Help with jack connection (pictures)

drissa · May 13, 2008, 08:06:52 PM

Sorry to be dumb - can anyone offer advice for fitting this jack output? I understand that I need to connect the 'tip' point of the socket (which I assumed was one of the points nearest the output end - the one actually connecting to the tip of the lead) to the + lead going to the speaker. I tried holding a lead in place, but can't get a signal to the lead. I'm not sure which is the +/- in this toy - I'm trying both, at the point they connect to the speaker. The bottom lead in the picture is the one going to the circuit board.

Oh dear, I'm rather stuck.

Any advice appreciated. This thing sounds great, but I need to plumb it in...

Oceanus - XD515 · May 13, 2008, 09:08:07 PM

Hi,
That type of connector has 4 connections, 2 either side. They are switched connections. If you insert a jack plug you will see that 2 of the connectors pass over the jack and the other 2 connect to nothing once the plug is inserted. you need to solder wires to the 2 connections on the side that passes over the jack plug. The connection at the back of the connector is the positive ( tip ) connection and the other one nearest the nut is the ground.

If you connect an amp directly across the speaker it should work, then remove the wires from the speaker and connect them to the jack socket.

However one very important thing is that you must block any DC voltage, some toys can have a 5v DC ( or more! )level on the audio, which will not do your amplifier any good, so insert a polarised capacitor ( 10uF ) in series with the tip signal of the jack, with the negative side of the capacitor going to the tip and the positive side going to the speaker wire.

Cheers

Paul

drissa · May 13, 2008, 09:44:36 PM

Hmmmm, I'm still not 100% sure, but thanks for the info. Is this connector designed for stereo use? Is that why there are two sets of connections?

So I cut the wire coming from the circuit to the speaker, and reconnect to the end point (eg. the right hand point in the photo - the one with some solder on)... oh dear, I'm lost. I think I'll need to look for some diagrams and then come back.

I guess I couldn't expect to do this without any electrical experience.

iqoruvuc · May 14, 2008, 10:49:14 AM

Hi - no the socket is mono. Each socket has has to have at least two connections. Imagine a simple circuit - one wire takes power from the battery to a light bulb (+) the other takes it back from the bulb to the battery (-) - there always has to be a circuit. It is the same for audio signals the tip or (+) takes power to the speaker/headphone/line in and the ground or (-) takes it back. First thing to do is mark the wire that connects to the (+) of the speaker. Then remove your speaker. Check the impedence on your speaker (normally between 4-32 ohms and in place of the speaker solder a resistor to the closet value i.e. 16 Ohms solder a 15 Ohm resistor). Then solder another wire to the side of the resistor that connects to the (+) wire you marked earlier. To this wire solder the (+) side of 10uf capacitor and then wire the other side to the part of the connector that goes to the tip (with the sockets you are using the connection furthest away from the thread/nut) Without having the socket I don't know whether you solder to the left or the right side of the jack so insert a jack plug and see which side makes connection with the jack (part of the metal connector will lift) and it is this siide you use. Then solder another wire to the same side of the socket but to the ground terminal (near the nut thread) and solder this wire to the other side of the resistor that you replaced the speaker with....it should work then though the signal may be too loud. Best trying with test leads first. Hopefully that makes some kind of sense

Can someone tell me why speaker cable on hifi amps are not normally grounded?

?

drissa · May 14, 2008, 06:34:24 PM

Thanks. This is pretty much what I was thinking, although I don't have any resistors or capacitors yet. I read that I could use a pot instead? I guess a DI box would achieve the same result, in terms of matching levels? I have various options for attenuating the level before tracking, so I should be OK.

Can I just confirm something....? The ground from the jack socket returns to the resistor, not back to the toy itself? In other words, the - connection from the speaker is no longer used? If I used a pot, it would return to the other side of this? I'm less clear about this part of the signal, but I'll get my head around it eventually.

Thanks for your patience everyone!

iqoruvuc · May 15, 2008, 11:38:18 AM

It returns to the speaker ground which should also be connected to the resistor. If you remove your speaker you will ahve a (+) wire and a (-) wire. The (=) will need to be soldered to the resistor and also the wire that will go to the (+) part of the jack socket (via the capacitor). The (-) wire from the speaker will connect to the other side of the resistor and also to the wire that meets the ground on the jack.

drissa · May 18, 2008, 11:53:01 AM

Thanks. That makes sense.

drissa · May 20, 2008, 07:40:29 PM

Sorry folks. I really am stuck on this and I'm so keen to put the bloody things back together and start using them.

I've disconnected both wires from the speaker and attached them to a jack socket (not the one pictures above). I can see the tip and ground points on the socket and I've tried every combination to complete the circuit (just in case I'm mixing up the +/- from the toy). Not a sausage. When I simply touch the wires back on the speaker, the signal is there.

Is the capacitor essential? Any ideas about where I'm going wrong?

To clarify, this is what I'm trying:

+ from circuit board > tip of jack socket
ground of jack socket > - back to toy

Lead is plugged in and I'm watching input levels for a signal. I'm getting signal from the tip of the lead, but not actually from the toy.

Sorry for being slow...

Gordonjcp · May 20, 2008, 09:22:02 PM

Try wiring the jack across the speaker, so you get noise from both the speaker and the amp you've plugged in. If that works, replace the speaker with a resistor, perhaps between 470 ohms and 1k.

drissa · May 28, 2008, 11:39:55 PM

Thanks folks. I ordered some resistors and a bundle of test leads, which have made things so much easier. Everything is working fine, although I haven't yet managed to hook things up so that I disconnect the speaker when the jack is inserted. I have the right socket, so will start figuring it out.

boneless · May 29, 2008, 03:41:23 PM

Hello. I found looking at the switch jack whilst I put a lead into it helped. You can see the action of inserting the plug breaking the circuit. Simple and clever!

Thanks to all for all this info re:line outs.

I too have been struggling a bit - with getting decent line out sound on my projects when speakers are disabled with toggle swirches - hopefully the resistor and capacitor setup will sort it - I've just been wiring em up without any components at all!!

Also a question if I may...

When Oceanus said toys can emit dc charge on teh audio what does that mean? And why does the polarised capacitor in series with the +ve line out work?

I thought capacitors stored and released charge so won't that make the sound out fragment?

(Apologies in advance for showing my lack of electronic background newbie ignorance !)