Audio Output Balance Question

[ron]

I seem to have a stronger (louder) signal on one side of my raspberry pi than the other.  Meaning one side of audio on a stereo receiver appears to be louder than the other.  The stereo is zeroed out balance wise, all cables are connected the pi fully and I don't think I have a balance option on my transmitter.  I have the EDM RDS unit for a transmitter.  The output from my pi with the amixer and aplay commands are:

pi@FPP ~ $ amixer
Simple mixer control 'PCM',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback -10239 - 400
  Mono: Playback 347 [100%] [3.47dB] [on]
pi@FPP ~ $ aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=ALSA
    bcm2835 ALSA, bcm2835 ALSA
    Default Audio Device
sysdefault:CARD=ALSA
    bcm2835 ALSA, bcm2835 ALSA
    Default Audio Device

Am I missing an option for stereo out of the pi or setting the left and right balance?

Thanks.

Ron