Quoted from billsfanmd:
adding a polk sub....are people still alligator clipping to exiting sub or is a method like pinnovaters Stern spike sub board safer?
While at first this might appear to be OK, if the amplifier has a balanced or differential output (and it probably does) - then I would definitely get what's called a 'balun'. I believe most modern pins have this topology. What this means is the '-' (negative) is not at ground potential anymore. So you could potentially be grounding one side of the amp. Not good!
If it's working, then perhaps the sub might have a balun built in. But for next to no money either get pinnovators circuit or get a balun off of Amazon (don't want to steer sales away from Pinnovators, please support them.), and sleep well at night not worrying about it. Adding a balun is the correct method to convert a balanced output (i.e. the amp) to a single ended or unbalanced input (i.e. the sub or a mixer). Balun stands for BALanced to UNbalanced (duh!).
Some of the older pins (i.e. the 90's), one side of the amp's output is grounded (unbalanced or also called single-ended) - a person should be OK doing that with just wires. Of course, it's a high level signal.
Here's a quick SnipIt from a google search that shows the difference, along with what I use. The Amazon one I had to add clips for the internal sub connection and hook up to the sub or mixer using a RCA connector/cable. I even use them on the older pins to prevent a ground loop issues.
I use a cheapie audio mixer and run multiple pins off of a single sub - but I only play one pin at a time. But they are all turned on.
Edit: I do want to add I haven't looked at pinnovators set up - they might be tapping off at a single-ended point. Don't want to mislead anyone that it truly is a balun setup.
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