[Elecraft] K3S vs. K3

[Joe Subich, W4TV]

> If I'm not mistaken, the resistors were removed a LONG time ago,
> which, when placed as they were, caused the distortion.

The resistors were changed to 51 Ohms very early on ... prior to
s/n 2000, IIRC. The transformers were changed somewhat later to a
better behaved Bourns LM-NP-1001B (same transformer used in the
microHAM interfaces).

73,

    ... Joe, W4TV


On 2015-05-16 11:53 AM, Jim Brown wrote:
> On Sat,5/16/2015 6:33 AM, Mike Harris wrote:
>> Sherwood has previously commented unfavourably on the audio quality of
>> the LINE OUT signal.  This has lead to the general acceptance that the
>> LINE OUT level should be limited to 8-10.
>
> This is pretty ancient history, and is the result of a digital guy
> trying to design an audio output stage. The error was in 1) using an
> unshielded telecom transformer and 2) adding 600 ohms in series between
> the output device and that transformer. In the world of audio, that's
> well known to cause distortion. 3) 600 ohm inputs and outputs have not
> been used in pro audio for more than 40 years, another goof.
>
> I noticed the problem as soon as I got my first K3, measured it, and
> showed it around. I don't know if that was before or after Rob found it.
>
> If I'm not mistaken, the resistors were removed a LONG time ago, which,
> when placed as they were, caused the distortion.
>
> 73, Jim K9YC
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