How Do I Connect A Subwoofer To This Amp?

[Ruggie74]

Hello,

I'm new to home audio. This is my dad's old amp from the 70's. I bought him a Klipsch powered subwoofer, and in the manual, it says to connect to the "pre-outs" of your receiver. So, I took out the binding posts between the "pre out" and the "main in" (as pictured) and connected the subwoofer to the "pre out" section with an RCA cable. The volume was BARELY audible. Like quieter than a whisper. Did I do something wrong? Volume returns to normal (for the 2 main speakers) when I disconnect the subwoofer and reinsert those binding/bridging posts between "pre out" and "main in". Any help would be very appreciated!

 

[Ruggie74]

Here's some closer pictures of the back.

 

[lovinthehd]

Does your sub have high level (speaker level) connections? What model of Klipsch sub do you have? Otherwise you're going about it okay except you should use some rca splitters to feed the sub off of the pre-out and simultaneously connect the main in with the sub....

 

[Ruggie74]

Does your sub have high level (speaker level) connections? What model of Klipsch sub do you have? Otherwise you're going about it okay except you should use some rca splitters to feed the sub off of the pre-out and simultaneously connect the main in with the sub....

Hello,

Thanks for your help! It's a Klipsch SPL 150 so I guess it only has line-level (https://d2um2qdswy1tb0.cloudfront.net/product-images/SPL-150SW_Back.jpg?mtime=20190220145354&focal=none). I am terribly embarrassed because I don't quite understand what you mean on how that connection is supposed to work. Is there perhaps a picture or diagram you can find that might illustrate what you want me to do? Or maybe you can find the type of cable you're talking about to show me a picture of that? Thank you so much for helping me! One last thing: can I connect the subwoofer to the Tape 1 "Record" section? Is that safe and will that work?

 

[Swerd]

I am terribly embarrassed because I don't quite understand what you mean on how that connection is supposed to work. Is there perhaps a picture or diagram you can find that might illustrate what you want me to do? Or maybe you can find the type of cable you're talking about to show me a picture of that? Thank you so much for helping me!

Your photo of the back of the Akai amp shows two short metal links that connect the left and right pre-amp outputs (PRE OUT) to the left and right main amplifier inputs (MAIN IN). Remove them. The receptacles in this photo are called RCA jacks (female), and they accept RCA plugs (male).

To add the subwoofer while also connecting the PRE OUT to MAIN IN, install 2 RCA splitters, for the left and right channels. They can look like either of these (below). Insert the RCA plug side of the splitter into the PRE OUT jack on the Akai back panel.

Conect one of the splitter's RCA jacks to the MAIN IN jack on the Akai back panel, using a short RCA cable. (Standard RCA cables have male RCA plugs on each end.) And connect the splitter's other RCA jack to the appropriate RCA jack on the subwoofer, with a longer RCA cable. Do this for both left and right channels.

You can find inexpensive splitters and RCA cables (also called patch cords) at Amazon or Monoprice, or other sources. Between the RCA jack/plug variations, and the different cable lengths, it can be confusing.
Splitter Y adapter (first photo)
Short Y cable adapter (second photo)

Here are two examples of RCA cables, one is 1 foot long, and the other is 6 feet long. You should be able find cables long enough to reach your subwoofer.

 

[j_garcia]

Sub will be getting full range signal this way so it will require some tweaking, but it should work. I have done it with a stereo receiver before.

 

[lovinthehd]

Hello,

Thanks for your help! It's a Klipsch SPL 150 so I guess it only has line-level (https://d2um2qdswy1tb0.cloudfront.net/product-images/SPL-150SW_Back.jpg?mtime=20190220145354&focal=none). I am terribly embarrassed because I don't quite understand what you mean on how that connection is supposed to work. Is there perhaps a picture or diagram you can find that might illustrate what you want me to do? Or maybe you can find the type of cable you're talking about to show me a picture of that? Thank you so much for helping me! One last thing: can I connect the subwoofer to the Tape 1 "Record" section? Is that safe and will that work?

Like Swerd illustrated. As to using the tape connection, it's probably a fixed output (i.e. won't change level along with the volume knob).