Rookie question: What happens if you plug a TRS (stereo) cable between your bass and amp?

Spectre Gunner

Spectre Gunner

Jun 8, 2016
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#1
I just built a TRS cable, you know the kind with three wired connections on an instrument plug instead of the typical two wired (mono) contact points on a 1/4" plug?

I built the cable to enable a two button pedal switch (the original BeatBuddy Footswitch Pedal) to allow the amp to either mute and/or activate the Mid/Cut circuit with either one of two buttons. It works as it should, however...

But now that I made this cable and added it to my cable collection it got me wondering what would happen if I accidentally used it in the wrong place? This pedal works as it's supposed to now that I have a working 10" TRS stereo cable. However, is there any danger to my amp if some "helpful person" plugged this TRS cable between my bass and the amp?

The amp is an Epifani 555 1000w Piccolo going into an Epifani D.I.S.T. 112 Cab and with with various passive/active basses.

I thought I'd ask the TB experts before I learn a lesson the hard way, again.
 
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#2
Yeah, I see the problem in my head.

Mainly, it’s a shielded cable. With either one or two conductors. It’s not speaker cable.

So trust me, don’t let that cable come between your amp and your speaker cabinet. And don’t let a helpful person set up your rig.
 
#3
It depends on what the amp manufacturer uses the ring terminal for.

For example, I always use a TRS input jack and float the ring terminal, this makes it pretty universal, but some amp designers use the ring terminal for other functions, or to control things inside the amp by telling the circuitry that something has been plugged into the input jack. This is done when the tip switch is being used for some other internal function.

This kind of thing becomes an issue when a jack is used in a way that it was not designed to accommodate.
 
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#4
The typical mono instrument cable we use is also a shielded cable. It's like the coaxial cable that's used for cable TV with a braided shield on the outside of the jacket and a center wire in the well center. The difference with the stereo wire is that it has two center wires with an external braided shield. They're all insulated of course.
 
#5
trs1.gif
TRS
TRS is the abbreviation for “Tip, Ring, Sleeve.” It looks like a standard 1/4″ or 1/8″ plug but with an extra “ring” on its shaft. TRS cables have two conductors plus a ground (shield). They are commonly used to connect balanced equipment or for running both left and right mono signals to stereo headphones. You will also find TRS connectors on the stem of Y cables. These are used for mixer insert jacks where the signal is sent out through one wire and comes back in through the other.

ts21.gif
TS
TS is the abbreviation for “Tip, Sleeve” and refers to a specific type of 1/4″ or 1/8″ connector that is set up for 2-conductor, unbalanced operation. One insulator ring separates the tip and sleeve. The tip is generally considered the “hot,” or the carrier of the signal, while the sleeve is where the ground or shield is connected. TS cables are best known as guitar or line-level instrument cables.
 
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#6
Well, I bought a new bass a few months back and had a problem with it simply not working when I plugged it into my bigger rig, even though it worked just fine in my practice room. I started a rather embarrassing thread about it because I did all sorts of troubleshooting and could not figure out the problem, which turned out to be a TRS cable that I'd picked up by mistake. Which worked just fine with my other bass, but not with my new one. So what *could* happen is... nothing.
 
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#7
Geri O said:
Yeah, I see the problem in my head.

Mainly, it’s a shielded cable. With either one or two conductors. It’s not speaker cable.

So trust me, don’t let that cable come between your amp and your speaker cabinet. And don’t let a helpful person set up your rig.
Click to expand...

But yeah, it's definitely not a speaker cable. Just a 3 wire instrument cable. I just don't want to take a chance that it would short something out and blow my amp.
 
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#8
LBS-bass said:
Well, I bought a new bass a few months back and had a problem with it simply not working when I plugged it into my bigger rig, even though it worked just fine in my practice room. I started a rather embarrassing thread about it because I did all sorts of troubleshooting and could not figure out the problem, which turned out to be a TRS cable that I'd picked up by mistake. Which worked just fine with my other bass, but not with my new one. So what *could* happen is... nothing.
Click to expand...
Yes, it can. In your case, the manufacturer of the bass probably used the ring terminal to close the ground of the on-board power (active bass , right?) to turn the bass on.
 
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#10
Spectre Gunner said:
But yeah, it's definitely not a speaker cable. Just a 3 wire instrument cable. I just don't want to take a chance that it would short something out and blow my amp.
Click to expand...
Re-read my explanation, I answered your question.

No, it probably won't blow up your amp, but may not work properly with your amp or other equipment.
 
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#14
Using a TRS shielded cable in place of a TS shielded cable may cause no problems, or lots of problems, depending on the topography of the circuitry in your bass and amp. As @agedhorse said above, sometimes the "electrically floating" ring won't activate the preamp in your bass.
If your bass is passive, and your amps input doesn't incorporate switching circuitry, then the TRS will work just like a standard TS cable.
Look at those photos above.
Electrical contact on a passive bass's jack is made at the tip, and at the base of the sleeve. Same thing at the other end with most amps. (Again, most amps!) There is no contact made at the ring at either end, so it's as if it doesn't exist. No problems.
Throw in an active bass, or an ambitious amp, and all sorts of gremlins can ride in.
In other words, you would do well to heed the advice of the Old Pony above!
 
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#15
Spectre Gunner said:
View attachment 3330476 TRS
TRS is the abbreviation for “Tip, Ring, Sleeve.” It looks like a standard 1/4″ or 1/8″ plug but with an extra “ring” on its shaft. TRS cables have two conductors plus a ground (shield). They are commonly used to connect balanced equipment or for running both left and right mono signals to stereo headphones. You will also find TRS connectors on the stem of Y cables. These are used for mixer insert jacks where the signal is sent out through one wire and comes back in through the other.

View attachment 3330477 TS
TS is the abbreviation for “Tip, Sleeve” and refers to a specific type of 1/4″ or 1/8″ connector that is set up for 2-conductor, unbalanced operation. One insulator ring separates the tip and sleeve. The tip is generally considered the “hot,” or the carrier of the signal, while the sleeve is where the ground or shield is connected. TS cables are best known as guitar or line-level instrument cables.
Click to expand...
Great post!
 
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#16
The wire gauge/sheathing of your manufactured cable may not be sufficient to carry the current that the amp delivers to the speakers. At full power, your 1000W@ 4 ohms have a current of about 16 amps and 11 amps for 8 ohms. There should be a safety factor in the cable spec allowing it to handle more current.

I would attach a label on each end of the cable to identify it's intended purpose.
 
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#17
In an ideal world one would have only speakon connectors on cabinets so it was impossible to connect up jack cables. Trouble is I have a bit too much legacy kit, it would cost a fair old lump to convert all the cabs and cables. If you haven't got that much kit though it would be well worth doing.
 
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#18
I guess it depends how you define a fair old lump. I've bought connectors and converted my 1/4" stuff to Speakon. ...about $10 / cable, and that's for the real Neutrik stuff. I guess that could add up, but it's been trouble-free and worth it so far. ...certainly cheaper than replacing them.
 
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#19
I’ve done that as well. Drilling a hole in a cabinet to mount a speakon would turn some people off. Sometimes it isn’t so easy, it depends on the cab. But what you gain is well worth it.
 
#20
Spectre Gunner said:
it got me wondering what would happen if I accidentally used it in the wrong place?
Click to expand...
although you are looking for 'certainty' because you want to be 'safe' you are likely to get one of two possibilities if you use a TRS cable instead of a TS cable = either it will pass a signal as you expect or it won't.

if you made the cable correctly = you will not blow anything up even if it is accidentally used in the wrong place. if the cable is incorrectly wired = you will not blow anything up, but it won't work as expected.

good luck with your cable worries! :thumbsup:
 
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