Know Your Cables and Connectors
It’s the beginning of 2009, and best wishes for the New Year! A good new year’s resolution for musicians would be to become more technically knowledgeable in the upcoming year. I’m here to help with that goal, so let’s get started. Today we’re going to discuss cables and connectors used in electronic music and in pro audio.
A good place to start is the type of cable used in various applications. There are three major categories of cables used in the music business: balanced microphone cables, unbalanced shielded instrument cables, and speaker cables. One of the biggest problem areas I see in my work is when the wrong cable is used for an application. Now, this usually isn’t a problem with microphone cables, since their XLR connectors are a dead giveaway as to their purpose, and because the only products which utilize those connectors are microphones, direct boxes, mixers, etc. If the plug fits, you’re in business. It’s hard to make a mistake with microphone cables.
On the other hand, it can be very easy to make a mistake and confuse unbalanced shielded instrument cables with certain types of speaker cables. If you utilize the wrong cable for an application in this area, the quality of your audio will suffer and it may even cost you money for the repair of damaged equipment. So, here’s a quick tutorial on the finer points of speaker cables and instrument cables.
First, let’s talk about unbalanced shielded instrument cables. These are commonly referred to as “guitar cords”, because that is certainly one of their primary applications. In addition to connecting guitars to amps, they are also used to connect keyboards, synthesizers, electronic percussion, etc to their respective amplifiers. Shorter lengths are used to interconnect floor effects units (“stomp boxes”) and rack-mounted audio effects processors. They are characterized by their ¼” phone plugs on each end, and shielded cable is used as the audio highway. Shielded cable means that one conductor is concentric, or wrapped, around the other conductor. The problem is that many speaker cables also utilize 1/4” phone plugs on each end – the difference is that speaker cables use unshielded cable. Unfortunately, it may be hard to distinguish between the two, and therefore easy to use the incorrect cable for an application.
What happens if you should use a speaker cable to connect an instrument to an amplifier? In a word – hum, and lots of it. Cables which connect to the inputs of amplifiers (or interconnect devices which then in turn connect to the inputs of amplifiers, such as effects units) need to be shielded cables. Generally, no damage occurs should you inadvertently use a speaker cable in place of an instrument cable (unless you have the volume on the amp set so high that the hum is overpowering and damages your speakers before you can power down the system).
But what happens if you use a shielded instrument cable to connect a speaker to a power amplifier or powered mixer? This is especially bad, because there are no immediate telltale clues that you’ve done anything wrong. The speakers will work – but, unknown to you, there will be considerable signal loss in that instrument cable. Instrument cables use conductors that are quite thin, because they are designed to carry only a very small signal, and don’t really need to be very large. When used as speaker cables, you could easily be losing 10% to 30% of the output power of the amplifier in that instrument cable. Where does the power go? It is dissipated in the form of heat within the cable itself. Heating the cable actually increases the resistance of the cable, which in turn increases the signal loss – a vicious cycle. You will be setting your mixer and amplifier volume “by ear” to get the right sound level in the room, and so you will be turning up the level even louder, forcing more power through the cable. Now you have another vicious cycle on your hands. You may not even realize that you are running your equipment nearly wide open to achieve a decent volume in the room. Your PA system itself is running very warm, cranking out the watts that you are demanding that it deliver. Sooner or later, something has to give. The cable may melt down internally, causing a short circuit on the output of the amplifier. Or, the power amp or powered mixer itself may fail from its own overheating. Either way, your gig may be suddenly interrupted by the loss of audio, and you’re going to be out some big bucks for the repair.
If your PA system uses 1/4” – 1/4″ speaker cables, be absolutely certain that the cables you have for that application are indeed speaker cables, and make sure you do not intermingle them with instrument cables. I need to clarify one point on this issue. If you have powered speakers (speaker cabinets with a built-in power amplifier, meaning that the speaker cabinet must be connected to 120V AC in order to operate), then you should use instrument cables to run the output of your mixer to the powered speaker. This is a low-level signal, and the powered speaker requires shielded cable to its input. A better choice is an XLR-XLR microphone cable, if the powered speaker features an XLR input, and if your mixing board has a balanced XLR main output.
Today, many newer systems have eliminated the use of 1/4″ - 1/4″ speaker cables in favor of other types of connections. This is a definite improvement, as it eliminates the possibility of error in grabbing the wrong cable. Plus, 1/4” connectors were never designed for the amount of current needed by today’s high wattage systems. Here are some other types of connectors found on speaker cables today:
Speakon is a type (and brand) of multi-pin connector developed by Neutrik which is commonly found on speakers and amplifiers with high wattage ratings. Speakon connectors offer a very reliable connection, can handle extremely high power, are very durable, and are relatively low cost compared to other connectors.
A banana plug is an electrical connector designed to join audio wires such as speaker wires to the binding posts on the back of many power amplifiers or to special jacks called, of course, banana jacks. A common configuration of banana plugs is to have two of them molded together and spaced 3/4″ apart, which is also the spacing of the binding post receptacles on the back of power amps. Technically this assembly is referred to as a “double-banana” plug. An advantage of banana plugs is the relatively large metal surface area used for the connection, which virtually eliminates signal loss at the connection point. Disadvantages include the ease in which the plug can accidentally be reversed (turned over), causing speakers to be out-of-phase with each other. Also, the banana plug can be easily pulled out of the banana jack should you accidentally yank or trip on the cable on stage.
Bare wire is the most basic (and least recommended) way to connect audio. It consists of dual-conductor cable, stripped of insulation at the ends to expose the individual conductors. These can be inserted into binding posts or hooked around screw terminals that are then tightened down. Besides the general “messiness” of bare wire, you must always make sure to match the “hot” and “ground” conductors of the cable on the outputs of the amp and the inputs of the speaker to prevent phasing problems. We don’t recommend this type of connection other than in an emergency.
Some systems require a combination of these connectors, so a hybrid cable is needed. For example, your power amp may have banana jacks only, and your speakers have Speakon connectors – in this case, you’ll need speaker cables with banana plugs at one end and Speakon connectors on the other end. The good news is that with these type of cables, you’ll never inadvertently connect an instrument cable in place of a speaker cable – the connectors won’t fit.
Finally, what is the best type connector for speaker cables? I would enthusiastically recommend Speakon connectors at both ends, if compatible with your equipment. Speakon connectors have good contact area for minimal loss, are twist-lock by design so they can’t be accidentally disconnected, and are durable. Definitely a good choice for the new year!
Frank the Tech Guy
February 14th, 2009 at 1:45 am
Just want to touch base with a question for you. I just purchased a 100watt Krank Krankenstein amp and like an idiot I accidentally connected the head to the cab using a guitar cable on only one of the outputs (lower cab). I didn’t notice anything wrong sound wise other than it being a bit dryer than I though it would sound. That maybe just be the particular tubes that came stock..? At any rate, I’m glad I noticed it when I did and I switched it out immediately.
MY QUESTION is this…… Do you think I hurt anything? OR, since I didn’t get the master volume up but only half way and do not notice anything wrong would you say I’m safe since I caught it within about 30 min into playing? The head sounds killer other than needing to work on the tone and depth a bit. I think I’m safe, I just want to be 100% and hear it from a professional.
Thanks for your time and consideration.
Cheers~
February 15th, 2009 at 12:53 pm
Dustin,
It sounds like your amp is fine. Any damaging problems caused by the guitar cord being used as a speaker cord would have shown up while you were still using it. What can happen (especially if you had been cranked up loud and pushing a strong signal to the speakers) would have been that the cable would have overheated resulting in insulation failure. You would have then had a short circuit across the output, which could have potentially caused some damage to the output transformer and output tubes unless the power fuse had blown quickly enough. Fortunately, the guitar cord didn’t fail completely, and you came out OK. A good suggestion would be to develop some way to identify your guitar cables from your speaker cables, to prevent this type of thing from happening again.
Best Regards,
Frank the Tech Guy
May 19th, 2009 at 9:16 pm
I recently was jamming on my guitar and the guitar cable suddenly stopped working. I KNOW it’s not the input because i tried a different guitar and it didn’t work either. Plus, when i used a different cable everything worked just fine. So my question is…how did the cable short out??? Or did it??
May 20th, 2009 at 7:25 pm
Justin,
Guitar cables are somewhat prone to failure because the center conductor in the shielded cable is fairly small, and therefore it doesn’t take a lot of handling to cause it to break. The most common failure is right as the cable enters one the 1/4″ plugs, because the cable is often pulled and flexed sideways at that location. Just as you can break a wire coat hanger if you bend it back and forth repeatedly, the flexing of the cable at the connector entrance into the plug eventually causes it to fail. Recommendations: Always have a spare cable. And, purchase good quality cables - cheap cables fail more often and more quickly than quality cables. A good quality 20 ft. guitar cable runs about $20, give or take.
Frank the Tech Guy
August 25th, 2009 at 2:28 pm
Hey Frank, was hoping you could help with a PC studio set-up. I need help with a basic set-up to hear and record my electric guitar. I will also be using a DAW to record and NOT the Portastudio. My prior set-up was guitar into a Tascam Portastudio MKII using the 1/4″ LINE INPUT, then RCA from LINE OUT into LINE IN on my PC (Dell) sound card. Then RCA MONITOR OUT from the Tascam into a Technics Stereo Integrated Amplifier (SU-V98) MAIN IN and speaker wire to Celestion 5 MkII’s (8 Ohms, 10-90W). This worked ok, but I was upgrading my PC and thought a new sound card would give me better results and I also wanted balanced connections. Now, I have a new PC with an M-Audio Audiophile 192 that uses TRS exclusively for balanced connections. That great but I don’t know how (or if) I can use my Tascam anymore due to it’s (seemingly) limited connections. It is an older board that records to cassette and I do have the manual I could scan and email. I’m not really familiar with all of the Tascam’s connections and I’m kind of getting frustrated with the best way to go with my set-up and wondering if I need to ditch the passive monitors and go with actives, or maybe use a powered mixer due to the unbalanced Celestions, and of course, if I should forget using the Tascam anymore and look into a new mixer. I will list all of the Tascam Portastudio and Audiophile connections:
TASCAM: 1/4″ (4) MIC/LINE INPUT (1-4)
(4) LINE INPUT (5-8)
(4) STEREO INPUT (9/10 11/12)
XLR (2) MIC/LINE INPUT
RCA (DUAL) (1) LINE OUT
(1) MONITOR OUTPUT
(1) 2TR OUTPUT
(1) SUB INPUT
(SINGLE) (1) CUE OUTPUT
MA 192: 1/4″ (2) INPUTS
(2) MAIN OUTPUTS
(2) MONITOR OUTPUTS
Stereo S/PDIF inputs/outputs on RCA coaxial connectors
I appreciate any help and advice you could give me on getting my sound up and running.
August 25th, 2009 at 8:04 pm
Hi Mark,
You’ve got an excellent PC sound card in the M-Audio Audiophile 192. In order to realize its excellent capabilities, however, you need to ditch the Tascam Portastudio.
First, you have a new PC sound card with incredible signal-to-noise ratio and dynamic range - connecting that to a cassette-based multitrack takes you back to ground zero. Cassette technology has very limited dynamic range and terrible S/N ratio by today’s standards. Plus, you’ll be connecting your new balanced sound card to the unbalanced Tascam - although not a terrible sin, that does allow for increased 60Hz background hum in your recordings. One of the basic rules of audio is that the quality can be no better than the weakest link in the chain. So, upgrading your sound card, etc, does nothing for you if you still use the Tascam - your sound quality will not improve at all over the standard PC sound card. I say that because the S/N ratio and dynamic range of your plain vanilla sound card still exceeded the S/N and D/R of your Tascam. So, the Tascam was and still will be the weakest link in the chain. If it’s in good working order, I would recommend retiring it or offering it on eBay, and find a digital replacement unit with balanced inputs and with hard drive recording and CD burning capability, and USB ports for recording to flash drives.
Powered monitors offer no advantages to your existing configuration, other than a more compact foot print and less cables to fool with. If your existing monitors sound fine to you, keep them along with your power amp.
Hope this helps -
Frank the Tech Guy
November 24th, 2009 at 2:43 pm
Hi Frank, had a question regarding 1/4″ mono and stereo (TSR) cables.
1) Are the line-in jacks on mixers for 1/4″ mono cables. I know that instrument 1/4″ cables go in fine, but I sometimes use these line-in jacks for music from a laptop. So from the laptop the connectors is an 1/8″ stereo, so does the 1/4″ connector need to be mono (with one stripe)? I’m assuming that it does since I notice when a 1/4″ TSR cable (2 stripes) is plugged in, I only get one signal from the stereo signal, usually the music.
2) If this is the case (where the 1/4″ cable needs to be mono and the 1/8″ cable needs to be stereo), then is the best cable to get (for my purposes) is a 1/8″ stereo to an RCA Y-cable and a RCA-cable to 1/4″ mono adapter?
3) For recording, does the Aux send from a mixer output mono? If that’s the case, then am I right in saying that recording with the cable mentioned above is the right cable to use? Because I’ll be outputting to a 1/4″ mono and going into my laptop with my 1/8″ stereo connector. I’m assuming that should be OK, but that’s the assumption that my macbook pro’s recording 1/8″ jack is stereo.
Any comment would be greatly appreciated!!! Thank you!
November 24th, 2009 at 8:34 pm
Dennis,
The 1/4″ jack on all mixers is a mono connection. Now, some mixers do have a T/R/S jack, but that’s not for a stereo connection - that’s for a balanced mono connection (where the signal appears between the tip and the ring terminals on the jack, and the sleeve is just used for shielding only). But don’t let that confuse the issue - if you just a Tip/Sleeve plug into that jack, you ground the ring conductor, and your signal is between tip and sleeve - once again, just a mono connection.
To use the output from a sound card on a PC, which as you indicated is a T/R/S stereo connection, you have two choices. You can get a 1/8″ plug to dual RCA plugs (the Y-cable) and then use two single RCA jack to 1/4″ plugs and run each 1/4″ plug into a separate channel of the mixer (let’s say channel 1 and channel 2). If you have a stereo mixer (with L & R separate outputs), you can then pan channel one all the way to the left, and pan channel 2 all the way to the right, adjust the levels of those two channels appropriately, and then you will have the true stereo mix from the PC.
Or, as you say, you can get an adapter that combines the two RCA plugs into one mono 1/4″ plug, and just use one channel. Of course, you have combined the two stereo channels into one channel, and your mixed signal is now just mono. If it’s a mono mixer, this would be all that would be needed, as you can’t get a stereo mix out of the mixer anyway.
The aux send from a mixer is indeed mono. To get a stereo signal to go back to your PC for recording, the best way would be to pan various channels mostly left, mostly right, or dead center for mono, and then go from the left and right main outputs through a stereo Y to 1/8″ plug to the input jack of the PC. By controlling how you set the pan on each channel, you control the stereo mix. It’s best not to pan all the way left or right, or that particular instrument or vocal will only appear exclusively on the one side of your stereo mix. They made recording that way back in the 1960’s when stereo was in its infancy (some Beatles songs were recorded that way), so that if you listen to the left channel you have acapella singing, and the right channel is strictly instrumental (a la Karaoke).
December 3rd, 2009 at 8:40 am
Hey Frank,
I always make my own instrument cables from Canare GS-6 and Neutrik connectors. I already made few cable sets, and I got a bad one. This one is dull, the high frequency is just lost. I redo the solder and cut the lenght by 5-7cm, but it’s still not working. Is there anyway to know where exactly the bad spot from the cable ? So I can cut it, and use the remaining length.
Thx
Abner
December 3rd, 2009 at 10:09 am
Abner,
That’s a common problem when a cable develops a fault in the cable itself.
There’s no simple way to determine where the fault lies (unless you can go
through the cable flexing and bending it and discovering that you can clear
the fault temporarily by flexing the cable at a certain point).
Otherwise, you’ll need to cut the cable at the halfway point, and test each
half. Assuming that there is only one fault, you’ll wind up with one good
cable and one bad cable, each half the length of the old one. Once you
determine the bad piece of cable, you could go ahead and cut it in half
again and check both of those pieces. Theoretically, you could wind up
with 2 good pieces of cable, one half the length of the original, and
another one that is one-quarter the length of the original. Hopefully you
can use some shorter patch cables.
Frank the Tech Guy
December 6th, 2009 at 6:02 pm
Hey Frank,
Finally have an Alesis RA-100 power amp for my passive Celestion 5 monitors. Right now, they are just connected with bare wire and that is working fine, however, I would like to have use permanent connectors. The RA-100 also has 1/4″ OUT and the Celestions use binding posts with round, removable heads spaced too far apart for dual banana jacks. I would like to use the 1/4″ OUTS if possible, since the others ones I’m using on the RA-100 are wire push tabs. Any ideas? Thanks, Frank.
February 4th, 2010 at 11:14 pm
Hey Frank, just wanted to ask a couple more questions in reference to Dennis question about 1/4″ mono and stereo (TSR) cables. I have a cheap Behringer mixer xenyx 802, which i want to use to connect my roland sp 404 which has RCA outs, my Korg electribe esx (which has one set of 1/4 inch outs) and my zoom sampletrak (which also has a set of of 1/4 inch outs) and a korg microkorg. I would be running my turrtables through the line of my esx into the line of my sp-404 into the stereo channel 3 of my mixer then run my microkorg into the line of my zoom sampletrak into the other stereo channel 5 of my mixer . Lastly my mixers outs would be running into my tascam dp01 8 track recorder to record.
So now you know my setup my questions are
A) is this a harmful signal flow and is this possible on my mixer.
B)what cables would best link all these together to make sure that they are all coming into my mixer in stereo
C) This might be a stupid question, but if you plug mono 1/4 inch into the appopriate left and right out and ins would this achieve stereo, so in other words can you achieve stereo by using to mono 1/4 cords or would i better off using using stereo 1/4 inch into both left and right outputs of my samplers
Thanks for taking the time do answer my questions, this issue is giving me a headache and i want to make sure im using my setup the best way possible, a little hiss isnt too bad for me , since i make mostly lofi tape music any way