[Kenwood] TS-940 Audio Problem

Mon Nov 2 19:34:28 EST 2009

When my friend, John, transmits on LSB on his TS-940 with his MC-60
microphone, it sounds like all of the bass has been stripped from his voice,
as if there were a narrow band filter in the mic circuit. This is true on
all bands. We have taken his microphone and put in on my TS-940 and it
sounds great, according to on air reports. It is a little more sensitive
that my MC-60 but we only have to turn down the mic gain one notch to keep
the ALC within range with his mic on my 940. It doesn't matter which
impedance you select on the mic or whether the preamp in the mic base is on
or off, the audio still sounds bad. The speech processor is turn
off. Turning it on only makes matters worse. So it is not the microphone.
When we turn down the Power down on his rig to about 5 watts out, the
audio quality increases but only slightly.
We have tried LSB, USB, AM and FM modes. The problem is only present on
LSB.
The obvious adjustments to check are:
1. SSB Mode Frequency Response
2. Supply Voltages
3. Carrier Suppression (balanced)
But before I open the cover, I wanted to find out if anyone had experienced
this problem before or has any suggestions on what to look for.
Thanks, es 73,
Dennis, N8ERF