Adding Pure Bass Power To Your System On A Budget

Sometimes you just want more bass. It may be that Daft Punk needs a little more thump or Metallica needs a little more thunderous roar or Nina Simone needs a little more soul. Regardless of why, there comes a point where a little more bass makes the music just a little more.

There is a way to not only get this deep, rich sound in your system, but do it on a budget and do it without splitting your power by splicing speakers together and without purchasing a $500 powered subwoofer.

I am here to show you how.

Here is what you need... (click on the images to see a larger version)

RCA Splitter (Male to Two Females)

RCA Cable (Male to Male)

Your Main Amp with a Passive Subwoofer RCA Output
Passive Output means you use a powered Subwoofer

A second amp.
My amp of choice is a Fisher CA870, purchased second hand for $9.99

A dedicated pair of Subwoofers

Speaker wire

Now that we have all of the needed gear, lets play.

Let's start by talking a little bit about my existing set up, before this experiment.

I already own the main amp (Technics SA-DX950) which powers speakers with 100 watts of power for each of the four channels) and I paid only $10 for the amp at a garage sale. I call it my main amp for two reasons; first, it powers my main speakers, four of them, and second, it is the destination that my other components connect; turntable, television and cassette deck. I already owned the Subwoofers (Sharp CP G20000 Subwoofers which came as a larger set of four speakers; two subwoofers and two mid/tweet speakers) for $20. You can read about my entire existing setup here.

Before this project I ran all six of my speakers from my Technics amp by splicing my subs from my Technics speakers inputs. Yeah, it split the power and doubled the resistance, but it didn't sound bad in any way, shape or form. But, it also didn't sound as great as it could have. Even though there were deep tones my system didn't roar, thump or have soul.

I wanted something more... so I tried this experiment.

In theory, all I needed to add was a second amplifier, some RCA cables and additional speaker wire. Again, in theory when completed I would have 200 watts of stereo subwoofer sound added to my already 400 watt system.

Here is what I did.

I purchased a new amp, a Fisher CA-870 from a second hand store for $9.99.

I already had all the cables I needed (RCA splitter, RCA and speaker cables).

I plugged the male end of the RCA splitter (first photo above) into the single Subwoofer output on the back of my main (Technics) amp (which you can see in the third photo above).

I ran the RCA cables from the female ends of the RCA splitter into the tuner input of my newly purchased Fisher CA-870 amp (four channels @ 100 watts per channel). This delivers a pure bass signal to the Fisher amp... so any speaker plugged into the Fisher amp other than a subwoofer would likely not fair well.

I disconnected my Sharp subwoofers from my Technics speakers and wired them to the A Channel speaker output of my Fisher amp.

I powered everything up and put on Nina Simone.

Suddenly I had soul.

I put on Daft Punk.

Suddenly I had thump.

I put on Metallica.

Suddenly I had roar.

The experiment worked. I had to tweek some of the speaker positions (something I call, sound profiling my room), some volume settings with both the subwoofer output on my Technics amp and the volume setting of my Fisher amp. After about 10 minutes I found the balance I needed for the system and I sat in my chair and enjoyed.

The cool thing about this, is even though the subwoofer output of my Technics amp is passive, meaning it needs an amplified subwoofer, the main volume control of my Technics amp still controls the subwoofer volume, so I don't have to have a separate volume control for my subwoofer volume... it is all controlled from one source. My Fisher amp just allows me to how much bass is mixed in.... once I find that sweet blend of bass to my mids and highs, I don't have to touch the volume control on my Fisher amp again.

Now there are a few warnings I glossed over here in my steps that need to be specifically called out.

In no way, shape or form should you connect any speaker that is not a subwoofer into your second amp (in my case, the Fisher amp). Doing so will likely destroy the speaker's cone.

If you have spliced speakers, like I spliced my subwoofers at the inputs for my Technic speakers, make sure to disconnect the second set of speakers at the splice, rather than just unplugging the speaker. In other words, before you turn on anything, make sure you don't have any speaker wires plugged into your amp that aren't plugged into a speaker. If those two bare wires touch, it can short out your main amp. While most amps have circuitry that won't allow your amp to be damaged if this were to happen, not all do.

DO NOT max out the volume of the second amp (the bass amp, in my case the Fisher amp) at the start of the first test. There is a lot of power happening, so start with the volume all the way down and then slowly turn the volume up. See what your subwoofers can handle, and find what you need, but test it in little increments, definitely not all at once.

But most of all... make sure you have fun.