My klh subwoofer has R&L connections to speaker and R&L connections to amplifier, but my new amp has a RCA cable connection plug-in. Any way I can use the old subwoofer with the new system?

I would check the caps on the power supply. They are rather large electrolytic capacitors that will look like they burst and/or leaking. When these die, the caps ground and the sub will make a loud buzzing sound. If you are handy with a soldering iron you can replace them yourself. Replace them with the same voltage or a little bigger and same with the size.

If the cap. says 16v 4700pF on it, for example, a 20v 5300pF or a 16v 6200mF cap. will work for this application.

Yes, the 10-120 can use a L & R low level subwoofer input. You can get a short 6" RCA splitter adapter from Radio Shack for a under $10. (1 female input, 2 male outputs) Alternately, just plug the subwoofer output on your receiver to just the low level R channel on the KLH sub.

Low level inputs are designed to take signals directly from an amplifier's "sub out" connections. That way the KLH amplifier will use those signals to produce sound and the volume can be balanced between the main amplifier and the sub amplifier using the sub's volume controls. Depending on your amplifier and sub, that is the best way to connect them. However, be careful running the RCA cables since the low levels are more subject to interference. Keep the runs as short as possible and use high quality shielded cables for the interconnects.

This subwoofer is probably powered directly from the amplifier and doesn't have an internal amp. The connections are probably the same type as for any other speakers. And, there are probably additional connections for the rest of the speakers. The connection on your amp is likely an RCA phono plug connector that sends low level signals to a powered subwoofer. To connect a passive subwoofer, one without a built-in amp, the main speaker outputs connect to the subwoofer and are then sent to the regular speakers connected to additional terminals on the subwoofer. You may need an owner's manual for the subwoofer to determine how it should be connected.

Connect front the sub out (single) on the amp to one of the rca inputs on the sub, This will work reasonably well but to make the most from the sub buy a 2 rca to 1 rca cable and use it to connect both rca inputs on the sub to the single output on the amp

I was trying to find an owner's manual or picture of the rear panel of the sub, but had no luck. The subwoofer is a powered type - or "active" speaker. This means it has a built in amplifier. These active subs usually provide for one or both "low level" and "high level" inputs. Low level signals are usually carried by shielded coaxial cables and have RCA type plugs on the end. The low level is also called "line level". This is an un-amplified signal that might be heard on cheap earphones - but that's about it. It is similar to the output of a tape deck, DVD or phonograph. These signals require an amplifier to be heard. If you have a sub woofer output on your receiver or amplifier, you could run a patch cable between the low level input on the subwoofer and the subwoofer output of the amp or receiver. You receiver or amp may call this output "low frequency effects" or similar. The front and rear speakers would then connect directly to the receiver or amp's corresponding connections.

If you lack low level outputs on the amp or subwoofer, you'll need to run speaker wires from the amplifier or receiver's front left and right speaker output terminals to the subwoofer's high level input terminals. High level signals are speaker connections or amplified signals. These are typically connections that accept bare wire connections. The front speakers would then connect to the subwoofer's front left and right speaker output terminals. The rear speakers connect to the amplifier.

I hope this helps - and good luck!

Forget the 4 wire inputs on the sub as you have pointed out. use the low mono input only.this can be plugged into any audio out connections at the amplifier.so it is one rca/low wire from sub to amplifier then plug in power cord and adjust volume as desired.

As I implied earlier, take a clue from the physical style of connectors for both parts of the subwoofer function in the old and new receivers:

RCA connections are for Line Level signal between components only.

The input (bare wire) at the speaker is for AMPLIFIED signal.

You can't just modify one to fit the other and expect magic to happen. Be glad you didn't do it the other way around and modify an amplified (speaker level) outout into a Line Level input. You likely would have smoked that component.

Your subwoofer is a passive speaker, that is, like any other speaker it needs an amplifier. Many subs are self-powered (amp built-in) and they would mate well with the RCA sub output of the receiver.

Get yourself an Active (self-amplified) Subwoofer and run UN-MODIFIED RCA cables to it, according to its instructions, from the Sub Out of the receiver. Or get an amplifier between your receiver and the sub you have.

Yes if your sub will let you do that. It should work fine but it may decrese some bass from your two sat. sperkers.

Check your rca cables they might be loose or not connected to the amp or the radio. Sometimes those rca cable outlets get worn out by being bumped, moved, hooking up and pulling out connectors. Plug in your rca cords and wiggle them on the amp while radio is on and see if the music cuts in and out