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Author Topic: Shallow Stereo Jack with Ground Switch?  (Read 1174 times)

Offline Noodler

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Shallow Stereo Jack with Ground Switch?
« on: March 07, 2017, 05:27:29 PM »
Some of you may recall that I retrofitted a Fly Mojo SC (in Natural Mahogany finish) with gold hardware and the Fishman Powerbridge piezo system.  One of the problems, that I never solved, was that there wasn't enough room to install either a 9-pin stereo jack (that comes with the Powerchip) or a 4 lug "ground-switch" stereo jack (like those used in the new Flys).  Because my design uses a normal 3 lug stereo jack, any battery left installed in the system will die a quick death if I do not remove it (since the circuit is never disconnected upon removal of the guitar cable plug).

Is anyone aware of a "shallow" 4 lug stereo jack with the integrated ground switch?  If not, anyone have any ideas on how to possibly modify an existing 3 lug stereo jack or wire the system in a way that will not kill the battery?

Without any new ideas from fellow forumites, I'm considering either going with a push-pull pot on the mag volume control to "switch in" the battery or completely removing the Powerchip preamp and going passive for the piezo (since I do own the outboard Fishman Powerblend pedal that I can run the piezo into).  Going passive for the piezo has its pros and cons, but I think I would prefer to stay with having an active preamp (the Powerchip) in the guitar.

Re: Shallow Stereo Jack with Ground Switch?

Offline Noodler

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #1 on: March 07, 2017, 05:50:06 PM »
So I found what I was looking for on the GraphTech site: http://www.graphtech.com/products/brands/ghost/product-detail/pd-0103-01-ghost-stereo-switch-jack?id=77496e6b-7adf-4c2e-b261-e395656deb1d

But the darn thing is listed for $21.55.  That's ridiculous for a stereo jack, so I think I'm going to go search on mouser.com now that I know that this shallow version of the jack does exist.


Re: Shallow Stereo Jack with Ground Switch?

Offline Noodler

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #2 on: March 07, 2017, 06:12:16 PM »
Anyone else who may be interested in purchasing the GraphTech jack for much cheaper from mouser ($10.54): http://www.mouser.com/ProductDetail/Switchcraft/14B/?qs=sGAEpiMZZMtUpMOmSPzkH%2fi%2f1KDxchf7

Re: Shallow Stereo Jack with Ground Switch?

Offline sybersitizen

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #3 on: March 07, 2017, 06:37:31 PM »
Hmm... so, could that jack replace the original "hand-made" jack in pre-refined Flys if the original ever failed?
'01 Fly Deluxe|'69 SG Standard|'69 EB-3|Pignose Strat|Savannah SGO-16CE|Fishman Aura Spectrum|Roland Amplifiers

Re: Shallow Stereo Jack with Ground Switch?

Offline TinMachine

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #4 on: March 08, 2017, 12:03:00 AM »
Wiguitar probably has some listed.

Re: Shallow Stereo Jack with Ground Switch?

Offline Noodler

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #5 on: March 08, 2017, 11:55:20 AM »
Wiguitar probably has some listed.
He only has the 9-pin jacks listed (incorrectly described as 8 pin).  It would be great to get my hands on a couple of the "refined" ground-switched 4 lug jacks (although they wouldn't work for this particular project, too long).

I'm pouring over the GraphTech wiring diagrams trying to figure out how to make this switching jack work.  It defaults to "closed" when a plug is NOT inserted.  That seems to be opposite of what you would need to keep the battery from draining, but clearly GraphTech makes this work for their installations.  So I'm missing something in my understanding...

Re: Shallow Stereo Jack with Ground Switch?

Offline TinMachine

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #6 on: March 08, 2017, 04:24:12 PM »
I know the Fishman ones can be ground down, would you be able to grind it enough to fit?

Re: Shallow Stereo Jack with Ground Switch?

Offline billy

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #7 on: March 09, 2017, 07:53:22 PM »

I'm pouring over the GraphTech wiring diagrams trying to figure out how to make this switching jack work.  It defaults to "closed" when a plug is NOT inserted.  That seems to be opposite of what you would need to keep the battery from draining, but clearly GraphTech makes this work for their installations.  So I'm missing something in my understanding...

Not sure how the ghost switching works but I had the same thought when I looked at the jack you linked to. I believe that jack is tip shunt unless there's some clever fet switching or similar via signal. So not only always closed but also signal not power.   Afik You need ground or barrel shunt. I don't remember why the other jack won't fit?  More info about that and I can probably help find something.  The jack you linked shouldn't cost more than $3-4 at most.
Billy

[always the beautiful answer who asks a more beautiful question.  e. e. cummings]

Re: Shallow Stereo Jack with Ground Switch?

Offline Noodler

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #8 on: March 10, 2017, 12:50:17 AM »
I know that most of the "old timers" may not recall (and definitely not any of the forum newbies), but I added a Fishman Powerbridge to my Single Cut since the original version of the SC Flys did not include the piezo or Powerchip.  The cavity on the SC is small (typical LP guitar type cavity) with very limited room for a non-standard jack of any length longer than your typical mono chassis-mount jack.

So the 9-pin jack won't fit and the longer 4 lug switched ground jack used in the refined Flys won't fit.  Neither jack could be modified to fit either.  Also, the Fishman Switchjack (end pin style) wouldn't fit either.

Anyhow - back to the Switchcraft 14B jack, unfortunately the GraphTech wiring diagrams don't really help much because they all assume you're using their preamp board (Acousti-phonic), so they don't really show how the shallow 4-lug stereo jack works since some of the circuit is "hidden" on the preamp board.  I'm no electronics genius so I need help figuring out how to make the Switchcraft 14B jack work to cut off the battery power when there's no plug in the jack.

Re: Shallow Stereo Jack with Ground Switch?

Offline Big Swifty

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #9 on: March 10, 2017, 01:54:46 AM »
I'm a little rushed right now, but generally switched jacks.... The switches are normally closed and break when the plug is inserted, this is to do with audio routing, as in patch bays, so you can have a signal normally going trough the switch, insert the plug and it breaks the contact and sends (or receives) from whatever is plugged into it.

This is different to power on/off.

Check how standard guitar pedal plugs are wired for battery on off, and go from there, you aren't necessarily using the "switch" itself, use the actual barrel of the plug to make contact between one legs of switches

Bugger, bad explaining.. but hope that helps a little, gotta scoot, be back next week if someone hasn't figured it out already.

Can be done though.

I think the only thing going on on the Powerchip is "active sensing" mono/stereo.

Like i said , in a rush so take all this with a grain of salt.

Ciao

B.S.

94 Fly Deluxe
2010 DF 524
The system can't get you in your dreams.

Re: Shallow Stereo Jack with Ground Switch?

Offline billy

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #10 on: March 10, 2017, 01:16:50 PM »
those are actually pretty good descriptions swifty, per usual (I get lazy typing on my phone).  Also didn't realize it was powerchip, saw the graphtech link and assumed it was the ghost, though not much difference in this regard.

So what happens in a stomp box is you have a TRS jack with the sleeve connection, and also a contact for the ring, much like the one that goes to tip.  But, since most guitar cords are the tip/sleeve variety (not TRS), you can "make" a ground connection between the ring and sleeve contacts using the longer sleeve portion of the plug to short them together.  So power is on when plugged in, and the connection is broken when the plug is removed.  (Earlier, I called the sleeve the barrel, sorry for any confusion)  Assuming you don't know this already, but if so, hopefully it still helps others.

In this case its a little trickier, because you're already using TRS jacks and TRS plugs, but you may still be in luck. 

http://www.neutrik.us/zoolu-website/media/download/2804/Jack+Circuits

It looks like they make such a thing, if you check the diagram for something called "sleeve make" 3x switching, which includes some extra contacts (6 position) for switching each of the 3 main contacts.  NMJ6HCD2-SM = $1.27 at mouser. 

However, it looks like the threaded portion is plastic, which might kill it for you.  At the least this info should help find something by another supplier.


Billy

[always the beautiful answer who asks a more beautiful question.  e. e. cummings]

Re: Shallow Stereo Jack with Ground Switch?

Offline Big Swifty

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #11 on: March 14, 2017, 02:57:07 AM »
Hey Noodler, u got it figured out yet?
94 Fly Deluxe
2010 DF 524
The system can't get you in your dreams.

Re: Shallow Stereo Jack with Ground Switch?

Offline Noodler

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #12 on: March 15, 2017, 07:36:20 PM »
Unfortunately I do not have it figured out yet.  Although the advice to look into how pedals with true-bypass use these seemed to be on target, none of the info I found was using these jacks in TRS stereo mode.  That's really where the challenge lies; how to use a stereo switching jack with a stereo TRS plug.  The "trick" of having the sleeve of the plug complete the circuit doesn't work in this scenario.

Also, GraphTech never replied to my email asking them about it either. 

I'm a few steps closer to just going passive and ripping out the Powerchip.  It stinks to lose the use of the piezo without having to use the Fishman Powerblend pedal, but there are worse things in life... ;)

Re: Shallow Stereo Jack with Ground Switch?

Offline Big Swifty

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #13 on: March 15, 2017, 07:46:11 PM »
Yeah right, i think the stereo thing is going to be the problem, 9 lug jacks get around it somehow..have to do some investigative head scratching.

I've had the naughty stick waved at me by the taxman so gotta put my time into keeping them at bay this week..when i get the chance I'll have a look in my DF 524, see what goes on in there. Also got a spare powerchip in a box someplace, must've come with wiring diagram etc.

Hang for another week or so if you can..no guarantees though, but you never know!

B.S.
94 Fly Deluxe
2010 DF 524
The system can't get you in your dreams.

Re: Shallow Stereo Jack with Ground Switch?

Offline billy

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Re: Shallow Stereo Jack with Ground Switch?
« Reply #14 on: March 15, 2017, 08:24:44 PM »
The ground sleeve trick can still work, you'd need a TRS plug, and a TRRS jack.  They make these in 1/8" sizes for iphones and what not, but not described as such in 1/4".

However, I did come across this, which I think will work if I understand your size constraint:

http://www.stewmac.com/Pickups_and_Electronics/Components_and_Parts/Jacks/9-lug_Stereo_Jack.html?utm_source=google&utm_medium=shopping&utm_campaign=2017-03-gp&gclid=CKzi9s3t2dICFZdKDQodZ2QGAg
Billy

[always the beautiful answer who asks a more beautiful question.  e. e. cummings]