Have been playing around with the "thump killer mod" from the Feb 97, page
74 QST. It adds two 1N914 diodes across pins 1 and 2 of the NE5532 amp in
the KK7B transceiver. Tried this in my 38S which has a loud click/thump on
key up. The mod reduced the click thump by about 50% (to my ear).
Interestingly, it works better with the 47 ohm resister in at R24 than with
R24 jumpered. The rig sounds better too. Try this and let me know if it
works in your rig. The thump here is now down to level I can tolerate but
am still looking for a way to fully eliminate it.
Another observation. I don't recall who asked but if you take out C33 and
R18, the TiCK keyer sidetone and telemetry tones are MUCH louder. With
these parts removed the tones were loud even without the TiCK mandatory mod.
I had to increase R17 to
10 meg to get the sidetone down to a tolerable level. Any feelings on which
is the best way to beef up the tone volume? 73
Steve Miller KG7PV Portland, OR
(CN-85) Norcal #308 QRP-L #109 ARCI # 9230
[
QRP-L Archive |
]
[
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
1999 |
2000
]