How many farads?

There's about 1200 members who won't get on your case and only an occasional handful that would, but they're not productive members anyway....

The thread is not a question of what amp to buy, but will a cap solve the problem.

The make/model info is needed to figure if the load is too much.  And, yes, it very well might be, even tho the amp is spec'd to be stable at 1 ohm mono.

You've already seen a difference in performance by making a change in the ground.  For the amp (and most amps, BTW) to perform without fault at the extreme limit of their operating range, all things must be perfect.  Even the subs themselves may result in an impedance that pushes the boundary too far.  Because speakers are never at an exact number of ohms impedance....but are actually rated for impedance over a variety of frequencies.  And one woofer will have a slightly different impedance than another one.

When you run the amp at an easier load (2 ohms), it is more forgiving of the little things that aren't perfect in the overall system.

Thanks stevdart.

My intention in asking is not to give you crap for your brand choices, that happens on other forums.  My intention was so I could look up the amplifier's specifications and see if you were overloading it by your setup.

Audiobahn rates their amps to a 1-ohm load, but it is not uncommon that they cannot actually handle 1-ohm.  Audiobahn - and many other companies - tend to overstate their ratings.  So as stevdart suggests, changing to a 2 or 4 ohm load is a good test - and better for the amp in any case.   Good for you to have found a potentially badground, that could be part of the problem.  Another possible cause is you may have the input gain on the amp set too high.  How did you set it up?

Haha...  DYohn I didn't mean to single you out....but even in your last post you were able to throw a jab at Audiobahn.... In my personal experience Audiobahn is a good company,  who stands by their product.  So what if they have chrome components,  a few extra LED's for show,  or some flames.  Take the covers off the amp, and you may find they have the same electrical components that other companies may use.  Besides,  how much would an LED cost when you buy in bulk?  A penny?  And the chrome?   Probably not a considerable amount more than a painted casing, especially when you assemble the product in quantity.  Besides,  when you pick up a JL audio product,  what do you think you're paying for?  A subwoofer with an internal supercomputer,  or an amplifier with fiber-optic wires, solid gold components, and a bulletproof circuitboard???   Although possible, I don't find it likely at all.  If anything,  you're paying 100 dollars to buy the letter "J",  another 100 to buy the letter "L"  and 200 to glue a W7 badge on ( the word AUDIO is thrown in for free).