Passive Acoustic pickups

[copperheadroads]

Mainly for personal use I want to build a passive sound hole pickup for one of my acoustic guitars & possibly for several family members .
I've also have a bunch of Piezo disc that I was planning wiring 2 of them together (placing them under the bridge inside of an acoustic guitar on each side of the pins ) & wired to the jack .
my soundhole pickup would be based on a stack humcanceling design & I have briefly experimented with it but I feel I might need thick ceramic magnets or Neo magnets unless i have the pickup close to the strings .
any opinions or experience would be greatly appreciated

[bbsailor]

Mainly for personal use I want to build a passive sound hole pickup for one of my acoustic guitars & possibly for several family members .
I've also have a bunch of Piezo disc that I was planning wiring 2 of them together (placing them under the bridge inside of an acoustic guitar on each side of the pins ) & wired to the jack .
my soundhole pickup would be based on a stack humcanceling design & I have briefly experimented with it but I feel I might need thick ceramic magnets or Neo magnets unless i have the pickup close to the strings .
any opinions or experience would be greatly appreciated

I have had some good results using the current-based pickup approach. See the thread I started "Low Impedance Pickup Research".

The output impdance will be in the microphone 150 to 300 ohm range depending on the wire gauge you use for the primaary string loop.

I found a neat way to make a temporary mount that does not require any mods to the guitar. Use .125 inch bungi cord wrapped abound the end of the finger board and down under the heel of the neck. Make it tight enough to be secure to hold both the pickup mounted next to it as well as a mini stereo jack to plug a 2 conductor shielded mic cable attached to an XLR mic connector on the other end. K&J Magnetics has some nice 2 inch long by .25 inch wide by .125 thick neo magnets that work good. To obtain a better string balance, look for some .187 inch dia round magnets of various thickness to balance the typically louder B string. Use the thinnest magnet under the B string. Mount (glue) the magnets on a craft stick (icecream pop stick). If the B string is still too loud, drill a hole under the B string in the craft stick and mount the magnet in that hole to put it farther away from the string.

The current transformer CSE-187L works pretty well and when the shield is grounded to the metal transformer frame along with the primary string loop produces a pretty low noise pickup.

I hope this helps.

Joseph J. Rogowski

[fieldwrangler]

I have had some good results using the current-based pickup approach. See the thread I started "Low Impedance Pickup Research".

The output impdance will be in the microphone 150 to 300 ohm range depending on the wire gauge you use for the primaary string loop.

I found a neat way to make a temporary mount that does not require any mods to the guitar. Use .125 inch bungi cord wrapped abound the end of the finger board and down under the heel of the neck. Make it tight enough to be secure to hold both the pickup mounted next to it as well as a mini stereo jack to plug a 2 conductor shielded mic cable attached to an XLR mic connector on the other end. K&J Magnetics has some nice 2 inch long by .25 inch wide by .125 thick neo magnets that work good. To obtain a better string balance, look for some .187 inch dia round magnets of various thickness to balance the typically louder B string. Use the thinnest magnet under the B string. Mount (glue) the magnets on a craft stick (icecream pop stick). If the B string is still too loud, drill a hole under the B string in the craft stick and mount the magnet in that hole to put it farther away from the string.

The current transformer CSE-187L works pretty well and when the shield is grounded to the metal transformer frame along with the primary string loop produces a pretty low noise pickup.

I hope this helps.

Joseph J. Rogowski

I second that emotion.

Bob Palmieri

[copperheadroads]

Sorry guys ,I haven't returned to the thread I've been too busy .
When I find time I will go through the "Low Impedance Pickup Research" thread
thanks .
.

[fieldwrangler]

Sorry guys ,I haven't returned to the thread I've been too busy .
When I find time I will go through the "Low Impedance Pickup Research" thread
thanks .
.

You'll find it to be extremely comprehensive and feature-packed, thanks to Joseph's tireless contributions to this body of work.