Aha! Thanks for catching that Bill. I'll clarify the procedure. Replacing the SMDs is fine. The value difference is not significant. The intent was to make the mod as easy as possible for everyone. But the instructions should be crystal clear, Hi!
Ron AC7AC -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bill W4ZV Sent: Tuesday, December 09, 2008 3:01 PM To: [email protected] Subject: Re: [Elecraft] K3 Audio Upgrade Mod Bill W4ZV wrote: > > ri > > Alexander Ponomarenko-5 wrote: >> >> GA, >> >> today I has same time for install K3-AF-mod (second part with R19 and >> R20). It was easy job. Yes, it's really worked! Now line-out are worked >> better! Here is plots "before" and "after" mod. >> >> Line-OUT before replaced R19&R20 >> > > Priwet Alex! > > I believe you have made a mistake. The 51 ohm resistor should be placed > ***ON TOP*** of the existing SMD resistors (i.e. in parallel with the > existing resistors and NOT replacing them). Please read the instructions > more carefully. > > 73, Bill W4ZV > Alex I believe I see what caused your misunderstanding. On the Main Mod Kits page, it states: "Line Out Change: KIO3 Main Board: R19/20 (input to line-out transformers) changed from 600 to 51 Ohms to increase line-out low distortion output levels." http://www.elecraft.com/K3/k3_app_notes.htm But on page 8 of the actual mod instructions it says: "Line Audio Output Modification This modification reduces the value of two resistors in the left and right channel line audio outputs on the KIO3 board by adding 51-ohm resistors in parallel with them. The existing resistors are surface mount types. Since the new resistors are wired in parallel with them, it is not necessary to remove the existing SMD units." http://www.elecraft.com/K3/mods/K3%20AF%20Stage%20Upgrade%20Instructions%20R ev%20A.pdf As has been noted by others before, I'm not sure why Elecraft did not suggest replacing the existing 600 ohm resistors with 47 ohms (parallel combination of 600 and 51). Perhaps they were concerned with the problem of potentially lifting the board traces when removing the 600 ohm resistors. The documentation on the main mods page (1st link above) needs to be corrected. 73, Bill W4ZV 73, Bill W4ZV -- View this message in context: http://n2.nabble.com/K3-Audio-Upgrade-Mod-tp1611843p1636358.html Sent from the Elecraft mailing list archive at Nabble.com. _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
