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DIY Stompboxes => Building your own stompbox => Topic started by: anotherjim on January 12, 2018, 05:25:22 AM

Title: 1/4" jack socket intended for battery power switching (Not a TRS)?
Post by: anotherjim on January 12, 2018, 05:25:22 AM
I'm building a kit bass at the moment (great fun BTW) and came across something I haven't seen before  :icon_eek:
The jack socket supplied is a round barrel type (like the ones in cable extension sockets but with longer threaded barrel).

The socket has 3 terminals so I assumed it was TRS. The bass isn't active, but I assumed they supplied these in case it is for switching the battery negative just like you do with stompbox input jacks.

Anyway, I continuity test the terminals with a TRS plug inserted.
What I assumed was the ring terminal made no connection to the plug ring.
If I withdrew the plug a few mm, the ring contact made.
At first I though "yeh, typical cheap crap". Because I was hoping to use it as TRS for a stereo output option. Damn.
Actually, it's a decent metal (non-ferrous ) construction.

Could it be purpose made with a second Sleeve contact for battery switching?
Maybe I haven't noticed any before because I wasn't looking, but does anyone know of source for similar, preferably panel mount ones?
And are there any TRS with an extra sleeve contact?
I'd search, if I knew what to search for ;)
Title: Re: 1/4" jack socket intended for battery power switching (Not a TRS)?
Post by: YellowBoy on January 12, 2018, 06:21:27 AM
Are you sure it's not just a case of "typical cheap crap" as you say?

Does it look like this? Usually seen in some telecaster/LP copies...

(https://s18.postimg.org/4u53uhrhx/F7051484-01.jpg) (https://postimg.org/image/4u53uhrhx/)

The only switched jack sockets I've ever come across are the usual suspects...I reckon because the barrels are just too narrow to accommodate the mechanical switching bits and bobs.
Title: Re: 1/4" jack socket intended for battery power switching (Not a TRS)?
Post by: antonis on January 12, 2018, 07:35:07 AM
Jim, maybe you use them with 6mm plug..

(silly, of course, but sometimes...)  :icon_redface:
Title: Re: 1/4" jack socket intended for battery power switching (Not a TRS)?
Post by: diffeq on January 12, 2018, 08:35:58 AM
I've seen a related trick - turning the effect on when plug is insrted:
http://web.archive.org/web/20071017192756/http://gaussmarkov.net:80/wordpress/circuits/bipolar-9v-power-supply/

There are plenty TRS sockets with "multiple" pins. Just add "four pins/six pins" to the query. Some off aliexpress:
https://aliexpress.com/item/10pcs-Vertical-Thread-Lock-Panel-Mount-0-250-6-35mm-Mono-phone-Jack-female-Headphone-Connector/32768102151.html?priceBeautifyAB=0

https://ru.aliexpress.com/item/5-pcs-Thread-lock-panel-mount-1-4-6-35mm-stereo-phone-Jack-socket-Headphone-Connector/32756913909.html?priceBeautifyAB=0
Title: Re: 1/4" jack socket intended for battery power switching (Not a TRS)?
Post by: anotherjim on January 12, 2018, 09:16:41 AM
(https://s18.postimg.org/4u53uhrhx/F7051484-01.jpg)
Yes, similar, but sleeve/case terminal is without the cable clamp.

& thinking about it - the usual chassis/pcb types don't have room for an extra sleeve contact.

I should make it clear that I was wondering about sockets with an addition sleeve contact which will intentionally miss the ring portion of a TRS jack. Most of them rely on sleeve contact via the aperture only - there is no actual contact "finger" used. I'm thinking of a contact similar to ring & tip in operation and similarly isolated with no plug inserted. If a TRS plug should be inserted, the ring conductor does not get connected unless the socket also has a ring contact in the usual place behind the tip.

Consider the effect of plugging a balanced TRS into an output with a 9v battery negative on the ring  :o

...Ah, found something...
(http://www.axetec.co.uk/axetec_media/sckt06_connections_550b.gif)
This is what I have!
...and...
(http://www.axetec.co.uk/axetec_media/sckt07_connections_550b_2.gif)
..This would work for TRS "stereo" AND switch a battery negative. It calls the Ring contact "Centre".
& I think I guessed right -  there is an additional sleeve contact and it should miss the ring.