[Elecraft] KPA500: How to troubleshoot "distorted audio"

[Jim Hooper]

Thanks again to everyone who responded to my question about troubleshooting distorted audio on my K-Line. 

This note is to provide you feedback on what I believe to be the causal factor for the distorted audio.  

The distorted audio goes away when I remove the line-in stereo cable (a Radio Shack cable) that goes from my MBox-2 sound “card” to the K3; the MBox-2 does not need to be connected by USB to my computer for there to be audio distortion.    

I have had an MBox-2 for over 10 years and have used it for voice recording to ProTools software, though I have haven’t used it for that application for quite awhile.   Having the MBox2 available and having read Jim’s write-ups on sound cards, I thought I would give it a try fairly recently - this it the answer to the question “what changed” that led to the audio distortion.   I removed my SignaLink and inserted the MBox-2.   

I am much relieved to have found the problem.   I will need to do more research to ascertain whether the stereo audio cable or the MBox-2, in this application, is the problem area. 

At the same time, I will quickly say that I have also identified that I need to implement station bonding improvements.   

But having identified the problem and my being able to eliminate it is quite a relief.    

Again, thank you to all those of you who responded, and especially to Jim and to Jack.      

73, 
Hoop
K9QJS
San Juan Island, WA