Re: [Elecraft] K2 / K3 audio - and the K2 fan
The issue could be due to 2 factors: AF distortion and AGC properties. K2 has a very sweet AGC. K3 had a very high AF distortion level that was mitigated by a series of upgrades ( at least choke and DSP board). If you read old messages, there is a message by a Russian who looked at initial IMD level (very high) and documented improvements by adding large capacitors in several places. If you bother to put most transceivers - particularly older rigs with analog IF and product detector - on an audio spectrum analyzer and feed them a source of broadband RF noise you will find the audio response has a falling characteristic. The response falls off between 3 and 6 dB per octave above 1 KHz. One can accomplish that in the K3 by setting SSB RX EQ to 1600 = -3, 2400 = -5 and 3200 = -6 and by setting CW RX EQ similarly. I tend to set both 50 and 100 Hz bands to -16, 200 to -6, 400, 800 & 1600 to 0, 2400 to -4 and 3200 to -6 as that significantly reduces both low frequency "rumble" and high frequency "hiss". The other thing to do to make the K3 less noisy (less hiss) is to increase the AGC threshold and decrease the AGC Slope so the AGC system does not "pump up" the background noise. Careful adjustment of AGC parameters and RX EQ will result in a very "comfortable" sounding K3/K3S. 73, ... Joe, W4TV On 6/27/2016 10:19 AM, Ignacy wrote: I also feel that K2 is easier to listen to under average conditions than K3. My K3 has the DSP board updated. The issue could be due to 2 factors: AF distortion and AGC properties. K2 has a very sweet AGC. K3 had a very high AF distortion level that was mitigated by a series of upgrades ( at least choke and DSP board). If you read old messages, there is a message by a Russian who looked at initial IMD level (very high) and documented improvements by adding large capacitors in several places. I listened to 10m CW at WPX contest with K3 and SDRPlay, both with good speakers. The last one sounded slightly cleaner although SDRPlay would have easily overloaded with strong signals. It would be interesting to see whether K3S sounds better than K3, perhaps due to a number of small changes. Ignacy, NO9E -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-K3-audio-and-the-K2-fan-tp7619296p7619312.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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 Message delivered to li...@subich.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 / K3 audio - and the K2 fan
Those changes (or an alternate) were included with the updated K3 DSP board. They are present in all K3s sine the release of the DSP board update. 73, Don W3FPR On 6/27/2016 10:19 AM, Ignacy wrote: If you read old messages, there is a message by a Russian who looked at initial IMD level (very high) and documented improvements by adding large capacitors in several places. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 / K3 audio - and the K2 fan
I also feel that K2 is easier to listen to under average conditions than K3. My K3 has the DSP board updated. The issue could be due to 2 factors: AF distortion and AGC properties. K2 has a very sweet AGC. K3 had a very high AF distortion level that was mitigated by a series of upgrades ( at least choke and DSP board). If you read old messages, there is a message by a Russian who looked at initial IMD level (very high) and documented improvements by adding large capacitors in several places. I listened to 10m CW at WPX contest with K3 and SDRPlay, both with good speakers. The last one sounded slightly cleaner although SDRPlay would have easily overloaded with strong signals. It would be interesting to see whether K3S sounds better than K3, perhaps due to a number of small changes. Ignacy, NO9E -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-K3-audio-and-the-K2-fan-tp7619296p7619312.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 / K3 audio - and the K2 fan
Ted, I have a fully-developed K2 #380) including KPA100, KAT100, KDSP2, etc. I've even added the 3rd party MA Board and the Rework eliminator (together). I also did a full update of everything in 2014 (ROMs, some updates I'd not done when last I worked on the K2 in 2004 or so, etc.; it was quite a job and my Hakko desoldering tool proved its worth!) The K2/100 and KX2 are my in-the-back-bedroom setup: Takes less space on my smaller desk, and I'm able to use any antenna by throwing switches out in the shack. Mostly of late I use the QRP KX2; sort of more fun. My shack off the garage is not heated and not insulated: Too hot on hot days, and too cold on cold days; the shack is better equipped (KX3/PX3 and K3/P3/KPA500/KAT500) but not always pleasant to use. I have listened to both the K3 and K2 alternately side by side in the shack, in fact this morning. They do sound different, but I can't say one is better than the other. Of course, since use DSP filters in the K2 all of the time, and in the K3 most of the time, that's a variable unique to me and my filter settings. The K3 is easier to operate, especially on SSB, due to the P3; I have no panadapter set up for the K2, one of the few third-party options I've missed. One of these days I may replace the K2/100 with a more state-of-the-art radio; I started building mine in July 1999 and the design is a bit long in the tooth, but still solid today! Since I've had no issues with my KPA100's fan, noise or otherwise, I wonder if you should consider replacing yours, Ted? Of course, one ear has stone deaf for 50 years and the other one is not spectacular (Advantage: No need for subRX in K3!), but I do hear computer fans, the fan in my power supply, etc. -- so I'm not "fan deaf" 73, Phil W7OX On 6/26/16 3:56 PM, Dauer, Edward wrote: I know this is runs the risk of reopening an old thread, so I’ll keep the question focused: During the FD this weekend I spent about half the time with the K3 line, and half with the K2. Using the same headset, same antennas, same ambient environment, but of necessity different filter configurations, I now understand why some people prefer the K2’s audio to the K3’s. It is a matter of taste, of course. But I found the K2 simply easier to listen to for long stretches – at least for my ops which are CW only. It’s hard to describe the difference in words, so two questions. 1. Has anyone done an analysis of the frequency response of the audio stages in both rigs, to compare them empirically? My guess is that the K2’s curve is skewed toward the lower ranges.2. I have never set the RX EQ in the K3 – it’s still on what it was when I bought it. Has anyone tried to make a K3 sound more like a K2? If so, what settings do the best? This encomium for the K2 ends, however, when it hits the fan. Running QSOs in the contest with the K2 and KPA100/KAT100 (in an EC-2) kept the amp’s fan on pretty much continuously – and the sound it makes is something like a cat being slowly tortured. It is much more annoying than the fans in the K3, the KPA500, and the K3 power supply blowing simultaneously, which they almost never do. Could be a bad bearing? The amp hasn’t been used for 100 hours yet. If it’s not a flaw, is there an after-market fan that fits the KPA100 cutouts and which moves as much air but doesn’t make as much noise? Thanks . . . Ted, KN1CBR __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 / K3 audio - and the K2 fan
Can't answer your second question about the fans, but I initially thought that my K2 "just sounded 'nicer'" than my K3. It's not a huge difference, and I'm fairly deaf anyway, so I don't have a definitive, iron-clad answer but: 1. I usually use lightweight headphones [single narrow metal band] with the small foam covered phones on my K2 and a Heil Proset I got from Elecraft on my K3. When I finally tried the lightweight ones on the K3, the sound improved. I tried a very old Sony headset [1960's from a reel-to-reel recorder] and it too improved the sound, at least subjectively. The K2 sounded about the same with it. I've concluded that the radio-headphones are a system and the components work together. 2. Jim, K9YC, gave me some advice on the RXEQ, the most important of which was ... "go very slowly while adjusting it." Make a change, and then use it for awhile. That stopped my flailing around with it, and I found I could improve the audio quality noticeably. My current settings, which I haven't messed with in several years sort of roughly mirror the response of a couple of "programs" in my hearing aids. The differential gain achievable in the K3 RXEQ is much less than my hearing aids, but somehow, it smooths out the sound. [That's a technical term used by someone who doesn't really know what's happening. :-)] My observations are mainly for narrow BW CW, I've listened some on sideband, but not enough to figure anything out. My K2 does not have DSP, and I've wondered if the less-square response of the crystal filter isn't part of the equation too. The K3 DSP seems like a brick wall at times. Maybe someone with a DSP K2 and a K3 has some observations. 73, Fred K6DGW - Northern California Contest Club - CU in the Cal QSO Party 1-2 Oct 2016 - www.cqp.org On 6/26/2016 3:56 PM, Dauer, Edward wrote: My guess is that the K2’s curve is skewed toward the lower ranges.2. I have never set the RX EQ in the K3 – it’s still on what it was when I bought it. Has anyone tried to make a K3 sound more like a K2? If so, what settings do the best? __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 / K3 audio - and the K2 fan
Ted, You would find the K3 RX EQ to be beneficial to your ears. The IF filtering in the K2 causes the high frequency to roll off, but the stock K3 has a flatter response. If you have an older K3, the DSP board exchange or the LPF added to the DSP board will help by rolling off the high frequency content. Check the serial numbers on the K3 mods page to see if your K3 has the updated DSP board with the high frequency filter. The fan on the K2/100 is what it is, I don't know of any substitutes, but make sure the CAL TPA setting is correct to start with. You can run the fan on the HI-LO setting so the fan is on constantly at low speed and will only go to high during extended transmit periods. You can also put a slow running muffin fan above the K2/100 heatsink such as is described in the pages of Tom Hammond's (SK) website http://www.mmccs.com/mmarc/n0ss/kpa100_aux_cooling_fan_duct.pdf. His website is preserved by the Mid-Misouri Amateur Radio Club. 73, Don W3FPR On 6/26/2016 6:56 PM, Dauer, Edward wrote: I know this is runs the risk of reopening an old thread, so I’ll keep the question focused: During the FD this weekend I spent about half the time with the K3 line, and half with the K2. Using the same headset, same antennas, same ambient environment, but of necessity different filter configurations, I now understand why some people prefer the K2’s audio to the K3’s. It is a matter of taste, of course. But I found the K2 simply easier to listen to for long stretches – at least for my ops which are CW only. It’s hard to describe the difference in words, so two questions. 1. Has anyone done an analysis of the frequency response of the audio stages in both rigs, to compare them empirically? My guess is that the K2’s curve is skewed toward the lower ranges.2. I have never set the RX EQ in the K3 – it’s still on what it was when I bought it. Has anyone tried to make a K3 sound more like a K2? If so, what settings do the best? This encomium for the K2 ends, however, when it hits the fan. Running QSOs in the contest with the K2 and KPA100/KAT100 (in an EC-2) kept the amp’s fan on pretty much continuously – and the sound it makes is something like a cat being slowly tortured. It is much more annoying than the fans in the K3, the KPA500, and the K3 power supply blowing simultaneously, which they almost never do. Could be a bad bearing? The amp hasn’t been used for 100 hours yet. If it’s not a flaw, is there an after-market fan that fits the KPA100 cutouts and which moves as much air but doesn’t make as much noise? Thanks . . . Ted, KN1CBR __ 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 Message delivered to donw...@embarqmail.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 / K3 audio - and the K2 fan
K2s audio IS sweet sounding, isnt it? :-)(Not meant as a dig at the K3; in my - ok, admitted somewhat limited - experience, Im not sure Ive ever heard an SDR receiver having audio that matched that of a good analogue receiver, K2, Drake R4B, etc., notwithstanding any of the tweaks allowed by the SDR and/or any associated computer sound card.) - Paul, N6LQ __ 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 Message delivered to arch...@mail-archive.com
