hey i just bought a valve amp
link valve
and im trying to figure out how to plug a sub into it seen as it is a stereo amp without a sub out put

My plan was to get a monoblock amp for a sub however im sure how to connect this all up. i was thinking is it possible to get a sound card or some kind of sound device like crossover with multiple outputs which i can then set one out put to go to the mono block and power the sub and one output going to the stereo amp to power the two speakers, it will have to be external and mac compatible seen as its a macbook im using.

thanks

NOTE - Of course, If your subwoofer doesn't have a built-in amplifier you will need an amp for it.

You need a 5.1 channel "external soundcard" that connects via USB or Firewire. (It should play stereo as "2.1", sending the low frequencies to the subwoofer channel.) I found this one: Fire Wave. As usual, it seems eaiser to find these devices for a PC., so you might check your favorite Mac store.


Or, I suppose the "traditional" way to do it is to use an electronic crossover (example*) and a separate amplifier for each frequency band. In your case, you may only need a 2-way crossover (subwoofer/high-pass) and two amplifiers. But, this kind of set-up might be a bit extreme for a computer's audio system...



* This probably isn't the right crossover for you... It's just the first one I found. (I have a similar crossover, and the one I have can only be used as a 2-way plus subwoofer. So, I need two stereo amps One for the low-mid, and one for the highs) plus a subwoofer amp.)

Get a powered sub! Most will have line level outs that you can then feed to your amp.

Good suggestion! You could hook that up to your computer's existing stereo output. You will need to look for a "home theater" or "hi-fi" sub. You probably won't find anything like that in a computer store. (Not all powered subs have a line-level high-pass outputs, so shop carefully.)