Amp not putting out much sound

[Jpm4536 0]

I have a us acoustics usx2080 that i got from Audio Clinic off of ebay and it is hooked up to my pioneer premiere 720prs speakers and it just doesn't seem much louder than the radio straight to the speaker. My gain is at about 3/4 which seems kinda high to me but thats where the DMM put it. My HU is an Alpine 9885 and i used a 1000hz wave to set my gain to 17.9 volts. Someone told me it may be an install problem but what kind of install problem could cause this? Wouldn't it be either working or not working? Also, how much louder should this amp be than the HU? Thanks for any help or tips!!!

[solobarric 0]

try checkin out your rca'a might not be gittin a good signal, also on the amp is there any kind of filter that is turned on?