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Hi all,

A customer of mind got told that it was possible to place two pickup systems in her Larivee (in this case, a K&K and an undersaddle) and use a stereo output jack to manage the two outputs. So far it makes sens to me, but she also got told that she didn't need a stereo patchcord?

Was she told wrong or is there some technique I'm not aware of?

Thanks!

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

To use a dual system to its full potential it does need to be wired in stereo. You also need to use a stereo patch cord, and you also need a preamp capable of handling a dual stereo output (like the K&K Quantum Blender or Trinity preamp). If it is wired in stereo without a stereo patch cord than you will only get the one signal. Also if you don't have the ability to split and EQ the two pickups separately you are going to have a hard time getting a sound that you are happy with.

Tell your customer that she can have the dual system, but does need the stereo patch cord and stereo preamp. She will be much happier with the amount of control she has over the whole system. Whoever told her otherwise must not have much experience with these systems.

Josh

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Josh House

Canadian Luthier Supply
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House Guitars - Custom Built Acoustic Instruments.
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Hi Josh,

Thanks for the quick reply.

I'm happy to see it wasn't me who didn't understand! I assume the person who talk to her about that was thinking about some mounted dual system, such as the Fichman blend, that does the mixing directly on the guitar itself, thus does not need a stereo jack.

Thanks again!

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

If you wired a stereo jack using the tip for ground, the ring for one pickup signal and the stereo lug for the other pickup signal, when you plug in a mono cable both pickups will be sent to the amp. A good idea, not so sure, but it would work. Wired as such there is no way to adjust the signal strength of the two pickups and the one with the greater output will always be louder.

There are systems sold to do what she wants, check K&K's site http://www.kksound.com/acousticguitar.html to see what they offer. If the customer is trying to do the job on the cheap, your best bet would be to add a blend pot http://www.stewmac.com/shop/Electronics,_pickups/Potentiometers/Blend_Pots.html to adjust the outputs. That is a generalization of course, I'm not really versed in piezo pickups. Kind of takes you back in a circle to the systems with a preamp to get the job done right.

By "patchcord" I assume you are referring to a typical guitar cable or instrument cable. If the two pickups are properly connected to a stereo jack on the guitar and then a mono cable is connected...there will be a mixed signal at the other end of the cable. Yes...it will be both pickups....no...it won't hurt anything...no...it won't be stereo. When the K&K comes out of the left and the undersaddle pickup comes out on the right, whether you are on headphones or sitting in an auditorium, the difference in the sound is going to be quite noticeable. It's simply better in stereo.

To get stereo she'll need to use a Tip/Ring/Sleeve cable from the guitar into a direct box of some sort that processes the signal to a line level so it can go into the mixing board at the right level. Assuming she's a stage performer...the best approach would be to go from the guitar in stereo to a small direct box in as short a distance as possible. In other words...the TRS cable is only 6-10' long to the direct box. From the box...a balanced/shielded line can run all the way to the back of the room and into the mixer. The balanced line is MUCH less prone to pick up RF noise. Typically...a soundstage setup includes a 'snake' from the stage to the mixer. The snake is really just a bundle of many shielded cables. The number of lines usually correlates to the number of channels on the mixer. The basic purpose of the "direct box" is to convert the guitar pickup signal to a line level signal and allow for the use of balanced/shielded lines that cover great distances to the mixer.

If she's going to perform in various venues and if she wants that stereo sound (she does)...she'll need a TRS cable and a little direct box. Often the house will even have its own direct box but she shouldn't assume that. They are pretty cheap and it reflects professionalism to have your own if you want a stereo presentation for either a live or recording situation.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Thanks Steven for you input. But my customer does want to ba able to mix the sgnals as she pleases.


Yes I do. English not being my main langage, I might have made a mistake here.


Somehow I doubt that this could work. If one of the pickup signal is connected to the ring (as it should), and a mono cable is connected, shouldn't it automatically ground that pickup signal?

But anyway, as I mentioned, she wants to be able to balance the two signals. So the path we'll go is the one you discribed (a stereo cable with a stereo preamp or DI, or some other mean to mix the signal). Not so much on a stereo basis (like left and right speakers), but more with regards to playing with the tone of here guitar when plugged.

Thanks for the added info Zlurgh.

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

The tip of mono plug that is inserted into a stereo jack will touch TWO contacts of the jack....mixing the two signals. If a TRS plug is inserted, the tip and sleeve contacts will remain isolated....thus you have two channels for stereo.

In light of your further comments...a good solution would be to use a small mixer onstage and have her plug straight into that with a TRS cable. A little mixer is essentially a direct box in this case but it will also do what she wants plus add the ability to send the pickups left and right. A little mixer like this you could probably get for $50. All you have to do is make sure that it will accept a stereo in and make a stereo line level signal out the back that will accommodate the typical snake.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

If you insert a mono plug into a stereo socket (tip,rim,sleeve) you will get whichever signal is connected to the tip, but the signal to the rim section will just be shorted to the sleeve (ground)by the sleeve section of the plug.
You will NOT get a mix of signals.

Exactly ... with a mono cable, you get only whats soldered to the tip .. the ring will short to ground .... it has to. If it did mix, it would be terrible, as the two impedances wont match, and one will overpower the other. But it wont, so dont worry about that !!!!

Anyway, thats what I do with my KK trinity when I dont want the mic, which is most of the time .. just use a mono (typical) guitar cable.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

What Jeff said.

A stereo cable into a Baggs MixPro will do the job nicely (outboard solution), but there are also various onboard solutions if you want to come out of the guitar with a mixed mono signal. Two signals usually sound better than one, provided you mix them correctly and get them correctly phased relative to each other. The Mixpro output is a mono signal, so you won't get L and R, but you don't seem to want that, anyway.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I did something like this for a customer too, basically it's a stereo jack with both inputs wired to its own channel and the customer would need to tweak things on their own preamp. Another customer asked me to do this too but instead he had one of those integrated Fishman acoustic matrix... it has its preamp and jack all integrated into one unit so it wasn't really possible in that case, I basically wired the second pickup and the other pickup he supplied into the fishman acoustic matrix preamp (he was asking for a toggle switch to switch between the two). It worked, but the customer decided he just wanted the soundhole pickup later so paid me to uninstall the whole works and put the soundhole pickup into a new endpin jack instead.

Moral of the story: This will NOT work with any integrated preamp/jack unit!

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
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Hi Tai,

Yes, I know about the Fishman matrix infinity and the fact that the jack and the preamp are one single unit. Thanks for pointing it out anyway.

But in this case, the USP we will install will not have any onboard preamp. Just connected directly to the jack. The mixing will be done on the outside.

_________________
Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)