[Elecraft] K3s Internal Speaker

[Don Wilhelm]

Mike,

That warning dates back to the early days of the K2.  Originally no 
fiber washers were provided, and several builders tightened the screws 
excessively and deformed the speaker frame.  That warning has been 
present in manuals calling for mounting the speaker ever since.
The screws should be tightened securely, but not "beefed down" such as 
to squeeze the fiber washers enough to deform them - and that will 
deform the speaker frame.

Like Wayne, I have not heard of this problem with the K3 or the K3S and 
have not heard of similar problems with the K2 after the fiber washers 
were introduced.  There is an occasional bad speaker encountered, so I 
would tend to believe this is a "one-off" case of a bad speaker.

There *are* two different thicknesses of fiber washers used in Elecraft 
kits.  The thinner ones are used on the K2 PA mounting hardware, and the 
thicker ones are used for mounting the speakers. Perhaps Steve was sent 
the thinner fiber washers with his kit (that is only a guess on my part).

73,
Don W3FPR

On 12/5/2015 4:35 PM, ac5p at sbcglobal.net wrote:
> I have an older K3 and a spare speaker (part #E850300).  Its hard to imagine flange being bent with little 4-40 screws, BUT, in my assembly manual p52, last step above Figure 74,it states in BOLD lettering, "Do not tighten the screws enough to bend the speaker flanges!"
> IF this were not an issue sometime in the past,  one wonders why such a warning would be stated in bold letters?     Otherwise I find the little speaker to be as Wayne describes in his reply.   Steve could you really be the first out of so many thousands to actually bend the flanges?
> 73,MikeAC5P
>
>
>      On Saturday, December 5, 2015 2:11 PM, Wayne Burdick <n6kr at elecraft.com> wrote:
>   
>
>   Hi Steve,
>
> Sorry to hear about this. I've never heard this complaint before (and there are tens of thousands of these speakers in use, in both the K3 and K3S). The frame should not bend if the correct fibre washers are used and the hardware is not over-tightened. I'll check with our manufacturing lead to see if the wrong ones were shipped.
>
> I'll also check with our tech writer. Perhaps the instructions could be clarified.
>
> The internal speaker is certainly of high quality, so I hope you can get one installed (I'm sure customer support will send another, given your issues). It has excellent sensitivity (95 dB SPL, due in part to the very large shielded magnet) and a wide frequency response range. Given the large top cover mounting surface, the internal speaker is quite loud, with a low natural resonance point.
>
> 73,
> Wayne
> N6KR
>
>