Thinking on a Fluence with all options to an external box

[ryanc]

Hey all, new here but I've found some answers to some questions on here in the past and it seems like a great place for this thread-

So I'm building a not-a-strat that I want to make it extremely flexible for studio use only- using all the options available with a 3 pup fluence setup.

I have a Keith Merrow set that I'm going to use for neck and bridge, and still weighing my options for a middle.  The other 2 unusual twists here is I don't need (or want) any vol or tone pots, and I want to wire each pickup to a separate output.  No vol/tone because I tend to mess with them between takes and then they don't comp well, and separate outs because I can create cool stereo presets (mostly using TONEX) by panning the different pickups and using different amp setups for each.  No shortage of EQ/tone options in the DAW.

I know all of that is heresy to some, but rest assured that I have normal guitars too...

Anyway, I'm thinking instead of having a ridiculous amount of switches on the guitar- why not just run a multiconductor cable down to a desktop project box?  And, while I'm at it, why not just use a quality switching power supply in the box instead of a battery (I'm genuinely asking on both accounts, maybe this is a terrible idea!)?  I'm assuming all grounds should be shared(?), each switch option on the fluence has it's own ground pin/pad.

Adding it all up, I'm looking at about 20 conductors (depending on middle pup choice).  Obviously no 20 point connector will fit in a strat boat-tail in place of 1/4 jack, but I'm thinking maybe a 12" pigtail and an inline connector?  From there, maybe 8ft to the desktop box and and then short 1/4" cables to a DI.  Any recommendations on flexi ~20 conductor cable?

Any thoughts/input/diatribes appreciated!   

[cynical1]

I don't know anything about the Keith Murrow pickup set. They're active, right?  Seems like picking up a Fishman Fluence single coil pickup is the easy route for the "middle".

I like the idea of separate outputs. Especially if you're just recording.

As far as grounds go...  I know shared grounds are a bad idea in passive wiring schemes with separate outputs for each pickup.  Essentially, each pickup and output are it's own circuit.  Sharing of grounds is not recommended.  I have no idea on active guitar pickups.  Someone with a clue should be by soon to elaborate.

There has been discussions here regarding phantom power to onboard guitar components.  It's been 10+ years ago at least, so my immediate recall is cloudy, but it's not out of the realm of possibility.  I had a few onboard devices, but I believe I used DIN connector arrangement.  I don't recall how many conductors, but there are options.  I would recommend dropping the coin on the industrial type...you know, the ones that don't break when set the guitar on the floor reaching for a cigarette...

I understand dropping the tone knob, but I have to wonder about dropping the volume control.  If this is a studio instrument, I would think you would want to preserve as many tonal options as possible.  You can always toss in a blower switch...



Switches...sure, love 'em...

Happy Trails -

Cynical1

[ryanc]

Yeah, the fluence pickups are all active, they also have different "voices" where with a switch you get a different resonance peak/response.  Also, the Merrow have a single coil mode and another switch option to chose which coil is used.  I want to bring all those options, per pickup, out to a desktop control box.

And yeah quality connectors, looking at some aviation panel mount types on ebay.

On the vol knob- yeah, I get that, I have a preamp that has linkable channels, so I can also just adjust volume there as well (to all 3 pups at once).  It's much more repeatable because it adjusts in exact 1dB increments (it's a digidesign PRE).  I think that setup will work better for me because I tend to instinctually adjust the vol on the guitar and then waste time trying to get back to where it was...with the PRE as vol control, I can set it to 25dB and get back to that exactly.

But that's good to know on the grounds, I guess the whole ground situation is where I have the most confusion- especially if a power supply is used.

All the pickup switch points have their own ground pin- so it would be possible to have discreet "switch ground", "signal ground" and "power ground".   I'm just not sure where they would be separately grounded too.

Here you can see all the solder and pin outs on the pickups. 

[cynical1]

This was as close as I could find on Fishman's website for 1 pickup per output wiring:

Remove the pots and it looks like everything goes straight to the switch, isolated star ground and output jack. 3 jacks, 3 switches...and 3 nine volt power sources required.

sumgai and I talked about this on an idea I had when I still had hair...It involved a sustainer and MIDI out, along with passive pickups. The original thread was Bypassing Fernandes Sustainer It wanders a lot, but it follows a similar theme.  The power supply was external with a pretty good size transformer, which I still have in a box...then a simple circuit out for each required power tap. For the life of me I don't remember how it went together, but it's a similar concept to a pedal board power box. You just need to calc the power requirements per device.

Yeah, this is doable.

HTC1

[sumgai]

ryanc,


Hi, and to The NutzHouse!


Phantom power is not that hard to do, it just takes some careful thought, with a nod towards safety as well. Regardless of how you implement it, that'll take two conductors.  From Fishman's website, we see that each Fluence pup needs three conductors. That adds another nine conductors, bringing you up to 11 total. You don't need a separate ground anywhere, so you're good to go at this point.

Now for the pieced'resistance - visit here to inquire of gumbo if he'd kindly send you a Synth-Linx outfit for your rig. You can then use a Roland (or other maker's) 13-pin cable to transfer your signals to a breakout box, or even directly into the sound card on your 'puter. But the breakout box is the better idea if for no other reason than you can put your phantom power supply in there as well.

Just be aware that most 13-pin cables have only 12 conductors - pin 9 was unused in the original spec (by Roland), so you're still good to go, but there are differences in both quality and pricing, that 'extra' wire being one of them.  And don't stint on backup cables!  The cables themselves aren't shoddy, but some outlier manufacturers don't always install quality connectors at the ends.  Just sayin'.....

HTH



sumgai

p.s. gumbo is also a member here, but he checks in with us only a few times a month, whereas over at VGuitarForums, he's there almost daily.

p.p.s.  Full Disclosure - I have worked with gumbo on this project, but I receive no money for anything he sells.

[sumgai]

I see now that I glossed over something....

You need only one power supply for the whole rig, not three separate ones. The 'creation' of the 9-18VDC supply for the pups will occur at a device which will be isolated from the mains ground (usually a transformer, but regardless of how it's done, that isolation will occur). That mains ground is also a reference point for your pickup grounding, and presumably there might be 'ground loops'.  Thankfully, no - ground loops occur only when signal grounds are improperly commingled, not power grounds.

Keep the three signal (pickup) grounds separate, because when they enter the breakout box, and then go to three separate computers, amps or whatever - those devices are all powered from a common mains ground. Only at that common point should the signal grounds be combined. That's how one avoids ground loops when dealing with multiple signal sources.

HTH




sumgai

[kitwn]

What an interesting project! I've nothing to add on the connector front other than to add a warning about using switch mode power supplies, some of which can produce a lot of noise.

Kit

[ryanc]

Thanks everyone!

So sumgai. I think I actually need more than 12 conductors because I want to be able to have all the options available per pickup.  The fishman diagrams are always wiring them to where one switch changes both pups to v2 or single coil mode etc.  I want to have probably ~15 switches so for instance the neck pickup only could be switched to SC and V2.  

There is-

DC+ and Ground (2)

2x V2, SC, HFT, Neck, Bridge (10) + 2 outputs

So even without a middle pickup I'm at 14.  I'm leaning towards a fluence modern alinico for the middle

Assuming another middle with as many options that would bring me to 20 conductors.

kitwn I have a large container full of orphaned PSUs, most of them came from audio gear but they could still be too noisy for sure.  I figure I'll try those and see.  Do you think a power supply made for a stompbox would be quiet enough?


One probably dumb question here, the cable should be shielded right (foil or braid?).  And then the ground wired to the shield?  I can't imagine pickups pulling much current, but maybe a shield on the cable isn't necessary.

And another one- with staring all the grounds down to the power-supply, it seems like it would be better to NOT tie the ground to the bridge too?  

[sumgai]

ryan,


You know, I'm getting stupid in my old age, because I fail to see the need for separate ground contacts per voicing. We need to see how everything is constructed inside of that 'black box', and until then, I can't give you a definitive answer. (Nor should anyone else here attempt to do so, unless someone shows up with a Fluence in his/her hand.)

Do you happen to have a Fluence on hand at this moment? If so, can you use a multimeter to do a resistance check for us, please? That would be a good start, since we're lacking a factory-authorized drawing of the internals.






sumgai

[JohnH]

Reading about the design intent described here, my instinct would be to keep the three Strat knob positions for a rotary switch, one per pickup. Then just take three conductors plus ground back to the main controller, or maybe 4 for remote power to the guitar. I'd feel that'd offer a simpler more reliable connection to the guitar from your main box.

[kitwn]

Mar 25, 2023 12:31:52 GMT -5 JohnH said:

Reading about the design intent described here, my instinct would be to keep the three Strat knob positions for a rotary switch, one per pickup. Then just take three conductors plus ground back to the main controller, or maybe 4 for remote power to the guitar. I'd feel that'd offer a simpler more reliable connection to the guitar from your main box.

A simple and very elegant solution which sounds like a winner to me.

Re power supplies: Any supply which came out of a piece of audio gear aught to be OK, but obviously needs testing to make sure.

Kit

[Yogi B]

Mar 25, 2023 12:10:37 GMT -5 sumgai said:

Do you happen to have a Fluence on hand at this moment? If so, can you use a multimeter to do a resistance check for us, please? That would be a good start, since we're lacking a factory-authorized drawing of the internals.

I don't know if that'd be super helpful as I suspect anything useful we could learn about the internals is hidden from a multimeter by way of the active circuitry or at least a capacitor. Fishman's "Connection Points & Functions" document may prove somewhat useful.

That mentions the Voice-2 selection being performed via an electrically controlled switch, and though the text isn't as explicit with the Single-coil/Voice-3 pin I'd hazard a guess that it's similar since it does somehow override the choice between voices 1 & 2. That being said, I'd also guess the coil selection is done via grounding the relevant input of a summing amplifier (at least that's my first thought when confronted with what is effectively a SPDT (in solder pad jumper form) for coil selection paired with only a connection to ground to enact that selection), and that could certainly done without any additional active components in the switching path. So perhaps readings from the ("Neck"/"Bridge") single coil mode selection pads could give some insight.

It is specified that the HFT (High Frequency Tilt) pad has signal on it, but being what it is (some form of fixed LPF) and that it's enabled via a connection to ground, it's highly likely there'll be a capacitor in series with it.

---

Engaging in some blue-sky thinking and considering the absolute minimum of conductors you could conceivably get away with, that number is three (or more likely four): power, ground, and a single serial data line (but realistically this would be balanced, hence four). This assumes everything is digitized, thus the guitar would require onboard digital-switching/relays and a three channel ADC to handle the output of each pickup. At that point there would also be the potential to make the switching software controlled and/or MIDI compatible. A more realizable middle ground might be to retain the audio as analogue and only digitize the switching interface.