I replaced C25 and C26 with .22 uF ceramic capacitors the other evening as Matti has suggested. It does make a nice difference in the low end.
I have the KAF2 filter and am using the standard SSB filter as constructed in Rev E of the KSB2 module. The specs state it is a 2.3 kHz filter. I notice that the coupling capacitors in the KAF2, C12 and C13 are .22 uF devices. I can't help but wonder what changing all four caps C25 and C26 on the control board and C12 and C13 on the KAF2 to .33 uF would do. I don't have enough .33 uF ceramic caps in the junk box or I would try it. Perhaps I will remember to order some from Mouser next time I place an order. I have some polypropylene caps of the right value, but they are a bit to large physically to fit. The audio buffs seem to favor these over the ceramic types as they say they have a better sound to them. Be interesting to see if it would be noticeable. 73, Darrell VA7TO K2#5093 On Wednesday 31 October 2007 09:48, Marteinn Sverrisson wrote: > Hi > > While trying to improve the K2 RX audio response specially for SSB, > I noticed lack of low frequencies, looking at the schematics I find > the the LP cutoff is abt 640 Hz, determined by C25, C26 and the 5k vol > pot ( this is wheather using DSP or not). > By increasing C25 and C26 to 0.2uF (from 0.1uF) the LP cutoff is > moved to abt 320 Hz. This makes better sounding SSB signals and also helps > in CW mode when copying low pitch signals. > > To lower the LP cutoff, I soldered 0.1uF SMD caps across > C25 and C26 on the control board. To my ears K2 now sounds better..... > > 73, Matti > > ps. I use 2.4 kHz X-Tal filter -- Darrell Bellerive Amateur Radio Stations VA7TO and VE7CLA Grand Forks, British Columbia, Canada _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
