Works fine BUT- I had same problem as others. One of the RCA plugs broke loose inside when I installed my cables, messing up the master volume.
I’ve got the cables zip-tied at the rear which keeps the circuit board from shorting out.
The RCA cables I used fit very tightly and were difficult to install. From now on when I install cables (to any unit) I will install them onto another device first, like an old CD player to make sure they are not too tight. You shouldn’t have to use so much force that it breaks the unit you are installing them on.
I don’t think it was the fault of the EQ here. Everything about the unit seems to be of very good quality and the EQs performance is great. Clean and clear sound, and the preamp voltage rise really cranks up my amplifier’s output.
I really like this EQs variable sub frequency control. It allows you to change the crossover frequency right from the dash instead of resetting the amp. Works awesome-I can optimize hz values for different music on the fly. It makes a huge difference in dialing in the perfect sound, song to song.
The rest of of this EQs performance is very good too. Master volume, sub volume and f/r fader-all good. The four band EQ boost/cut +/-18db provides a definitely noticeable difference when you dial the controls.
Overall a very good unit. Would purchase again. The variable sub frequency control really gets it done-5 stars.
Update Review 2-25-15
Purchased another S4EQ for another vehicle. Pre-installed my cables onto the old head unit before using them on the new EQ. No problems.
Using the EQ on a sub only signal from my head unit then to an amp. EQ door speakers with a seven band Clarion. Works great. Love controlling volumes AND sub frequency (S4EQ) using three easy to reach dials. No having to read displays while I’m driving.
SSL S4EQ-Spot on. Perfect for a great price. Would definitely use again.