[Elecraft] CM 500 Ear Covers

[Joe Subich, W4TV]

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