ghost FAQ: Hexpander MIDI Interface
How's the tracking and latency on the Hexpander?
The ghost MIDI interface, called the Hexpander, is renowned for being very accurate, and offers the Traktion tracking adjustment to match it perfectly to Axon or Roland MIDI converters. Check out Burr Johnson's demos with the Axon AX-100, and you'll see the Hexpander's impressive performance.
How should I set my Traktion switch to optimize tracking?
The Traktion switch is a tiny slider switch that has two positions, left and right. Looking at the 13-pin jack with the Traktion switch below it, left is for Roland converters, and right is for Axon converters. If you have a brand other than these two, try both settings and use the one that tracks best.
What do I need to add MIDI to my guitar?
To add a 13-pin connector and MIDI capability to your guitar or bass, you will need:
1) ghost acoustic saddles to fit your guitar or bass.
2) the Hexpander MIDI Interface (includes 13-pin jack and mounting plate)
3) the Hexpander optional components you choose to suit your guitar and playing style
If you want more than one optional component, consider the PK-0440-00 Hexpander MIDI Interface Kit which is made up of:
BD-0440-00 Hexpander MIDI Interface
BD-0540-00 13-pin Output Jack *included*
BD-0515-00 13-pin Mounting Plate *included*
BD-0512-00 Interface Wiring Harness *included*
BE-0111-00 QuickSwitch for MIDI/blend/mag+piezo *optional*
BE-0181-00 Hexpander Volume Pot *optional*
BE-0180-00 Program Up/Down switch *optional*
Ordering the PK-0440-00 kit saves you the hassle of ordering the same parts individually, and offers better value too. You will still have to order your Ghost Saddles, as these are specific to your model of guitar, so they are not in the kit.
If you are installing the Hexpander alone, without the Acousti-Phonic, you may also want:
PE-0182-G0 Mag to pin-7 Harness
This harness allows you to get mag and/or acoustic signal on your 13-pin cable, so you don't need a 1/4" patch cord connected to the guitar. It requires that you add an acoustic volume pot to your guitar. This feature is enabled without the harness when you install the Acousti-Phonic together with the Hexpander
How big is the Hexpander?
The PC board measures 1-5/8" x 1-1/8". With the connectors on, it's about 3/8" high. Piggybacked with the Acousti-Phonic, they are 1/2" high.
What is the value of the Hexpander Volume Pot? Can I use a regular guitar volume pot?
Our Hexpander Volume Pot is a 250K linear (type-B) pot. A 250K audio-taper pot will also work, but mid-volume will not be at mid-scale. You may choose to do this, especially if you are putting the MIDI volume on a stacked pot, because mixed linear/audio taper stacked pots are nearly impossible to find.
Can I install just the Hexpander without the Acousti-phonic? Will I still have the option of a direct acoustic sound?
Yes, you can install only the Hexpander, and you will get MIDI out on a 13-pin jack (hex output, a filtered analog signal). With the addition of the BE-0182-G0 Mag to Pin-7 harness, your mag signal gets delivered to pin 7 of the 13-pin connector. Most MIDI converters have two 1/4" outputs on the back -- one for the MIDI signal, and the other for this pin 7 signal. You can process these signals separately at this point.
How does my magnetic signal get to pin 7 if there's no connection between the mags and the Hexpander?
You will need a little accessory, the Mag to Pin-7 Harness to connect the mags to the Hexpander. (you do not need this if you are also installing the Acousti-Phonic; it delivers the mag signal to the Hexpander) Solder the green wire on the Mag to Pin-7 Harness to the the tip lug your 1/4" jack, the same point where your mag wire comes from the pots. Note that in Hexpander-only installations, the acoustic signal on pin-7 is the raw sound of the piezos, and is not equalized to compensate for the crystal's characteristics. The Acousti-Phonic provides this option, as well as the ability to blend mag and EQ'd piezo.
Can the Hexpander be installed in an eight string (8 string) guitar?
Currently, the Hexpander and most (all?) MIDI converters are limited to six strings. There are two popular workarounds for an 8-string guitar:
1) have two of everything: two Hexpanders, two MIDI controllers, two cords coming from your guitar, and split the systems 4 + 4 strings, or 2 + 6 strings. Expensive, and a bit cumbersome.
2) Install the Hexpander and the Acousti-phonic and have six strings on MIDI, and two on piezo-only. Depending on the music you\'re playing, it may work to have the two bass strings as straight acoustic, and the rest as MIDI.
The Acousti-Phonic, on the other hand, is ready to go for seven strings or more. At eight strings, you have to add a second summing board, which is a small, inexpensive part. The main board can go to ten, twelve, or more strings.
What is the correct order for plugging in the saddle pickups for a four string bass?
G D A E = 2 3 4 5 and adjust the instrument input setting in your MIDI converter
What is the correct order for plugging in the saddle pickups for a five string bass?
B G D A E = 1 2 3 4 5 or G D A E B = 2 3 4 5 6 and adjust the instrument input setting in your MIDI converter
What is the correct order for plugging in the saddle pickups for a six string bass?
B G D A E B = 1 2 3 4 5 6 or E B G D A E = 1 2 3 4 5 6 and adjust the instrument input setting in your MIDI converter
Can I use my active pickups with the Hexpander?
Yes. In the standard Hexpander-only installation, the magnetic and acoustic/MIDI systems exist parallel to each other, but are not connected, so there's no interaction between them.
If there's no connection between the magnetic pickups and the Hexpander, how does the QuickSwitch mute the mag signal?
Boy, you are sharp. Add the Mag-to-Pin-7 harness, and connect the green wire to the tip lug of your 1/4" jack. This is where the mag and MIDI systems interface.
How can I install the Hexpander without routing the body, so I can take it out if I don't like it?
Order a spare rear cover plate, and mount the 13-pin connector in that. It's not an ideal location to plug into a MIDI converter, but it will allow you to return the guitar to original condition should you choose. You may also want to order a spare pickup ring so you can notch that for the pickup wires, and keep your original pickup ring intact. For Strats, you can order a spare pick guard, and put holes in this for the trial version. These parts are not sold by Graph Tech, but are available from most guitar parts retailers.
