I remember having a very similar experience when I set up my 5500 (two trips to Radio Shack). Despite the trouble, I'm very happy with the unit. It's well made, it has great features, performs as advertised, and yes, it looks cool!
Panamax 12 volt trigger Hint
Hooked up my new Panamax Max 5500 today . I even bought a 1/8" male to male cable in advance. So I hook it up and the preamp wont turn the Panamax on or off. You know I am not happy. So I call Panamax which only takes a minute to get them on their 800 line , and guess what? the cable I have is a stereo cable with 2 black stripes on it and it won't work. You need a mono cable. Ok so I run over to Radio Shack and there are none in the store !!! Luckily I got a nice guy who had a look in the basement stock room and found one. Now it works great. BTW none of the manuals for the Pre or Panamax explain that you need a Mono Cable! I hope I can save someone a little hassle with this post. PS The Panamax is a real cool well made very hefty 26lbs!