Weird way of powering a sub for cheap - quick question.

[tangmonster]

Originally Posted by jimbo1968

This is what I do. My Adire Tempest tubesub is powered by 2x50W amplifier and I've never felt the need to try it with more power.

As mentioned, the only thing missing is an adjustable rumble filter which could be useful to protect your driver in a ported design. This cuts the frequencies below eg 20Hz. You are probably trying to get as low extension as possible, that's why this filter is preferably adjustable.

I am 100% certain ANY commercial amplifier will have a DC blocker cap and 99% of times these will be designed to let input start rolling of at -3db around 20Hz

If anything commercial stereo amps will start rolling off at higher frequencies so you might need to open up your second hand amp and check input capacitor and input impedance to change roll off frequency to LOWER frequency.

[bunshi]

Thanks for the advice (this site if freaking awesome for beginners like myself)

I just wanted to follow up on what I did.

I bought this really old stereo amp for 3$ from a second hand store

It "says" that it's 25 watts per channel, but when I tested it with a multimeter, the best this will put out is about 4 watts.

No good for a sub.

[bunshi]

So, my next idea was to buy a cheap, active sub from craigslist, and just rip the plate amp from it.

I got a Sony SA-WM20, with a 50 watt plate amp for 20$.

Pulled it off and have it powering my 1.6 cu ft vented Peerless SLS 830667, 8" Paper Cone Woofer from Madisound

This strategy is really nice, because I have a nice volume button, and phase control with it.

I'm planing to use the other 4 watt amp to make a little computer speaker system.