+++++++++++++++++++ From: "Don Brown" To: "Dave" , Subject: Re: [Elecraft] KDSP2 Build Date: Sat, 24 May 2003 16:55:51 -0500 Hi The mod is on John Grebenkemper web site http://home.pacbell.net/johngreb/modifications_to_the_ksb2.pdf It involves changing out several caps on the KSB2 board. You must have the new matched crystals also. I have done this mod on a couple of K2's and it is really nice. Should work well with the DSP module. -- snip -- Don Brown KD5NDB ----- Original Message ----- From: "Dave" To: Sent: Saturday, May 24, 2003 3:54 PM Subject: Re: [Elecraft] KDSP2 Build > Don > > Is your "2.5 KHz SSB bandwidth mod" the 2nd filter mod, or is there another > one? My K2's SSB filter is a bit too narrow at 2.2 KHz for my liking, even > with the second filter mod. > > Dave, G4AON > > ----- Original Message ----- > From: "Don Brown" > To: "Elecraft" > Sent: Saturday, May 24, 2003 9:46 PM > Subject: [Elecraft] KDSP2 Build > > -- snip -- Now I need to > > go back and do all the A to B mods on #1808 and install the 2.5KHz SSB > > bandwidth mod. At first try out the KDSP2 is very nice. I only did a quick > > check out with the default settings. Sounds good. > > > > Don Brown > > KD5NDB ++++++++++++++++ From: "Don Brown" To: "Tom, W6WW" , Subject: Re: [Elecraft] KDSP2 Build Date: Sun, 25 May 2003 11:58:34 -0500 Hi The parts to do John's mod do not come with the KSB2. You will need to change 10 to 12 caps to different values. I ordered the caps from Mouser but Elecraft may have them. It would be easier to install the caps when building the KSB2 as some of them are hard to get to on a completed board. If you are doing a retrofit then I would highly recommend a Hakko solder removal unit. John lists the values for a 2.5 KHz, 2.2 KHz and 1.9 KHz all with better ripple specs. I have done the 2.5 KHz 3 or 4 times and the 1.9 KHz once. The K2/100 I built for Eric had the 2.5 KHz filter in it. The 1.9 KHz filter only requires 4 caps to be changed and has better ripple than the stock 2.0 KHz filter. The values needed for the 2.5 KHz filter are two each 39pf 27pf 150pf and four 33pf all 5% monolithic ceramic .1 inch lead spacing. You will also remove two 10 pf caps. Remember this may not work with the older crystal sets so you may need to install a new set of matched crystals. If you are replacing the crystals the cap swap is easier to do while the crystals are removed. Anyway SN 1808 and SN 2174 have the 2.5 KHz filter mod and KDSP2's. SN 3171 will be built with the 2.5 KHz when I get time to finish it. I am happy with how they sound. -- snip -- Don Brown KD5NDB ----- Original Message ----- From: "Tom, W6WW" To: "Don Brown" ; Sent: Sunday, May 25, 2003 8:13 AM Subject: Re: [Elecraft] KDSP2 Build > I just received my KSB2. Would it have any of these mods already included? > Would it be wise to incorporate these mods as I build the KSB2 or finish the > unit and then make the mods? > > 73, > Tom, W6WW > K2 #3453 +++++++++++++++++ Date: Sat, 31 May 2003 07:21:56 -0400 From: Dale Boresz To: elecraft at mailman.qth.net Subject: Re: [Elecraft] KI6WX Crystal Filter Bandwidth Mod ? George Winship wrote: >I am going to do this mod when I get the new crystals and caps. Would >like some feedback from those who have done it. Which one did you >choose, the 2.2 or the 2.5 KHZ? Were you happy with the results? If by >chance you have done both, which did you like better and why? > > > George, I just completed the 2.5KHz mod, and am very pleased with the results. The receive audio is more natural with the wider bandwidth, and from what I can hear while monitoring my signal on the 746PRO while transmitting into a dummy load, the transmit quality is better as well. -- snip -- In summation, I don't think you'll regret doing the 2.5KHz mod George. 73, Dale / WA8SRA +++++++++++++++++ Date: Sat, 31 May 2003 15:43:18 -0700 (PDT) From: Don Rasmussen Subject: RE: [Elecraft] KI6WX Crystal Filter Bandwidth Mod ? To: elecraft at mailman.qth.net George Winship wrote: >Which one did you choose, the 2.2 or the 2.5 KHZ? Were you happy with the results? ============================================ George, I chose the 2.5khz SSB bandwidth for K2 #3312 and would suggest that to anyone who uses the SSB mode at all. I was completely unhappy with the pinched audio during SSB operation of my first K2 (#630) at any BFO setting. The rig became a "CW only" option here. With the new crystals in K2 #3312 and the wider KI6WX bandwidth mod, I find that the BFO frequency can be fine tuned just as if there were a TONE control for receive audio on the rig. I use OP1 for midrange, OP2 for enhanced BASS, and OP3 for enhanced TREBLE. The selectivity is still very good at 2.5khz (measured using Spectrogram) and the improvement in clarity is simply amazing. I find that I'm using the K2 for everything I do now, and recently reprogrammed my memories to reflect this. I use the left column for CW (fast AGC) and the middle column for SSB (SLO agc). 1=7.03c 4=14.03c 7=21.03c, 2=7.23L 5=14.23u 8=21.3u. The right column is for WARC bands 3=10.1c 6=18.07c 9=24.89c and the "0" memory is for my 10m ground wave net. The additonal fidelity on SSB, and the improvement in frequency stability (credited to another KI6WX mod) for CW have transformed what was a very strong CW novelty rig (K2 #630) into one of the best general purpose HF's I've ever owned. 73, de WB8YQJ/6 Don Carlsbad, Ca. gwwa5uih at hotmail.com Fri May 30 22:05:05 2003 ++++++++++++++++ From: "George Winship" To: Date: Sat, 31 May 2003 20:29:11 +0100 Subject: [Elecraft] Re: KI6WX Crystal Filter Bandwidth Mod? Thanks to all who responded to my question about this mod. The 2.5 KHZ was overwhemingly favored over the 2.2 KHZ . 73, George, NC5G K2-2217 ++++++++++++++++