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      How To, Nu Series, Pickups

Audio_mixer_fadersHow do you wire the Neos?

The initial release of the Neo series polyphonic pickups was for DIYers, serious hackers and guitar builders. The Neo is not your typical pickup. You can’t install it just like any other pickup. It is polyphonic and requires more work to set-up properly. In Cycfi’s FB page, Steve Hodge comments: “A full system would be excellent. I love the concept but have no idea how to hook it all up”. Soon, we will provide support infrastructure such as breakout boxes, controls, and multi-pin cables and connectors to make it easier for anyone to use the pickups.

In the meantime, for those who are adventurous enough, it’s really not that difficult. You don’t really need an elaborate setup to get into polyphonic string processing.

Allow me to reply to an email from Sam Park:

Hey Joel, so I have one question about the Neos. Now I’m no professional hacker by any means, but any regular maintenance or fixing that a guitar needs is something I can manage. I’ve had my share of swapping pickups and so the process is no mystery, but I have not ever made or taken an active pickup apart.

It looks like the Neos is something that requires some building to be done. My question is how much building?

Is it difficult to learn to install the Neos to the point I would have to take them to a professional?

Basic Setup

Before anything else, always refer to the Neo Data Sheet.

The easiest, most flexible, and cost effective way to get into polyphonic processing is to hook up the Neos digitally to a Digital Audio Workstation running multiple audio effects plugins —one per string. All you need is a laptop, a multi-channel audio interface and of course software. You’d probably have all these already! Then, all you have to do is find a way to connect the Neo’s individual outputs to the audio interface. There are many ways to do that, from the simplest to the most elaborate. I’ll illustrate some basic ideas and move on to more elaborate schemes in future installments.

connections

 

Audio Interface

All processing is done in your Laptop. A Digital Audio Workstation (DAW) such as Apple’s Logic Pro, MainstageAbleton Live or Cubase will be your main tool for multi-channel processing. Each string goes to a separate channel (or track) where you can insert various effects. It’s amazing how software based effects plugins have matured in the recent years. These software effects have become quite powerful and fast, especially when using multi-core CPUs which are more or less the norm these days. Effects plugin software such as Guitar Rig are remarkably convincing in emulating various stomp-boxes, amplifiers, speaker cabinets, etc. You can have as many effects as you want limited only by your computer’s processing power.

What audio interface should you use? Well, you need to have at least 6 inputs (more if you have a 7 or 8 string guitar, less for 4 string bass). Latency is also a big issue. You need the interface to be usable in real time. Get one with minimum latency. Here’s a good list of recommended (and not recommended) audio interfaces: Survey of Working Audio Interfaces (VGGuitar Forums).

Internal Connections

Probably the trickiest part is how you actually wire the Neo in a guitar. The Neo Series Data sheet provides wiring diagrams (scroll down at the bottom). Here’s an example for Neo6:

example-wiring-neo6

For the internal connections (inside your guitar), Leo Pedersen offers a simple solution using Screwless Terminal Block to a DB25 Female Connector:

db25You might have to do a bit of routing to place that inside your guitar. Don’t forget to get a bunch of 4.7uF capacitors. You’ll need to insert them after each Neo output and before the DB25 connector. See diagram above.

For the other end, the one that connects to the Neo, you can either use a standard 2-mm spaced female header or simply solder the wires directly to the pins. The Neo6 uses a 10 pin male header (2-mm spaced). There are many good brands to choose from. We use gold-plated Molex connectors.

Crimp Terminal

Molex Crimp Terminal

Crimp Housings

Molex Crimp Housing

You can get these header terminals from electronics suppliers Digikey:

Power

Notice that two of the terminals connect to a battery or an external power supply. If you prefer batteries, you can use two AA batteries (Alkaline or rechargeable). You’ll need a battery holder such as this:

Battery-holder

All the other terminals connect to the DB25 Terminal Block. You’ll probably need an On-Off switch to turn off the battery when the pickup is not in use.

You may also choose to use external power instead coming from the DB25 connector. Should you prefer to use an external power source, be sure it is well regulated, supplying a very clean 1.8 V to 5.5 V D.C. supply. Either way, battery or external power, do not exceed the supply voltage maximum (5.5 V). Never use a 9V battery. The Neo1 is not protected against over-voltage. The Neos are protected against reverse voltage, but not against over-voltage.

Cabling

Once you got the internal connections done, all you need is a DB25 to DB25 and a DB25 to TRS cable to connect the guitar to your multi-channel audio interface:

db25-to-db25

db25-to-trs

That’s it. Feel free to ask any question, or if anyone has a helpful idea or alternative setup, that will be much appreciated! There are many ways to connect the Neos. Next time I’ll suggest other connectivity options. For now, I hope this helps. Stay tuned!

 

C Varnon says:

These pickups look great! I was pondering making some polyphonic pickups myself, but I think I like your design much better. Balanced outputs are such a good idea. I also really appreciate the flat response. I think guitar design is so often held back by the desire to emulate traditional or vintage sounds. Your designs are a refreshing step forward.

I am curious about using multiple neo pickups. Can a bridge/neck pair be connected in-phase and out-of-phase? I do a bit of work with electronics and microcontrollers, but differential amplifiers are not my strong area. For two pickups on a single string, pickup A and pickup B, would connecting VR A to VR B and O A to O B result in an in-phase summation? Would connecting VR A to O B and VR B to O A result in an out-of-phase summation?

I can also see where installing a mono-mode switch might be useful. Does connecting all VRs and all Os across several pickups in the same position result in a balanced mono signal? On the Neo 2 and Neo 6 the VRs are appear to already be summed.

Am I on the right track here?

Hi C Varnon,

Thank you for your interest! Multichannel pickups are best placed near the bridge for a couple of reasons. The most important reason is that there’s less string movement there. If you place the multichannel pickup in the neck position, you will have problems with string bending and crosstalk. Having said that, this recent post might interest you: http://www.cycfi.com/2014/07/virtual-pickup-placement-part-1/

BTW, to be clear, the output is pseudo-differential. That is why there’s a common. In terms of noise performance, it’s the same (http://www.maximintegrated.com/en/app-notes/index.mvp/id/1108). This configuration is especially suitable for ADCs.

I hope I answered your questions. We have a private forum where we discuss things like this with like minded folks like you. Send me a message: http://www.cycfi.com/contact/ if you want to join the discussions.

C Varnon says:

Thanks for the response and invitation. I see what you mean about the pickup placement. I didn’t consider that before. I also tried some of the comb filter pickup position emulation. It works pretty well. Very cool!

Alan says:

Ha, yes. Silly post … missing a noun. I think I understand the Neo1 wiring (though I have to learn enough about soldering to properly solder the little cutout contacts on the VRef module … but that’s a different issue. I meant to finish the sentence: “… PlanetWaves DB25 to TRS breakout cable.” How do I know what pins on the DB25 are for the shield or for the rings and tips of which plug. I just sent an email to PlanetWaves, but perhaps this information is well-known to non-newbies?

I’m not using the DB25 connector, but I believe this should help: http://www.fullcompass.com/product/449751.html

Double check just to be sure.

Alan says:

Perfect. Thank you!

Alan says:

I’ve already gotten the PlanetWaves DB25 to TRS breakout cable. I’m waiting on the Screwless Terminal Block. I can’t seem to find a pinout diagram for the. I need this, don’t I, to know what connections to make from the Neos to the terminal block? Should I be able to find it online somewhere?

“Pinout for the ___”. Did you mean Neo1? If so, please see the Neo Data Sheet. You can also find some wiring diagrams there and complete sets of design documents (CAD File, BOM, Eagle Schematics, Board, Layout).

luc BARREDA says:

Hi Mr de Guzman
VERY impressed by your products designs and thoughts, especially hex pickups and future hex sustainer.
I was wondering if you would have plans in the future for a bidirectional small modular interface to put inside the guitar to interface directly with a computer using raw UDP ethernet (like Gibson magic protocole ) with Power over Ethernet to power the guitar :

Something like this :
Neo 6 to 8 PU======> Top Q ADC => SoC board ===> Ultra low latency link using Ethernet => computer
Guitar controls ========>GPIO of the SoC board
+
Hex sustainer control <<== ADC <=== SoC Board <====Ethernet link <=== computer
(with output GPIO on the board if something needs to be controlled on the guitar ?)

All the intelligence being in the computer, the board just acting as an interface ?
That would allow max software upgradability, perhaps a very low latency, and to use industry standard wiring ethercon and cat5 cable.

Hi Luc, As a matter of fact, yes. We are working on an in-guitar audio interface that links to either USB or Ethernet. It’s interesting because the one you outlined is exactly what we are working on. Like minds!