Volume and tone control

[supro66]

I added a Fishman thin line pickup to my Martin Sigma Acoustic Guitar

Now I want to add Volume and tone controls

What size pots and cap should I use

I guess I can buy it all here

I found this

http://www.guitarnucleus.com/wiring.html

[G._Hoffman]

I added a Fishman thin line pickup to my Martin Sigma Acoustic Guitar

Now I want to add Volume and tone controls

What size pots and cap should I use

I guess I can buy it all here

I found this

http://www.guitarnucleus.com/wiring.html

I'm not 100% sure of your situation.  Fishman never actually had a "Thin Line" pickup, though Martin sold Fishman's older piezos under the name.  The Martin Thin Line was a passive pickup, and the Thin Line Gold was a very early version of the Fishman Matrix Natural I.  The required solution is very different, depending on which one you have.  If you've got an active system (it needs a battery), you would want a fairly low value pot (relatively speaking here), normally about 25kohms (that's twenty-five K, not 250k misspelled). 

If you want to add these to a passive system, I would STRONGLY recommend getting a preamp and adding it after the preamp, because the impedance of piezo pickups is extremely high (10Mohms or higher!  ), which makes them extremely susceptible to signal degradation.  This is why systems with built in preamps are so popular - even a 5-10 foot cable to your external preamp will be enough to pickup all kinds of RF interference, and will noticeably degrade your signal, leading to the duck like quacking and anemic low end of most passive piezos.  In order to do it, you would need to find at least a 5-10Mohm pot, but probably 10-15 times higher (good luck finding that!), and you would have to experiment with cap sizes to find one that sounded good.  (I suppose you could do the math to figure out where to start - I'm not feeling up to it at the moment, but figure out the RC frequency value for, say, a 250K pot and a .047uF cap with a 8K source impedance, and then scale it up to your pot value, and a 10Mohm source impedance.  Not for me, that!)  Even then, you will get MUCH better results by using an active system.


Gabriel

[supro66]

Here is the Fishman pickup no battery
http://www.fishman.com/products/details.asp?id=3
yes I use the Fishman preamp sometimes

My Crate amp CR60 also has a pre amp in it I just push a button


I just want to control the sound at the guitar



I found these all ready made up
I guess they would work
http://www.guitarelectronics.com/product/CPM25-EMGP/Original-EMG-25K-Pre-Wired-Volume-Tone-Controls.html

[G._Hoffman]

I found these all ready made up
I guess they would work
http://www.guitarelectronics.com/product/CPM25-EMGP/Original-EMG-25K-Pre-Wired-Volume-Tone-Controls.html

Nope.  Those would be fine if you had an internal preamp, but without that they impedance mismatch will be huge, and it will sound awful - if they sound at all.  Think of it this way, the source impedance and the pots are creating a voltage divider, and the top half of that divider is the source impedance (10Mohms, or there about), and the bottom half is the pots.  Now, with the cap in there, it complicates things more than I'm willing to do for the internet, but at the very highest you are looking at 25k.  That's 400:1.  But actually its worse than that.  Not what you want.

Honestly, if you want controls in your guitar, the best option is probably to go with a whole new system, something like the Fishman Matrix Infinity (which will sound better to begin with as it is a much better system, and will give you the controls you want).  More expensive, sure, but if you want it to work right, that's the way to go.


Gabriel

[supro66]

I was told not to drill holes in the top because it may crack

I guess I will just have to use the Fishman preamp on my belt

http://accessories.musiciansfriend.com/product/Fishman-Pro-EQ-II-Acoustic-Guitar-Preamp?sku=303131

[G._Hoffman]

I was told not to drill holes in the top because it may crack

I guess I will just have to use the Fishman preamp on my belt

http://accessories.musiciansfriend.com/product/Fishman-Pro-EQ-II-Acoustic-Guitar-Preamp?sku=303131

That would be a fine solution, and it is a pretty good sounding preamp.


Gabriel