I’m sure this is the basest of audio questions, but I’ve never done anything with speaker wire and older amps and so on - all my experience is with 1/4" speaker cables or mic cables.
So my FiL gave me an old amp when he was moving out of his house, and a couple of small speakers which I would like to use with my electric piano. However, because I’m young and foolish, I don’t know how to connect two speakers with the black and red speaker wire inputs to an amp that has only one set of black and red speaker wire outs. Does that make sense? If so, any advice?
Only connect one speaker to one output. Either serial or parallel connections to 2 speakers won’t be good. Sound like you have a mono guitar amp and it only has one output pair?
If so, red or black isn’t important. One wire to one speaker terminal, the other to the other. It’s not like power wiring. And if you only use one speaker, phasing isn’t a factor.
Yes, one output pair. Just to make sure I’m talking about the right thing, each speaker has this set, and there’s one of the same set on the amp. So you’re saying this is designed to only hook up to one speaker? That seems odd.
The bolded information is incorrect, as many amps use múltiple speakers. Also, a crucial first step has been omitted: find out the power handling (listed in watts) and the resistance (in ohms [I can’t do a greek omega, but that’s what you’re looking for]). This should be printed on the back of the amp.
It’s difficult to tell by your description, but it sounds like this a combo amp where the electronics and the speakers are in a single unit, and you’re trying to replace the speakers with whatever speakers you have handy. Mismatched speakers, i.e., mismatched with the amp, can do some damage to the amp. If this is a recognized brand name amp, you’re better off taking it to a shop to have the work done.
The amp says it’s a Realistic brand 80 watt solid state PA amplifier. Here’s an old eBay listing of what appears to be the same item, if you want to see the outs on the back. The speaker(s) I have would definitely not be original to the amp if it came as a set - a quick google search didn’t really give much information. The speakers are 120 watt.
I used to have one of those amps back in the 80’s. I had a couple, in fact, that I used as practice amps for keyboard when I didn’t want to haul my big keyoard rig around. They are cheap and pretty durable, but not the greatest sound.
Notice it has two quarter inch jacks below the speaker wire connecters? Those are speaker outs, and they are wired in parallel.
If your external speakers have bare wires only, then they can in fact be wired in parralel, just your impedence (not resistance) will be halved. Wiring them in parallel will half your impedence. So two 8 ohm speakers will become a four ohm load to the amp.
Make sure if you are just wiring them in, that you send red to the same wire on both speakers, or they wil be out of phase with each other.
Couldn’t resist – out of phase is roughly like crossing the streams in Ghostbusters. Nothing will blow up, in this case, but your audio will have phase cancellation of the two channels’ sound waves. You’ll miss a lot of the audio content, in a stereo recording.
Do I have it right? Or is there a better way to say it? I often phase cancel to try to cut out the “center” spectrum of your average record to hear the instruments better (vocals are usually right in the center of the stereo spectrum). But I’m only a musician, not a professional audio engineer.
Yeah, that’s prettymuch it. since it’s a mono source it wil just do wierd things to the sound depending on where you are sitting and what the sound is bouncing off of.
I assume you’ll be using a ready-made cord to make the connection. Make sure to purchase a speaker cable. Instrument cables can damage your amp, IIRC it’s because instrument cables are shielded.
11811 may be right about multiple speakers connected to a single output, but only if the output was designed for that, and how they are connected (series or parallel) is up to the design and manufacturer. Otherwise, you have an impedance mismatch which can lead to overloading the amp and/or loss of volume.
And if you are using multiple speakers in any layout, phasing is important (you want the cones to all be going out at the same time, or it may sound odd and lose bass).
Say what? How can a shield damage an amp? Most professional road-unit PA systems use shielded cables with 1/4 inch phone jacks at each end (or XLRs).
You can connect speakers with just about any old wire if you’re not going long distances. Plain old 16ga AC ripcord is fine for home installations. Don’t spend your money on “monster cables” or anything touting better fidelity because it’s gold plated.
I don’t know if you two were talking about the same thing – shielded/unshielded balanced/unbalanced TS/TRS cables shouldn’t matter a damn, you’re right. Unless you need long distances or have amazing RF signals, or something.
I use lamp cord for my home stereo, and it’s fine. But that’s different to connecting source to amplifier, right?
I’m still confused if the “electric” piano in the OP is a Rhodes/Pianet/Wurlitzer or more like an “electronic” (i.e., digital) piano, like those made by Kurzweil, Casio, Yamaha, Roland. Not sure it matters, but I was curious.
Right. I guess we have three elements here, not two: an electric piano, a power amp, and some speakers.
Run the piano line out with shielded cable to the power amp line in. Run the power amp speaker out to the speakers using any cable handy, as long as the run isn’t long and the power isn’t humongous.
The capacitance of a shielded cable can have an adverse effect when used on an amp’s output.
Excess capacitance on the output can cause an amp to start oscillating at ultrasonic frequencies. You won’t hear it, but the amp will be consuming and attempting to dissipate a lot of extra wattage, which may end in the death of the amp, as well as overheating the speaker’s drivers which will either kill the tweeters outright or leave them permanently sounding raspy.
Professional gear is much more robust than anything sold at Radio Shack and can usually handle anything you throw at it, up to and including dead shorts.
Neutrik Speakon connectors are starting to take over the world for speaker connections as they can safely handle higher voltages and currents than XLR or phone plugs - the actual connections are protected from human contact, making for one less way to shock a roadie.
