K3: switching on click -- One wonders...

[Edward R Cole]

First off, I am not using an amplified speaker; it is a National
Receiver speaker from circa 1950's.  I have used it with my FT-847
for years before getting the K3 (#4340) in 2010.  Never popped like
the K3.  In fact none of the ham radios that I have owned since my
first one in 1958 ever did this (so much for your theory this is common).

Its not a thump on my K3, it is a sharp POP.  Sometimes a double
POP-POP.  You can duplicate what is sounds like by applying 24vdc,
momentarily, to any common 4 or 8-ohm speaker.  If it doesn't destroy
the speaker coil in the process it will give you a very loud sharp
pop!  The internal speaker also pops at start up.  In the headphones
it is also there but not as loud.  Audio gain control has no effect on it.

My home theater 200w receiver does have a low thump in the speaker
when turned on, but not a sharp pop, and not as loud.

I haven't mentioned this until this thread came up, but I was
certainly alarmed the first time I turned on the radio.  MY power
supply is a 50amp Astron analog supply - if that matters.  Again
neither the FT-847 or FT-817 exhibit any sound when turned on except
radio noise and/or signals.

Some have suggested turning off the speaker.  Well, that is kind of
hard since the mini-phone plug has wires directly to the speaker
coil.  Again it is a plain speaker - no amplifiers.

The only way for me to mute the radio is to make a 555 timer to
control a relay to disconnect the speaker during start up.  But that
will not silence the snap at shut down.  I guess if it irritates me
enough I can mount a switch on the speaker to disconnect it
(providing I remember every time I turn on/off the radio).

This is all I am going to say on the subject.  I will leave it in
Elecraft hands at this point.

Ed - KL7UW

----------------------------------------
Message: 18
Date: Sun, 4 Sep 2011 14:16:46 -1000
From: David Herring <[hidden email]>
Subject: Re: [Elecraft] K3: switching on click -- One wonders...
To: Elecraft Reflector <[hidden email]>
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=us-ascii

Hi All!

I know we've milked this one quite a bit, but I do have a point to
make that I think will frame this "power-on thump" issue in a little
better light...

First off, I have K3 #3019 and there is a very detectable power-on
AND power-off thump in the built-in speaker and in the cans.  I don't
have external speakers so I can't say about that.

BUT, what I wanted to point out is that this behavior, this power-on
and power-off click or thump is widespread and not strictly a K3
problem.  While there are others on this list with way more
experience in the field of audio, I can say that in my younger days I
was very much an audiophile.  I can tell you with certainty that all
the high end audio equipment I owned (and wished I owned!) thumped
when powering on and powering off.

Outside of my own equipment, I have worked mixing boards and
commercial sound systems which all thumped on power-on/off.  Some
loud enough to nearly blow your hair off.

I have even witnessed this in concert halls -- I'm thinking, as one
example, of the Pacific Amphitheater one night in LA which very
clearly had the power-on/off thump.  I can think of others probably
if I worked my brain cell really hard.

The point is that this phenomenon seems to be part and parcel of the
powering-on and powering-off of solid state audio amplification.  As
this exists in the high quality and commercial equipment I've had the
pleasure of working with, I don't feel it detracts from the K3.  I
think the K3 is actually in pretty good company.

I know that being common doesn't make it right...but it probably does
indicate that most in the business don't regard it as particularly important.

IMHO if it costs more than a nickel to fix, I wouldn't
bother.  However I understand that others, perhaps with amplified
speakers, are well within their rights to feel differently.  :-)

Alrighty then...back to the honey-do list...

73 & Aloha,
Dave  AH6TD




73, Ed - KL7UW, WD2XSH/45
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