+++++++++++++++++++ Reply-To: "Ron D'Eau Claire" From: "Ron D'Eau Claire" To: "Elecraft List" Date: Thu, 20 Jun 2002 14:26:56 -0700 Subject: [Elecraft] Muddy SSB I hate it when I discover something wrong with something I don't use often. The compulsion to "fix it" is as strong as if I needed it every minute. So it is with the audio quality on SSB on my K2. As others have mentioned, the Upper Sideband, in transmit, sounds "muddy", "constricted"... lots of terms have been used. They all add up to "awful audio" compared to the Lower Sideband. Until I started working on this problem, it had been nearly a decade since my last SSB QSO. That is until one night I got on to chat with Lou, W7DZN specifically to try out the K2 in SSB. I thought I had the BFO settings tweaked. Not so. We spent an hour doing "on the fly" changes to my BFO settings for the best audio quality. The USB never did get quite "right". We ASSUMED (watch out for that word, it bites) that the problem was the point of the low frequency cut off setting on the filter. That is, fixing the problem was a matter of getting the BFO on the right frequency relative to the filter bandpass. My BFO settings were very close to the Elecraft recommendations and the spectrogram images looked just like the examples posted in several places. Today I made a few recordings of my own voice. I recorded my own voice on a good tape recorder with the K2 in SSBA-BAL mode with the recorder plugged into the K2 headphone jack. So the "tuning" of the received audio should be perfect. As Lou reported, LSB is fine. USB sounds like I'm in the bottom of a barrel with a pillow over my face. Moving the BFO frequency does not make a substantial difference. Indeed, the problem does NOT appear to be with the low frequency cutoff, but with a loss of most of the high frequencies on USB! This is NOT apparent on receive even when using the OPT1 filter for receive. Both sidebands of signals sound very good on receive (I have installed the filter flattening mod). Spectrogram does not show any significant difference in the shape of the bandpass between the two filters out past 2.5 kHz. Yet, most of the higher audio frequencies (above probably 800 Hz) are highly attenuated on only the USB. In short, there is NO evidence of anything in the OPT1 filter that is causing this, and I can't imagine what else in the K2 could cause loss of high frequency response on one sideband but not the other! Any ideas out there?? I'm apparently not the only one experiencing this. I've heard similar-sounding K2's on the air and there have been other posts on here about a problem that sounds just like this. Ron AC7AC K2 # 1289 +++++++++++++++ Reply-To: "Ron D'Eau Claire" From: "Ron D'Eau Claire" To: "Elecraft List" Subject: Re: [Elecraft] Muddy SSB Date: Thu, 20 Jun 2002 15:00:07 -0700 Tim wrote: > There are some specific mods, both "Elecraft approved" and others, that > address some of these issues. KI6WX has a series of mods he has developed > that address many of these issues. ... In addition, there are some pages off of the elecraft home > page that cover some of this. > > I have a few questions that will help us to further identify the problems, > and how to fix them. What Mic are you using, and how is is wired in the > radio? Which mods for ssb have you put in the radio, or is it stock from > the time you constructed it? > > I will look through what I have here that I saved, and if someone doesn't > have a better answer in the next few hours, I will send some additional > information to this message. That's news to me. I thought that I had looked at all of KI6WX's mods and have chatted with him about some of them. As far as I know ALL of his mods have to do with receive audio only. My K2 transmit circuits is "stock" EXCEPT for the 2nd XFIL flattening mod recommended by Wayne - which affects ONLY receive audio. I made the variation on that mod that KI6WX suggested that improves the flatness a bit more. To answer your other question, I am using a Radio Shack 21-1172D microphone. Audio recordings using it sound good and, as I mentioned, it sounds fine on the lower sideband. I want to make it clear that the audio on USB is quite intelligible, but not up to the standards of most rigs I hear on the air. The LSB audio is more like what I'd expect a good SSB rig to sound like. At first I "assumed" (that word again) that the difference was being caused by the shape of the ladder filter bandpass that was emphasizing or de-emphasizing the higher frequencies when the BFO was switched from one end of the bandpass to the other. But that is NOT apparent looking at the response with Spectrogram. Ron AC7AC K2 # 1289 ++++++++++++++ From: "Steve & Anne Ray" To: "Elecraft" Date: Thu, 20 Jun 2002 22:08:20 -0400 Subject: [Elecraft] Muddy SSB I am no expert, but had complaints about my audio on USB 20 and 17 sounding to Bassy, playing with the FL1 filter setting did not seem to help. If I switched to LSB on 20 and 17 got good audio reports. The opposite was true on 15-10 meters. This is to be expected as the rig inverts above 17 meters. Anyway I was running a Kenwood MC50, did the mod to improve the intermod for PSK when I built the SSB module, and then changed R14 to 10K. After a lot of had scratching and talking to Bob Heil at the Dayton Hamfest, I ended up buying a HC-5 Heil Element and installed it in my MC50 Mic. I then set the BFO for FL1 per the manual and I have been getting excellent reports. I also recorded (into my computer) my audio (SSBA Balanced Mode) with the original Kenwood MC50 and then with it using the HC-5 element. I am no sound expert, but it sure sounded better to me with the HC-5 element. I have left the 10K at R-14. Anyway I am now getting unsolicited reports of good sounding audio, whereas before the unsolicited complaints were my audio was two bassy and muddy. Better yet, on a purely subjective basis I seem to have better luck working DX. Realize nothing exotic, but I do manage to get through.even in pileups (realize the pile ups are for UA, HA, G, South Americans, etc), nothing exotic, but I am happy. The usual I have no connection with Heil, just happy with the results. Good Luck 72, Steve Ray K4JPN ex K1VKW EM82ep Warner Robins GA Elecraft K2 1422 Heath Fan HW-101, HW-8 +++++++++++++++++++ Reply-To: "Ron D'Eau Claire" From: "Ron D'Eau Claire" To: "Elecraft" Subject: Re: [Elecraft] Muddy SSB Date: Thu, 20 Jun 2002 19:36:31 -0700 Thanks for the comments, Steve. What I don't understand is how the mic can have such a big effect on only ONE sideband! But your experience tells me it is something to explore. Thanks. If one wants to do "serious" SSB, a good audio equalizer seems to be an excellent investment to "tweak" the audio to match the mic, operator's voice and filter characteristics.I last did any real "phone" work was back in the "AM" days with my Viking Ranger. One topic on the bands was always about changing capacitor values in the speech amplifier to do just that! Ron AC7AC K2 # 1289 ++++++++++++++++++ From: "Glenn Maclean" To: "Ron D'Eau Claire" , "Elecraft List" , "Timothy A. Raymer" Subject: Re: [Elecraft] Muddy SSB Date: Thu, 20 Jun 2002 22:40:59 -0700 Ron, Thanks for your post. I too am having transmit audio problems. I posted a message about it last week as you know. I am using the Elecraft MH2 Heil microphone. I have done the SSB flattening mod. I used spectrogram and put my K2 on 20 meters to adjust upper and lower side band filters on the OPT1 filter. My spectrogram adjustments look just like the samples that have been posted on the Elecraft web site. The audio sounds terrible very constricted and metallic or what ever you want to call it. I did the same thing you did with an on the air QSO with John K7FD. I was able to improve the audio some but it is not to my liking by any means yet. It is still constricted and metallic sounding. My next move is to try a different microphone. I have had my MH2 mic since Pacificon last fall. I have not tried SSB with the MH2 mic until this week. I am like you mostly a CW operator. I would like to use SSB occasionally now that the Elecraft100 watt amp is out and the little HF Packer amp http://www.hfprojects.com I plan to get the Elecraft 100 watt amp in the near future. I have one of the original SSB boards with the newer firmware prior to the amp firmware.. Eric, Wayne or Gary perhaps we can get some input from you guys on SSB transmit audio improvements. I know that Ron and I are not the only ones with crappy transmit audio. I know some K2's are sounding great. Thanks in advance for any input from anyone. Glenn WA7SPY +++++++++++++++++ Date: Thu, 20 Jun 2002 19:52:03 -1000 From: John Buck To: Glenn Maclean Cc: Ron D'Eau Claire , Elecraft List , "Timothy A. Raymer" Subject: Re: [Elecraft] Muddy SSB Turn off the audio speech compressor, reduce power to 5 watts and listen to it. Does it improve? This sounds like too much audio gain and compression. Aloha, John KH7T +++++++++++++++++ Date: Thu, 20 Jun 2002 22:56:58 -0700 From: Wayne Burdick Organization: Elecraft To: Glenn Maclean Cc: Ron D'Eau Claire , Elecraft List , "Timothy A. Raymer" Subject: [Elecraft] Re: Muddy SSB Glenn (and others), Your K2's should have excellent transmit audio with the MH2 and any other compatible mic, so I'm not sure what the problem may be. Gary and I will look into this immediately. I'm sure we'll get it resolved. 73, Wayne Glenn Maclean wrote: > > Ron, > Thanks for your post. I too am having transmit audio problems. I posted a > message about it last week as you know. I am using the Elecraft MH2 Heil > microphone. I have done the SSB flattening mod. I used spectrogram.... ++++++++++++++++++++ From: "Glenn Maclean" To: "Wayne Burdick" Cc: "Ron D'Eau Claire" , "Elecraft List" , "Timothy A. Raymer" Subject: Re: [Elecraft] Re: Muddy SSB Date: Thu, 20 Jun 2002 23:10:57 -0700 One other thing I have done is I set up the SSBC and SSBA settings per the MH2 mic instructions Glenn WA7SPY +++++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'Elecraft List'" Subject: RE: [Elecraft] Muddy SSB Date: Fri, 21 Jun 2002 08:05:21 -0700 Glenn WA7SPY wrote: Thanks for your post. I too am having transmit audio problems. I posted a message about it last week as you know. I am using the Elecraft MH2 Heil microphone.... A-yep. It was my thinking about your message the other day and my *assumption* (when will I learn NOT to use that concept??) that it was a simple matter of setting the BFO's correctly that got me to looking at mine again today. My mic is a dynamic, which usually has pretty good bass response -something not necessarily good in a communications mic. But it's very significant that you are using the ELECRAFT/HEIL MIC! So your audio should sound about "as good as it is going to get!". Ron AC7AC K2 # 1289 ++++++++++++++++++++ To: elecraft at mailman.qth.net Date: Sun, 23 Jun 2002 19:46:59 -0700 From: k6se at juno.com Subject: [Elecraft] K2 Mushy Audio I spent about an hour operating Field Day with my K2 (at home, class 1D) yesterday. After receiving several comments of "good signal", I recalled that a couple of K2 owners said they had bad, mushy audio on one sideband or the other, so I asked a few of the contacts I made how my audio sounded. They all said, "Excellent". This included QSOs on 15m and 20m (equivalent of USB and LSB on either band), so I guess my K2 (#2622) doesn't have that problem. I use a cheap 500-ohm dynamic mike element purchased frrom Mouser for $3.59 (Mouser stock #25LM032).. 73, de Earl, K6SE +++++++++++++++++++++ From: "Glenn Maclean" To: "Elecraft List" Date: Thu, 4 Jul 2002 07:57:40 -0700 Subject: [Elecraft] No More Muddy SSB!!!!! I received and installed the replacement crystals on the RF and SSB adapter boards. All I can say is it has made a huge improvement in both receive and transmit on SSB and CW. I aligned all the filter settings using spectrogram for CW and SSB. I am now getting excellent transmit audio reports on SSB. The receive signals are much more crisp in both CW and SSB compared to the old crystals. When I cycle through the filters the signal is much more even with the new crystals. My K2 is serial number 323. The original crystals were not as closely matched back then. Thank you Wayne and Eric for resolving my SSB transmit audio issue with the matched crystals. Glenn WA7SPY +++++++++++++++++++++ From: "Glenn Maclean" To: "Robert Fanfant" , "Phil Wheeler" , Cc: "'Elecraft'" Subject: Re: [Elecraft] Poor Audio Report With K2 Date: Sat, 20 Jul 2002 20:50:17 -0700 My K2 serial number is 323. As Ron AC7AC stated the new crystals cured my muddy SSB problem. I also have found in receive the crystals are much more even in signal strength when I cycle through the 4 filter settings. With my old filters no matter how I set the filters using spectrogram I could not get the signal strength to stay the same. In my tightest filter setting I was getting a lot of attenuation in receive. Not so with the new matched crystals. I replaced all 14 crystals. 7 on the RF board and 7 on the SSB adapter board. I am not sure when Elecraft went to the matched crystals for the K2. Glenn WA7SPY +++++++++++++++++++ Date: Sat, 20 Jul 2002 22:42:23 -0700 From: Wayne Burdick Organization: Elecraft To: Glenn Maclean Cc: Robert Fanfant , Phil Wheeler , rondec at easystreet.com, Elecraft Subject: [Elecraft] K2 crystal matching and SSB Glenn Maclean wrote: > I am not sure when Elecraft went to the matched crystals for the K2. Glenn (and others), We have always matched the crystals in the K2 very closely (to within 10 Hz or better). We use a very sensitive, precisely loaded test fixture to match based on the crystal's series-resonant frequency. So matching has nothing to do with Phil's or anyone else's SSB signal characteristics. However, a small percentage of crystals supplied by the manufacturer did have higher than average motional inductance (Lm), and thus produced somewhat narrower filter passbands. There's no way to identify these crystals from the rig's serial number since crystals are first matched, then placed into our inventory to be used at a later time. But the small number of higher-Lm crystal sets were probably used up a long time ago. We now use only crystals that have been pre-screened for a specific range of motional inductance by the manufacturer. Nearly all crystal sets that we had shipped already fell into this range, but the screening step guarantees that all K2 builders will get consistent results. Anyone who suspects they might have an SSB TX passband that is too narrow should e-mail gary at elecraft.com. Gary will tell you how to check your filter crystals using a simple test. Elecraft will replace any crystal sets found to be too narrow. Note: The KSB2's nominal bandwidth is 2.2 kHz, with the acceptable range being anything from about 2.0-2.4 kHz. Our goal was to give the K2 "punchy" audio, not "hi-Fi" audio, and this strategy has been proven effective in on-air tests. Still, some operators have experimented with wider filters. In particular, see John Grebenkemper's recently-posted application note. John lists alternate capacitor values for the KSB2 for various bandwidths. 73, Wayne N6KR ++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: , Cc: Subject: RE: [Elecraft] Re: K2 SSB problems Date: Mon, 5 Aug 2002 16:54:52 -0700 What I was referring to specifically, was discussed around six to eight weeks ago and generally subscribed under the subject "Muddy SSB." That, I believe, referred to RX and XMIT, although mostly the latter. From the responses, I gather that poor XTAL's were primarily to blame, and then mostly on a sporadic basis or in early release K2's. Gary "Lyam" Freeman ====================================== I was one of the ones who was a part of the discussion (and getting a fix) for the "muddy SSB" problem. It does NOT show up in receive, as far as I have seen. It is only really apparent in transmit. There is quite a separate issue with SSB receive quality that involves the filter at the output of the i-f amplifier: the 2nd Xfil. This is a simple crystal filter used to "clean up" the signal at the i-f amplifier output in receive. It is NOT used in transmit. This filter has a distinct slope to its bandpass that is apparent in the comparatively wide bandpass used for SSB. It causes the SSB reception on some bands to sound bassy, and on other bands it sounds "tinny" or high-pitched. The change from bassy to tinny is caused by the mixing scheme used in the K2 on the various bands. There is a "fix" for that problem on the Elecraft web site under "Builders Resources". Look for the "2nd xfil Filter Flattening Mod". Note the mod has NO EFFECT on the transmitted SSB signal, only the received signal. You are right that the problem with "muddy" transmit audio quality was apparently limited to a few early K2's, according to correspondence I've had with Wayne and Eric. My K2 is over 2 years old. I used my SSB module for digital (PSK 31, etc.) communications and didn't really check it out on all bands for voice transmission until recently. When I did, I discovered that it was impossible to set the BFO for good audio quality on one sideband. As turned out I had a defective crystal(s) in the SSB module. Changing all the crystals fixed the problem. If you have poor transmit audio quality, I would suggest dropping a line to support at electraft.com. I guarantee you they will jump right on it. There's only one thing that I've seen that works better than an Elecraft rig. That's Elecraft customer support. Ron AC7AC K2 # 1289 ++++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'Helmut Usbeck'" , Subject: RE: [Elecraft] ssb problem Date: Sun, 1 Dec 2002 16:54:20 -0800 That has been a problem with a number of K2's for two reasons. First, is the proper setting of the BFO in relation to the filter bandpass. Setting the BFO by Spectrogram is NOT a good way to be sure that you have a good signal. On mine, with a fairly bassy voice, I have the bandpass set considerable further "up" from the carrier than the sample plots (or the SSB module instructions) suggest. As they say in the SSB module book, it is a good idea to make the final adjustments by listening to yourself on the air. I recorded myself on an auxiliary receiver and made the final adjustment accordingly. Secondly, a number of K2's have SSB (OPT1) filters that are simply too narrow. Elecraft designed for a very narrow SSB filter - something close to 2 kHz. That produces more audio "punch" for a QRP rig, but it's on the edge of becoming too sharp. IF it's too narrow, your audio will either sound muffled or very tinny and "thin". Elecraft sells a replacement set of crystals that are more carefully matched, if that's you problem. I had a narrow filter that wouldn't sound decent and a new set of crystals fixed the problem. Also, John, KI6WX, has some mods posted on his web site (and on the Elecraft site I think) that discuss ways to open up the filter bandpass a little more if you want more fidelity. That's of special interest to the K2/100 operators on SSB out there. If you replace the crystals, you will have to replace all 14 OPT 1 and CW filter crystals so they will match up when switching modes. Ron AC7AC K2 # 1289 -------------- Ever since I purchased and installed the KSB2, and using the MH2 mike I've gotten audio quality reports being muffled, bassy, sounds like you've got a hankerchief over the mike, lacking highs...etc. Checking into it today the problem is still with me.(been on seedub for awhile) I've had several QSO's today using different mikes so I don't think that's the problem. I've gotten these reports on both USB and LSB. Any ideas? Thanks. Regards, Helm. WB2ADT ++++++++++++++++