[Kenwood] TS-940 Audio Problem

[Fern]

Hi Dennis and the group. Check and see if the transmit audio is bad on both sidebands (lsb and usb). It's most likely only bad on one of them so it's just a matter of correcting the frequency shift of one of the sideband oscillators. You'll have to sweep the response on both sidebands which should be identical. If you want a good sounding radio on ssb, it's very important to get this just right. 
     73 from Fern


----- Original Message ----- 
From: "Dennis Klipa" <klipadk at gmail.com>
To: <kenwood at mailman.qth.net>
Sent: Monday, November 02, 2009 5:34 PM
Subject: [Kenwood] TS-940 Audio Problem


> 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
>