[Elecraft] K3 Speaker buzz - But which external speaker ?

[Joe Subich, W4TV]

> You originally replied that the COMspkr wouldn't work any better than
> the internal speaker,

I have been referring to the internal *AMPLIFIER* - if I typed speaker
it was in error.

> Or, one can simply choose to pay an extra $20-$30 and bypass all of
> the fooling around by trying to find the right combination and just
> buy something that others have proven that works.

Yup, that means a pair of MFJ or Jetstream communications speakers at
$20-$30 for the pair vs. an overpriced $10 amplified computer speakers
for $40.

> My own experience is that I tried a bunch of external speakers with
> the K3 and the results sucked - in fact they were worse than other
> Icom and Yaesu rigs sitting on the bench at the same time using the
> same speakers.

Sure, if you used low efficiency speakers - like those in the Yaesu
or Icom external speakers - they will sound better with the 5 - 10W
amplifiers in the Icom/Yaesu rigs.

73,

    ... Joe, W4TV


On 11/7/2012 2:50 AM, Tim Tucker wrote:
> Or, one can simply choose to pay an extra $20-$30 and bypass all of the
> fooling around by trying to find the right combination and just buy
> something that others have proven that works.  Sacrificing the Line Out for
> external speakers is a pretty lousy solution, IMO.
>
> You originally replied that the COMspkr wouldn't work any better than the
> internal speaker, however I know from personal experience that it does
> exactly that.  Take off your engineer hat and put on your consumer hat.
> For some of us, spending an extra couple of bucks to just be done with the
> whole problem (that shouldn't exist in the first place) is worth it.  I
> don't need or want to go execute an algorithm to figure out which speaker
> will allow me to hear the rig at an acceptable volume.  If you like doing
> that, no one is going to criticize you, however, not all of us feel like
> going through that exercise.
>
> My own experience is that I tried a bunch of external speakers with the K3
> and the results sucked - in fact they were worse than other Icom and Yaesu
> rigs sitting on the bench at the same time using the same speakers.  I got
> tired of fooling around with it and decided to purchase the powered COMspkr
> and was satisfied. Are there better solutions?  Perhaps.  Do I care?  No.
> My problem is solved and I spend time enjoying the radio instead of cursing
> at the volume output of the K3.
>
>
>
>> *IF* one feels the need for an external amplifier, bypass the internal
>> amplifier by using the Line Out and high cut filter to drive a better
>> amplifier - something capable of 10W per channel at 0.01% THD instead
>> of 3W per channel at 1% THD like the COMSpkr.  Alternatively, set up
>> the external amplifier with a 16 - 32 Ohm input impedance, set the K3
>> to low AF gain to keep the LM4950 in the cleanest part of its design
>> range and use the external amplifier to provide the power gain.
>>
>> Just like RF power amplifiers, audio amplifiers are all about selecting
>> the right devices, using proper design and bypassing, then matching to
>> the right load.
>>
>
>
>
> On Tue, Nov 6, 2012 at 10:31 PM, Joe Subich, W4TV <lists at subich.com> wrote:
>
>> *IF* one feels the need for an external amplifier, bypass the internal
>> amplifier by using the Line Out and high cut filter to drive a better
>> amplifier - something capable of 10W per channel at 0.01% THD instead
>> of 3W per channel at 1% THD like the COMSpkr.  Alternatively, set up
>> the external amplifier with a 16 - 32 Ohm input impedance, set the K3
>> to low AF gain to keep the LM4950 in the cleanest part of its design
>> range and use the external amplifier to provide the power gain.
>>
>> Just like RF power amplifiers, audio amplifiers are all about selecting
>> the right devices, using proper design and bypassing, then matching to
>> the right load.  An audio amplifier needs to be able to source enough
>> current to drive the speaker without saturation or clipping.  The audio
>> chip used in COMspkr and other 3W per channel computer speakers is
>> simply no better or cleaner than the LM4950 used in the K3 - they all
>> show high THD when operated at maximum output level because they just
>> can not source the current without driving the outputs into saturation.
>> That is nothing more or less than simple physics.
>>
>
>
>