Sansamp RBI hum

[Kroot]

I bought a used RBI and wondering if this is a problem with my unit or how I am setting it up.

I have a Ampeg B2 combo I hooked it up to a few different ways

bass > rbi (front/rear) panel input > ampeg (front panel/power amp) input = fairly loud hum even with all volume knobs at 0

bass > ampeg front panel input > rbi in effects loop = no hum but what seems to be premature distortion at relatively low gain (peak light does not blink)

I used to own the sansamp bass driver pedal hooked directly into a power amp and it was very quite and did not distort till at least past 12 o'clock so Im thinking I got suckered into buying a lemon

[Zooberwerx]

Any time I hear the term "hum", I immediately think ground or ground loop problems. I assume you're using a shielded instrument cable? Are you tapping into the "power amp in" jack?

Riis

[Kroot]

while using the power amp in jack and the instrument in jack there is a loud hum that stays a relatively constant level even as i turn up gain/volume regardless if the rbi is active or not. when i hook it through the effects loop i get the normal noise of the pickups but get what i think is weird distortion more noticeably on the highs

for reference amp was set with 3 bands at 12 o'clock and gain around 10 o'clock
all cables are shielded

I can try and pick up a 2 prong adapter to temporarily lift the ground to see if its a ground loop tonight

[Zooberwerx]

Originally Posted by Kroot

while using the power amp in jack and the instrument in jack there is a loud hum that stays a relatively constant level even as i turn up gain/volume regardless if the rbi is active or not. when i hook it through the effects loop i get the normal noise of the pickups but get what i think is weird distortion more noticeably on the highs

for reference amp was set with 3 bands at 12 o'clock and gain around 10 o'clock
all cables are shielded

I can try and pick up a 2 prong adapter to temporarily lift the ground to see if its a ground loop tonight

So, the Ampeg hums irrespectively of whether you're using the "instrument in" or "power amp in" jacks? Which RBI output are you using?

I looked at both manuals and neither shows a ground lift option. Figures!

Riis

[Kroot]

yes both inputs hum at 0 volume

whats seems odd is that it doesn't get amplified with gain/volume

after playing with different basses and the -20db switch on rbi input 2 i realized what I was hearing before was just a hotter signal than I had previously causing the drive knob to distort sooner than I expected.

[Zooberwerx]

On my way to work but, in the meantime, let's rule out the simple stuff. Any way you can plug the RBI into any other free-standing power amp / speaker configuration (e.g PA)?

Riis