87wj
>> http://observer.wunderwood.org/ (my blog)
>>
>>> On May 2, 2023, at 7:24 AM, Paul Ecker <eckerpw at gmail.com> wrote:
>>>
>>> Realize this subject has been around before, most of postings in 
>>> archives
>>> are dated. Does anyone have a good current source for replacement ear
>>> covers for the Yamaha CM 500 Headset?
>>>
>>> 73 Paul w2eck