DOUBLE HELIX PICKUPThe Double Helix is a magnetic soundhole pickup forsteel string acoustic guitars. It fits soundholes with aminimum diameter of 90mm, about 3.5”.
The pickup features two switches on the base-plateof the pickup:• The PHASE switch allows you to adjust the phaseof the pickup, so the Double Helix will harmonize
with any other pickup that is in your guitar.
• The TONE switch allows you to choose twosettings:
o GLOSS - a fine and bright tone thatsounds very acoustic, hum-cancellingo STEAM - a more substantial and louder
tone generally associated with soundhole
pickups, hum-cancelling
INSTALLATION:

This manual describes the installation of the Double
Helix pickup only.
If you have a Double Helix intended for a
combination system (Pure Pickup, or other pickup)
the cable connection to the endpin jack will varyslightly. For detailed info on cable connection in
combination systems, please refer to the additional
information that comes with your combo system.

INSTALLING THE ENDPIN JACK:

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The endpin hole needs to be widened to ½”
12mm. You can follow the drill instructions
included with the endpin jack, but we highly
recommend that this part of the installation bedone by a professional.
Unscrew the endpin jack’s strap button.
Remove the outer nut and washer.
Determine the thickness of your guitar’s end
block and set the endblock thickness adjustment
nut accordingly. You may have to back off thescrew cap. Once the nut is in place, screw the capback in, either right up against the nut or as far
as it goes, as tightly as possible. This step mighttake a few tries to get the right spacing.
Insert the jack from the inside into the endpin
hole. TIP: a chopstick or something similar helps
to get a hold of the jack and guide it through.
Attach outside washer and nut and tighten.
Attach the strap button. Important: Make surethat the strap button screws in ALL THE WAY
over the outer threaded part of the jack, so that atiny portion of the thread is exposed when thestrap button is tightened.

For ease of pickup installation and pickup cableconnection, we recommend removing the strings.
TIP: If your guitar has string pins, you can put a capoon the 10th fret, loosen the strings and remove thestring pins. You can now pull out the ball-ends, workon the installation and quickly restring your guitar
later.
(If you do not wish to install an endpin jack at thistime, we offer an ENDPIN JACK ADAPTER CABLE,see p. 5)

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INSTALLATION ON GUITARS WITH STANDARDSIZE SOUNDHOLES (ABOUT 4” / ABOUT 100MM):

INSTALLATION ON GUITARS WITH SMALL
SOUNDHOLES (DOWN TO 90MM / ABOUT 3.5”):•

Auditorium size guitars have smaller soundholes
than dreadnaught or full size guitars. The minimum
soundhole diameter needed to fit this pickup is
90mm or a little more than 3.5”•••

Please put a cloth or similar on your guitar top
and lay the pickup on it.
Connect the plug first and secure the cable inside
the guitar.

Loosen the 2 mounting screws on the pickup alittle bit. Insert the pickup in the center of thesoundhole. Move it towards the neck, align thepickup.
Tighten the 2 mounting screws. A lighttightening will be just fine.

•If you have a guitar with a small soundhole you
should first test if you can insert the pickup when
the two mounting lugs are adjusted all the way
down with the two mounting screws. Bring thelugs into the lowest possible position, just before
they would fall out. Insert the low string side of
the pickup first and check if you can drop thehigh string in also. If yes you are fine. If not, youhave to use the supplied long mounting screws
instead of the shorter screws.

•Unscrew the 2 mounting screws and mounting
lugs and remember the up/down orientation ofthe lugs.

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Replace the mounting screws with the twolonger ones (supplied) and screw on the lugs justenough to hold them in place. They must be able
to move around the outside of the lug-slot.
Please put a cloth or similar on your guitar top
and lay the pickup on it.
Connect the plug first and secure the cable inside
the guitar with the supplied cable clamps, seephotos in paragraph above.
Align the lugs as shown below and drop thepickup into the soundhole.

•Align the lugs with the lug slot, pull the screws
up by ½” (10mm) make sure the lugs are inside
the lug slot. Tighten the long screws.
Move the pickup as far as possible towards theneck, align the pickup and tighten the 2 mounting
screws. A light tightening will be just fine.

PICKUP HEIGHT AND POLE PIECE ADJUSTMENT:The pickup is partially internally compensated foracoustic guitar strings, plus it has adjustable polepieces for perfect string-to-string balance.
The 4 wound strings (E-A-D-G) on an acoustic guitar
are typically bronze wound and therefore not as loudas the 2 plain steel strings B and high E. Therefore
the gap between pickup and strings, especially on
the low string side (E-A-D-G), should be as small aspossible.
The pickup comes with a factory adjusted pole-pieceheight setting. When the Low E and A strings arepressed down on the highest fret, the gap between
the corresponding pole pieces and the strings should
be minimal. If it is larger than about 2.5mm (3/32")
the whole pickup should be raised by adding
padding on the underside of the top plate of thepickup. We include two pieces of extra padding forthis purpose: one for bass- and one for treble side.

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There is one piece of padding on each side of thepickup already. However, if your gap is larger that
2.5mm or 3/32" you should add another piece of
padding, especially on the low string side, to bringthis side up as high as possible. Further fineadjustment can be done with the pole pieces.
The padding has a sticky tape on one side, but werecommend wedging the piece in without taping it.
Once the pickup is screwed down the padding will
not move and can still be easily removed ifnecessary.
If your guitar is especially ”flat” you can also remove
the existing pieces of padding entirely.

Players who strum very hard, or use percussive
techniques that would cause the strings to hit thepole pieces, should lower all 6 pole pieces so that
E-A-D-G are flush with the top of the pickup and B-E
are dropped down even lower.
If this does not provide enough clearance, you canalso remove the existing padding on the left andright side of the pickup (see photo above).
Please keep in mind that lowering the pickup also
cuts down on output volume. Even so, you shouldstill have more than enough output signal in theSTEAM setting.

Once this adjustment is done properly, the polepieces should be adjusted as follows:

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Press the low E string on the highest fret (usuallythe 20th) and adjust the according pole piecewith a small screwdriver so it just clears thestring. It should be as high as possible without
hitting with the string.
Do the same with the A-D and G string polepieces.
The pole pieces for the B and high E string need
to be adjusted much further down, with the B
usually a little lower than the high E.
Note: we found that there is a small difference intone depending on which way the slot on thepole pieces is pointing in relation to the string.
We recommend aligning all pole pieces with theslot perpendicular to the strings.

We preset the pole pieces for an average guitarbut, for best results, please fine-tune this on yourinstrument.
Once the above steps are done, you can further
fine-tune the balance by listening to theamplified tone. The higher the pole piece, thelouder the string will be.

5USING THE ENDPIN JACK ADAPTER:USING THE PHASE SWITCH:

We offer an endpin adapter cable so the Double
Helix can be used without installing an endpin jack.
The cable comes out of the soundhole and then thisadapter clips the jack to the endpin on the outside.

If you use another pickup in your guitar already andwant to blend it with the Double Helix, it is importantthat the phase switch on the Double Helix is set
correctly.

You can purchase this cable directly from K&K, orcontact your local reseller.

If you have a Double Helix/Pure Mini combo systemwith the K&K Dual Channel Pro ST Preamp, simply
set the phase switch to the "K&K" setting.

Please note the adapter cannot be used with thecombination system.

If you’re using a non-K&K preamp, or just one
preamp on one of the pickups, determining thecorrect phase setting is a bit more complicated, as
the preamp might reverse the phase of a pickup.
Here’s what you do: when you play both pickups
simultaneously, the combined sound should be
louder and fuller. If it is weaker that one pickup
alone, just flip the phase switch on the Double Helixand you will fix that issue.
When you only have the Double Helix in your guitar,
you have to determine if it sounds better with thephase switch set to the "K&K" or the "reverse"
setting. There is a 50/50 chance that either way willcompliment your guitar/amp system better. Usually
one setting will get you a slightly fuller tone and lessfeedback.