Kortier Harp Pickup Installation Instructions

Kortier Harp Pickup Installation

—Mount pickups at correct distance from string holes:

The goal is to get firm contact without bending the string too sharply.

—Pickups must be firmly attached to a flat surface for good acoustical function, and to prevent rotation.

If string holes are already present, (as when retrofitting an existing harp) mount pickups at a consistent distance from the holes, to maintain string spacing. Fasten top and bottom pickups in place first, and clamp a straight edge between them. Remaining pickups can be positioned against this edge, so that all are in alignment.

On a new harp, first mount pickups with correct string spacing, then drill string holes. No eyelets are needed for the strings, as the pickups carry the downward pressure of the strings, preventing them from cutting into the soundboard.

—After pickups are mounted, solder “hot” wires

(the central wire of each coax) to the common copper connecting wire. It works well to slide the hot wire under copper buss wire and bend exposed stranded wire up and around using a pointed knife or wooden stick. Watch closely to be sure you have wound all strands around the buss wire. Even a single stray strand touching the ground shield can cause a short circuit and your installation won’t work.

Use rosin core solder intended for electronics work.

Heat the connection to get an even flow of solder through the joint.

When all pickups are attached, slide the copper shielding strip under the coax leads. The black vinyl tape insulates the central wire from the shielding copper ground strip. Put a dot of solder on the copper strip under each braided coax shield. Add some solder to the braid itself. Sometimes casting resin has wicked into the braid during manufacture, so be sure the solder will flow into the braid and make a good electrical connection. Using a small pointed wooden stick, lift the copper strip so it contacts each braided shield, and heat the connection to get a good flow of solder between the braid and the copper strip.

—Bring the coaxial cable from the

Fishman preamp up through a small hole in the soundboard, near the end of the buss strip, or at any convenient point along the buss. Solder in a similar fashion, as you did each of the pickups, center wire to the central copper wire and braided shield to the flat copper shielding strip.

Check all connections with a quick acting VOM, one that beeps (makes a sound) when you touch the probes to a common ground. You should be able to touch one probe to the central wire and the other probe to each braided shield without beeping. This tells you that your hot wires are not grounded at any point. Double check by leaving the probe on a braided shield and touching the other probe to another braided shield. It should beep. This tells you that your ground is continuous. Leave that second probe in place and move the first one back to the central wire. It should not beep. And so on...

Connect a 9 volt battery to the Fishman preamp, and plug a standard electric guitar cord into the jack. This turns the power on to the preamp. Plug the other end of your guitar cord into the amplifier of your choice, turn it on, and your pickups should be live. If the harp is not strung up, you can still test the pickups by tapping each one in turn with a wooden stick or your fingernail, right where the string would be contacting the pickup body. You should hear a sound (from the loudspeaker) from each pickup when you tap it.

If the assembly is totally quiet, that is, you hear nothing when you tap, and you have checked your amp and your cord for correct functioning, then you must have a short circuit somewhere. You will have to go back and check all your connections. Occasionally, a point of solder or a wire end will poke through the vinyl tape. Take a thin wooden stick and slide it along under the central wire to be sure this is not happening.

Visually inspect all connections and any that are suspect can be reheated to get a better flow of solder.

Touching the joint with your rosin core solder as you do this adds a little more flux to the joint, this helps.

The pickups are individually tested before shipping, so it is unlikely that a short circuit is within any of the pickups. But if you have exhausted all other possibilities, the quickest way to locate the short circuit is to cut the central copper wire in the middle. Then test again- if one side tests OK then you know that all the pickups on that side of the cut are OK. Go to the other side and cut that section in half. Once again, one segment will probably test OK, tellng you that the problem is in the other segment. And so on until you have isolated the problem.

When everything checks out and all is working properly, fold the buss strip closed. This completes the shielding around the wiring connections so that your harp will remain totally quiet in the presence of electromagnetic interference (preventing hum and static).

Mount the Powerjack wherever convenient, bearing in mind where the cord will run in relation to the player. Also, there will be a good amount of stress on this assembly as the cord is repeatedly inserted and removed. If you are drilling a hole through a thin area of the harp, back it up with another block of wood.

Use as much thickness as the Powerjack will allow, and glue the backing block securely to the inside of the harp.

I supply a block of wood that may be useful to you. If not, the drill size to use is 15/32 inch, slightly smaller than one half inch, and drill through all layers at one go. Tighten all hardware securely, or it will rattle.

That’s it- you are good to go.

When the harp is not in use remove the guitar cord, this turns the preamp off and saves your battery.

Battery life is estimated to be 1,000 hours. You will know it is time to change batteries if the sound becomes less clear and you have to turn your regular amp up further to get normal volume. Or, just put a new one in annually.

Practical information about hum and shielding

Electromagnetic Interference (EMF) is all around us, all the time. This stray electricity comes from various sources- transformers, fluorescent lights, power amplifiers, and so on. The piezoelectric transducers that are the heart of your Kortier pickups output a very small electrical current when vibrated by the string. In order to be heard by your audience these tiny electric currents are amplified tremendously. The electric currents that constitute the EMF are in many cases of the same magnitude. In order to amplify the piezo signals, but NOT the EMF, we need to shield the circuit path. The shield is a metal barrier around the signal path which is connected directly to earth ground. So, when EMF bombards your harp, these unwanted signals are conducted immediately to ground before they get into your musical signal.

The current path from the piezo transducer all the way to the loudspeaker must be shielded, although it is most important at the beginning of the path, where the signals are of such small magnitude. After the signal has gone through several stages of amplification, it is robust enough to mask most EMF, and you probably won’t hear it (depending on how discriminating you are, and how good your sound system is).

The piezo element inside the pickup is entirely wrapped with a copper foil, which is soldered to the metal braid of the output lead, which you solder to the copper shielding strip, which is connected to the shell of the Fishman preamp through the braid of the connecting coax wire. When you plug your guitar cord into the Fishman, the shell of the guitar plug contacts the Fishman shell, and the shielding is continuous. If you experience a hum problem when using your electric harp, it is best to consult with an experienced technician in this field. Hum can creep in through many paths, either through a piece of poorly shielded equipment somewhere in the chain, or by incorrectly connecting multiple pieces of equipment (ground loops). It is a complicated business, but yields to systematic troubleshooting.