[Elecraft] (OT) Follow-up on CW Resonant Speaker

[efortner]

Stan,

I have built three of the resonant speakers per the QST article. I am using a K3s and have plenty of audio without an amplifier. The three speakers were all in the ballpark of 700 Hz. I took a 2 inch coupling and put on the street elbow and it resonates at about 500 hz. There might be slightly more audio coming out of the external speaker but when the resonant speaker is switched on the noise level drops enough to be noticeable so the project was worthwhile.

Earl, K4KAY

-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of stan levandowski
Sent: Monday, February 13, 2017 7:49 PM
To: Elecraft at mailman.qth.net
Subject: [Elecraft] (OT) Follow-up on CW Resonant Speaker

Folks, I posted about having built the CW Resonant Speaker in the February 2017 and having problems with low audio.  This is a follow-up report for those with interest in this subject.

It works!  It's fabulous!  It's unbelievable how great it sounds! CW pops out and background noise is significantly reduced.


I built it EXACTLY as described in the article and ordered the EXACT 
parts listed.  My problem was not enough audio coming from either my KX1 
or my KX2 headphone jacks.  


I purchased a fully assembled 15 watt mono amplifier - Qianson TDA2030A 
15W Mono Channel Audio Power Amplifier Board AC/DC 12V AMP Module - 
Amazon for $11.80.


With the new amp, my speaker is acoustically resonant at 760 Hz and I 
have plenty of volume; enough to fill the room.  The author had claimed 
"around 700 Hz" so it's in the ballpark.  I can verify that the 
construction article was accurate.


I wanted 600 Hz so I built a vinyl sleeve to insert into the street 
elbow and set my sidetone pitch for 600 Hz then slid the sleeve up and 
down until I got a very obvious peak in volume.


I'm still a "can fan" for serious CW operating, but it's nice to be able 
to listen to sweet CW that pops right out now that the higher frequency 
sounds are substantially subdued.


This was a really worthwhile little project.


73, Stan WB2LQF
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to efortner at ctc.net