ProSoundWeb Community
Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => The Basement => Topic started by: Andrew Henderson on May 15, 2019, 03:58:34 PM
-
Hi all,
I'm working on a custom guitar that will have three outputs. The first is the typical magnetic pickup system, the second is the piezo pickup in the bridge, and the third is a pickup that has an "octave down" output for the lowest two strings. I intend to process the signals separately, which is why it needs the separate outputs (magnetic to guitar amp, piezo to PA speaker or "acoustic amp", octave output to bass amp/preamp).
I'd like to be able to use a single cable to hook up the guitar to my rack, which has the processing gear in it. I don't know of a "TRRS" 1/4" connector, so I'm looking at using a 5-pin XLR output for the guitar. I know I only need 4-pins, bu 5-pin XLR cables and connectors are more readily available if I needed to replace it.
The piezo pickup in the bridge runs through a preamp/pot that runs on a 9V battery. I'm trying to figure out whether there's a way to have the battery automatically disconnect when I unplug the cable (instead of installing another on/off switch that disconnects the battery).
For example, with a regular electric guitar with active pickups, you can use a TRS jack and wire the negative battery wire to the ring of the TRS jack, so that the battery connects to ground when a TS cable is plugged in.
Can you guys think of any way I could achieve similar functionality of battery disconnection with this weird, custom setup? :o
Is there some other connector besides the 5-pin XLR that would provide this functionality?
Thanks!
-
Hi all,
I'm working on a custom guitar that will have three outputs. The first is the typical magnetic pickup system, the second is the piezo pickup in the bridge, and the third is a pickup that has an "octave down" output for the lowest two strings. I intend to process the signals separately, which is why it needs the separate outputs (magnetic to guitar amp, piezo to PA speaker or "acoustic amp", octave output to bass amp/preamp).
I'd like to be able to use a single cable to hook up the guitar to my rack, which has the processing gear in it. I don't know of a "TRRS" 1/4" connector, so I'm looking at using a 5-pin XLR output for the guitar. I know I only need 4-pins, bu 5-pin XLR cables and connectors are more readily available if I needed to replace it.
The piezo pickup in the bridge runs through a preamp/pot that runs on a 9V battery. I'm trying to figure out whether there's a way to have the battery automatically disconnect when I unplug the cable (instead of installing another on/off switch that disconnects the battery).
For example, with a regular electric guitar with active pickups, you can use a TRS jack and wire the negative battery wire to the ring of the TRS jack, so that the battery connects to ground when a TS cable is plugged in.
Can you guys think of any way I could achieve similar functionality of battery disconnection with this weird, custom setup? :o
Is there some other connector besides the 5-pin XLR that would provide this functionality?
Thanks!
The typical plug switch setup involves using a trs jack in the guitar wired so when you plug in a TS plug it makes the connection between the sleeve and ring terminals.
So it sounds to me like you would need another input/output pair on your connector. Two pins jumpered together in the Shell of the connector on the cable would perform the same.
Sent from my Moto Z (2) using Tapatalk
-
Install the battery at the other end of the 5-pin cable? Or just feed some DC from your preamp circuitry back up a spare wire to the guitar. If there's no battery then the battery can't go dead in the middle of a show.
-
Can't you just use the unused 5th pin the same way as R in the TRS jack? Let's say pin 4 is ground, so wire ground to 4, battery to 5 and connect them using a jumper in the connector.
-
Can't you just use the unused 5th pin the same way as R in the TRS jack? Let's say pin 4 is ground, so wire ground to 4, battery to 5 and connect them using a jumper in the connector.
So it sounds to me like you would need another input/output pair on your connector. Two pins jumpered together in the Shell of the connector on the cable would perform the same.
Wow, I was so stuck on figuring out how to put the jumper / battery connector in the guitar that I hadn't even thought about jumping the pins in the cable. Duh! Thanks, guys.
Install the battery at the other end of the 5-pin cable? Or just feed some DC from your preamp circuitry back up a spare wire to the guitar. If there's no battery then the battery can't go dead in the middle of a show.
Another great idea. I hadn't even thought of using external power!
I'll contemplate these ideas. Thanks guys - these are both better solutions than I was coming up with. This is why I come here.
-
Is there some other connector besides the 5-pin XLR that would provide this functionality?
Thanks!
I am no wiring expert, but what about an Ethercon cable? It locks and if the unthinkable happened (the cable breaks with no spare) ethernet cables can be purchased most anywhere, and would work in a pinch (yes not durable but the gig could go on).
-
I am no wiring expert, but what about an Ethercon cable? It locks and if the unthinkable happened (the cable breaks with no spare) ethernet cables can be purchased most anywhere, and would work in a pinch (yes not durable but the gig could go on).
I quite like this idea - being able to run to the local electronics store and have a replacement in-hand is worth having, compared to a one-in-the-world cable where if it breaks, you're pretty much screwed.
Second option would be to have each output on a 1/4" jack, maybe hidden on the back of the guitar, as a backup.
Chris
-
Keep in mind that while 5pin XLR cables are ubiquitous for lighting, many of the less expensive variants, that are readily available, do not actually have all 5 pins wired. Most only have 3 pins wired... so your mileage may vary....
Sent from my iPhone using Tapatalk
-
I am no wiring expert, but what about an Ethercon cable? It locks and if the unthinkable happened (the cable breaks with no spare) ethernet cables can be purchased most anywhere, and would work in a pinch (yes not durable but the gig could go on).
Ethercon to a guitar?
Wow. I don't think that would work for very long.
Don't get me wrong, it's an easy way to get 8 wires somewhere, but it was never meant for stuff dancing around a stage.
The XLR is a more secure and durable connector, no doubt about it.
Chris.
-
Ethercon to a guitar?
Wow. I don't think that would work for very long.
Don't get me wrong, it's an easy way to get 8 wires somewhere, but it was never meant for stuff dancing around a stage.
The XLR is a more secure and durable connector, no doubt about it.
Chris.
If memory serves line6 did it with their modeling guitar over a decade ago.
-
I am no wiring expert, but what about an Ethercon cable? It locks and if the unthinkable happened (the cable breaks with no spare) ethernet cables can be purchased most anywhere, and would work in a pinch (yes not durable but the gig could go on).
That's a nice idea too - I'd have to use one made with shielded/STP CAT5e, since we're talking about unbalanced connections. I don't see why it would function much differently than an instrument cables, aside from the wires being a little smaller. That also gives me 5 extra conductors (since I'd be starting out using 3 plus shield) for whatever future mad scientist projects I get into on this guitar.
I wouldn't be able to use the earlier idea of jumping the wires inside the cable shell with CAT5/ethercon though, so I'd have to either install an extra switch to disconnect the battery or use Scott's idea of feeding the piezo pickup some DC voltage from the rack.
-
Ethercon to a guitar?
Wow. I don't think that would work for very long.
Don't get me wrong, it's an easy way to get 8 wires somewhere, but it was never meant for stuff dancing around a stage.
The XLR is a more secure and durable connector, no doubt about it.
Chris.
This is true it is not meant for dancing around the stage, however considering the outputs, I am envisioning more of Charlie Hunter style performance (not a heck of a lot of moving). I also think the durability, longevity, and the stiffness (or lack thereof) greatly depend on the manufacturer. Not all Ethercon cables are created equal, I have come across some phenomenal ones, and others which I would not trust for a gig.
Also pointedly I have seen more problems with 1/4 jacks failing on stage over the years, compared to ethercon, and yes on many stages I have more Ethercon in the game than there are 1/4 jacks! I have only ever had 2 Ethercons go out on me, one on an old well used cable which I should have retired, which terminated in an RJ45 (no Ethercon) to which I believe was a possible problem, although it tested fine back at the shop, and another when I was looking for a spare IEM loom at a church I work at. Granted most of this could be that musicians tend to buy VERY cheap cables :o ;D ;D
If memory serves line6 did it with their modeling guitar over a decade ago.
This is correct, for the Variax line, released in 2010.
use Scott's idea of feeding the piezo pickup some DC voltage from the rack.
The guitar could be advertized as POE hahaha ;D
EDIT: Also check out the K&K pure mini pickup, it requires no batteries (or power) and uses an external preamp.
-
Ethercon is good enough for catcore boxes!
-
The guitar could be advertized as POE hahaha ;D
Ha!! I laughed out loud.
EDIT: Also check out the K&K pure mini pickup, it requires no batteries (or power) and uses an external preamp.
Good idea, but this is an electric guitar (Telecaster style body). Those are very nice for acoustics though.
-
If memory serves line6 did it with their modeling guitar over a decade ago.
Yes, the Variax uses an Ethercon. Line6 sells a really nice cable that is rugged and very flexible.
-
That's a nice idea too - I'd have to use one made with shielded/STP CAT5e, since we're talking about unbalanced connections. I don't see why it would function much differently than an instrument cables, aside from the wires being a little smaller. That also gives me 5 extra conductors (since I'd be starting out using 3 plus shield) for whatever future mad scientist projects I get into on this guitar.
I wouldn't be able to use the earlier idea of jumping the wires inside the cable shell with CAT5/ethercon though, so I'd have to either install an extra switch to disconnect the battery or use Scott's idea of feeding the piezo pickup some DC voltage from the rack.
Use each pair for one signal. It’ll get you a little more noise rejection. If you make a custom cable there’s no reason you can’t jump one pair together for your switch circuit. Even without a custom cable you can always jump that 4th pair together back in the rack.
-
Before wiring up the guitar, I suggest you take a piece of STP and solder on a couple of 1/4"TS connectors and see what it does to the sound of your magnetic pickups. I am betting that the result is less than stellar tone.
If you need something less obtrusive than a full size XLR5 jack, you could go to a TA5 mini-XLR connector. You can wire them up with star-quad mic cable and get all 5 pins working.
-
Once upon a time I made a guitar cable from a mic cable (soldering two signal wires together to tip, and shield to shield). It didn't work with his pickup, since the shield in the mic cable was not 100% and the cable picked up some interference from radio or something. I don't remember the pickup type, but learned that proper guitar cables have full shielding (conductive foil under braided/twisted shield). I am afraid you won't find multicore guitar cable, so make sure you won't be affected by this problem.
-
Remember that passive guitar pickups are high impedance and very affected by parasitics.
-
The one issue to watch out for using shielded ethernet cable is many only have a foil shield which might not hold up to the flexing when used as an instrument cable. The easy way I see to use the cable for power is to jump pins at the rack end using a punch down type jack.