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GK Wireless

It is a wireless cable to connect a Roland GK-x divided pickup to a synthesizer or modeling unit. Seven digital audio channels are transmitted simultaneously; six channels for the individual strings from the divided pickup plus one channel for the normal guitar output.

You can download the user manual here.

Yes, all controls like; Navigation buttons, Volume and Mode switch are transmitted and will work as normal with a 13-pin DIN cable.

It gives the player more freedom of movement. Furthermore, it is more reliable than the heavy 13-pin DIN cable as the cable is prone to bad connections due to wiggling.

As an additional feature the GK Wireless system comes with a footswitch that can switch the output between a regular guitar amplifier and the synthesizer/modeler unit. Now, you can use your synthesizer/modeler as a switchable add-on next to your regular amplifier (stack). This is an ideal setup for live performance.

A receiver will only accept the data packets that were intended for it. To be able to do this the sender and receiver must be paired before first use.

Pairing allows you to simultaneously use more than one GK Wireless system in one room. Paired systems do not interfere with other systems even if they operate on the same frequency band.

Bring the sender and receiver close together. Turn on the receiver and the sender. If the blue leds on front of the sender and receiver are flashing, then they are scanning to connect. Push the pair button on front of the sender with a small pin and wait till the blue leds turn solid. Now the sender and receiver are paired. Next time you turn them on they know each other and will automatically connect.

One sender can pair with only one receiver. If you re-pair with another receiver, the old pairing is lost from memory. However, a receiver can be paired with as many senders as you like, though only one sender-receiver pair can be connected at the time. The receiver is programmed to connect to maximum one sender, otherwise the connection will become unreliable.

The sender uses two standard 18650 (rechargeable) batteries. For safety, make sure to only use protected batteries with a button top.
They are for sale everywhere, just search for "18650 protected" on the internet.

Actual battery lifetime depends on the capacity of the batteries used. The sender consumes less than 500mA, hence when using two 3500mAh batteries the lifetime will be about 7 hours.

Standard replaceable batteries were chosen so that on depletion of power, fresh spare batteries can be quickly inserted. But for safety, make sure only to use protected 18650 batteries!

You can use any power adapter with center negative polarity DC 5V - 20V, 300mA or higher and 5.5 x 2.1 mm plug.
It is recommended to use a 9V adapter as normally used for guitar effect pedals or with the GR-55.

You can buy one cheap on AliExpress.

Unfortunately, you cannot split the power adapter to feed both the synth/mod unit and the GKW receiver. Although, the voltage and polarity are compatible there will be a loud hum due to different ground levels between the devices.

The GKW receiver needs its own power adapter. Any power adapter supplying a voltage between 5v and 20v DC with negative central pin at minimum 300mA is acceptable.

Per channel 24 bit words at a sample rate of 48KHz. This compares to CD quality.

The free 2.4GHz ISM band is used. Numerous coexistence mechanisms are implemented to avoid interfering with, or being interfered by other radio systems, like;

- Adaptive Frequency Hopping
- Forward Error Correction
- Buffering and Retransmission
- Error Concealment
- High quality audio compression

Adaptive Frequency Hopping is dynamic switching of frequency channels during radio transmission. The GK Wireless system uses 4 RF channels and continuously switches between 18 RF channels with 4 MHz bandwidth to find the most robust connection possible.

About 20 meters if there are no obstacles between the sender and receiver.

See Quick Range Test video: https://www.youtube.com/watch?v=uBTU5koh6og

The latency is determined by the sample buffer size and how fast this buffer is read (sample rate). At the given sample rate (48KHz), increasing the size of sample buffer improves link robustness, but also increases latency. Hence, a tradeoff between latency and link robustness had to be made.

latency = sample buffer size / 48KHz

After careful consideration the latency is set to 16ms. None of our trial users were bothered by (or even noticed) this delay. You can easily test if this amount of latency bothers you by just sitting away 5 meters (16 ft) from your amp while playing something. At 5 meters you will experience about 16ms delay.

For most guitarists, especially when playing a synth or modeler, 16ms latency will be just fine and is the recommended tradeoff. However, on request a prototype with a smaller (or bigger) latency can be delivered at the cost (or gain) of link robustness.

The GKW system is expected to work without problems with all guitars and devices that support a GK-3 or GK-2A divided pickup , but not all synthesizers have been tested by BluCoE. As to date, all Roland GR-xx synthesizers should be fine. On the Boss SY1000 sythesizer it does work, but the sound levels for this system are much lower, so you must turn up the volume.

The GKW system carries the CE- and UKCA mark, FCC- and IC id, hence it may be operated in Europe, the United Kingdom, North America and Canada

All cables are included in the product. The standard short 13-pin DIN cable is for the receiver and the 1 meter long  13-pin DIN cable with locking mechanism is for the sender.

The footswitch is optional (select it in the shopping cart). If you do not buy the footswitch the GK Wireless system works in the normal divided pickup mode (like a physical cable).

If you connect a footswitch, you can switch the output of the receiver between normal divided pickup mode and guitar mode. This is useful for live performances where you want to switch between a regular guitar amplifier and a synthesizer.

Note that in some situations you may hear a popping noise when switching depending on the patch you are using.

  • The system is expected to work with all systems that use a GK-3 / GK-2A divided pickup, but it has only been tested with the GR-55. Godin guitars have not been tested, but user reports confirm that they work with the prototype.
  • More than 95% of the GR-55 patches work perfectly fine, without noticeable latency or background noises. However, a very few patches that are already seeking the borders of noticeable latency, might be pushed over the top and some latency may be experienced with fast playing. Also for a very few patches with very high gain a light background noise may be noticeable when not playing. This can be resolved by slightly lowering the gain parameters of the patch.
  • When using the footswitch to switch between regular guitar stack and synthesizer/modeler a (light) popping may be heard, depending on the patch and the connected equipment.
  • The GKW system is designed to co-exist with other 2.4GHz devices, so a fair amount of other 2.4 GHz devices (e.g.  WiFi) in the room will not be a problem. But there are limits, so when there is too much activity in the same RF spectrum, the performance of the GKW prototype may decrease.
  • For some patches you may hear a soft ticking noise when changing the volume.
  • The sender module may get a bit warm, but that is not an issue.

The GKWS is known to work well with Roland GR55, GI20 and GR20. Also with BOSS GP10.

A defective unit will be repaired under warranty if it is returned within 1 year after purchase.
Carry in warranty, so shipping cost is for the warrantee.
Cables are prone to wear and are excluded from warranty.

Warranty is not transferable to new owners.

Return policy:

Your order will be shipped within 72 hours. You will receive a tracking number by email. Transition times depend on the chosen carrier and destination country.

For regular post check https://tracking.postnl.nl
For DHL express check https://www.dhlexpress.nl/en/track-trace

Subsonic Filter

A subsonic filter is mostly used for piezo elements. Mechanical noise is typically induced when using palm muting techniques or a tremolo and this can produce annoying ghost notes. This is a six channel filter module that removes subsonic non-musical and mechanical noise from the output of a 13-pin divided pickup to improve synthesizer tracking and COSM modeling.

You need to open up your GR-55 and insert it in-between the 13-pin DIN input plug and the board connector. It is very easy to install, just re-connect two connectors.


You can also choose to build this yourself as this is an open source solution that is available on the internet. It is the same schematic as used in the GR300 Filter Buffer device. Or you can buy a similar subsonic filter available from RMC.

I don't know if the schema is the same as it is proprietary from RMC. The function and performance is similar though. At least I have received good reviews from buyers.

It depends on the root cause of your noises. The SSF is no miracle solution to remove any noise. You should always start by properly adjusting your guitar. But for the subsonic noises as described it will work just fine.

Make sure that you follow the installation description. First connect all the connectors and then use the Velcro to fix the SSF board to the side of your GR-55.

If it does not work properly

  • Make sure all connectors are pressed in firmly. Possibly, disconnect and re-connect.
  • Make sure no SSF PCB contacts are making contact with the metal casing of your GR-55. The Velcro sticker is made to shield all the PCB contacts exactly.