> We used my K3 on the running station and a Icom IC-7700 on the multiplier > station. This was actually the first time I could compare the K3 to a high > end transceiver such as the IC-7700. I was surprised to find out that the > 7700 sounded much better.
Maarten, At my station, the K3, '7700, and '7800 are side-by-side. Of all three transceivers, the K3 produces the least amount of residual hiss. In fact. when the AF control is turned full CCW on the Icom's, a slight degree of hiss remains. Zero hiss with the K3. If you look at the audio structure of the K3's headphone circuit, it would be pretty difficult to improve upon when using a single-ended power supply. When bi-polar power supplies are used, it's possible to eliminate intra-stage coupling capacitors with servo-controlled op-amps, thereby eliminating DC offsets. Larger voltage swings are possible with bi-polar supplies and overall distortions are generally lower with these circuits. You tend to find these techniques used in Hi-Fi audio and broadcast equipment, but not in communications-grade audio systems. One important point is that the stock K3 has less low-end audio response than that of the two Icoms. But that's a personal choice. Some well-respected ops here detest the presence of low-end audio below ~ 200 Hz. Others (myself included), like to hear the entire passband while operating -- right down to 50 Hz or so. It's not right, it's not wrong - it's just a personal preference one way or the other. My personal choice is to open up the audio response, then limit low-end and high-end response through the K3's DSP filtering. I get the best of both worlds that way... In order to attain a richer low-end response on the K3, you may wish to review my mods on the N1EU website. After modification, the K3 is capable of sounding just as rich and smooth as the two Icoms. My guess is that when you use the adjective "sharp," you're likely hearing a lack of low-end balance as both transceivers are capable of extremely sharp low-pass response. If you do invoke the mods, I would suggest first looking at the revision of your Main DSP Board as some of components I've changed may have now gone into production at Elecraft. It may also turn out that Elecraft eventually scales the audio R values rather than C values to accomplish the same end result. I changed C values since fewer components are changed that way. Paul, W9AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
