K2 SSB audio - fuzzy around the edges

[Joseph Szczubelek]

I have a K2, mid 5000 serial number, mic input wired for Kenwood, 50 amp 12 volt Amidon power supply, with a KPA100 running 100 watts. I can easily switch my HM-10 mic between transceivers using seperate audio cables for each radio to perform on air testing. When using a Heil microphone HM-10 with dual element (HC-4 or HC-5) with Heil shielded cable and mic plug wired for Kenwood and no external pre-amp for the K2, audio setting SSBA is at 2, and compression setting SSBC is at 2-1, and asking other hams for a critical audio report I am being told that I sound a little fuzzy around the edges on the K2. I am using an Amidon type #43 toroid with seven turns of mic cable just before the mic input to the K2. Any extra Heil mic cable is coiled up as common mode choke about 5 inches in diameter. The distortion might be a little more with the wider HC-5 element. The HM-10 mic works fine and gets great audio reports on a Yaesu FT-1000D - same antennae and same
 power levels. Only when asking for an audio report does the "little distortion" report come up. I have also applied the grounded K2 mic connector mod.

Is this as good as it gets with the K2 audio ?  

Am I asking for too much for Heil HM-10 with the K2 to sound like the Yaesu FT-1000D ?

Does audio compression in the KSSB create a little distortion in the audio ?

Thanks

Joe - K9DMV    


     
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Don Wilhelm-4]

Joe,

It is difficult to say what others may perceive as "fuzzy around the edges".
May I suggest that you operate the K2 into a dummy load and listen to it
yourself on your FT-1000D.  Actually it would be better to record the
output of the FT-1000 and listen to the recording because it is
difficult ot talk and listen critically at the same time.  For best
results, adjust the antenna (usually a short wire will do) until the
signal into the receiver is about S-9.  You can use that recording
technique to evaluate the effects of various levles of compression.

The K2 audio bandwidth should be in the vicinity of 2.4kHz - I don't
know what the FT-1000 has for bandwidth.
If your audio is a bit too high or low pitched, you will find good
success by changing the filter passband position slightly.  Normally the
low frequency -3db corner of the passband should be positioned at 300 Hz
for best intelligibility.  If you use Spectrogram to measure the filter
passband placement, you can normally have good sounding audio.  If you
are not familiar with using Spectrogram to align the filters, I have
information in part 3 of the article on K2 Dial Calibration at my
website www.w3fpr.com.
Checking your OP1 filter with Spectrogram may be the best first step,
then evaluate the result.

73,
Don W3FPR

Joseph Szczubelek wrote:

> I have a K2, mid 5000 serial number, mic input wired for Kenwood, 50 amp 12 volt Amidon power supply, with a KPA100 running 100 watts. I can easily switch my HM-10 mic between transceivers using seperate audio cables for each radio to perform on air testing. When using a Heil microphone HM-10 with dual element (HC-4 or HC-5) with Heil shielded cable and mic plug wired for Kenwood and no external pre-amp for the K2, audio setting SSBA is at 2, and compression setting SSBC is at 2-1, and asking other hams for a critical audio report I am being told that I sound a little fuzzy around the edges on the K2. I am using an Amidon type #43 toroid with seven turns of mic cable just before the mic input to the K2. Any extra Heil mic cable is coiled up as common mode choke about 5 inches in diameter. The distortion might be a little more with the wider HC-5 element. The HM-10 mic works fine and gets great audio reports on a Yaesu FT-1000D - same antennae and same
>  power levels. Only when asking for an audio report does the "little distortion" report come up. I have also applied the grounded K2 mic connector mod.
>
> Is this as good as it gets with the K2 audio ?  
>
> Am I asking for too much for Heil HM-10 with the K2 to sound like the Yaesu FT-1000D ?
>
> Does audio compression in the KSSB create a little distortion in the audio ?
>
> Thanks
>
> Joe - K9DMV    
>  
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html