[Elecraft] [K3] in-band-IMD test

[Joe Subich, W4TV]

> This is an issue with the isolation transformers in the LINE 
> OUT ports.  I've measured similar levels, and shown how they 
> might be reduced. 
> http://www.cliftonlaboratories.com/elecraft_k3_receive_audio.htm

Elecraft have changed the series resistors from 604 to 50 Ohms 
in current production.  See the October schematic updates on 
their web site. 

I'm assuming a change in the schematics indicates the modification 
is now "approved." 


73, 

   ... Joe, W4TV 
 


> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jack Smith
> Sent: Wednesday, November 12, 2008 4:24 PM
> To: Alexander Ponomarenko; 'Elecraft'
> Subject: Re: [Elecraft] [K3] in-band-IMD test
> 
> 
> Alex:
> 
> This is an issue with the isolation transformers in the LINE 
> OUT ports. 
> I've measured similar levels, and shown how they might be 
> reduced. 
> http://www.cliftonlaboratories.com/elecraft_k3_receive_audio.htm
> 
> You will not see  the same degree of distortion on the 
> headphone output 
> port.
> 
> Jack K8ZOA
> 
> 
> Alexander Ponomarenko wrote:
> > GA for all K3 users.
> > So many guys has talks about perfect audio sound of K3.
> > So many talks about "analog K3 sound" on e-ham.
> > But how it possible if K3 have the so bad in-band IMD?
> > You can read about "in-band-IMD-measurements" in russian here: 
> > 
> http://forum.cqham.ru/viewtopic.php?t=17119&postdays=0&postorder=asc&&
> > start=0
> >
> > Or you can simply look on the pictures, where is in-band
> > IMD-measurements of
> > SDR-5000, IC-7800, IC-756pro2 and K3 - so bad for HI-FI sound 
> > announced by many K3-users:
> > it's for S9-level http://forum.cqham.ru/download.php?id=31966
> > and it's for S9+50 level http://forum.cqham.ru/download.php?id=32004
> > and even measurements of S/S+N-rate is poor: 
> > http://forum.cqham.ru/download.php?id=32003
> >
> > Alex de UR5LAM
> > RU-QRP-C#103
> > K3/100F #0568