[Elecraft] [K3] Audio circuit distortion

[Wayne Burdick]

 Don Putnick <don.na6z at earthlink.net> wrote:

> I watched the presentation again. Yes, Rob said the K3 was fixed in 2008. He also said the fix wasn't as good as he'd like. It didn't compete with the <0.3% distortion of the Icom 756 Pro III. So if you look at the distortion products at 44:20, would the average amateur (like me) be able to hear that?

Short answer: No. 

I have excellent hearing (I'm an acoustic guitarist and pianist in my "spare time"), and after we made all the updates to the K3, I burned quite a bit of lab time trying to hear what Rob was talking about.  I tried *really* hard, as did my staff. We couldn't hear it. Rob is superhuman :)

True, it would be possible to reclaim a bit of extra AF headroom by using an AF amp that's heavily biased (class A). But 99% of operators would not benefit, the radio would draw an extra 200-300 mA with no signal in receive mode, and the chip(s) would need fairly extensive heat sinking. Doesn't seem like a good tradeoff. 

(Disclaimer: I'm biased towards energy efficiency and portability.)

Wayne
N6KR