Help! Behringer Jack problem

[Xelent]

Hi there,

I'm recasing a Behringer Digital Delay pedal (one of the super cheap ones) into a new case.

It has audio jacks made by 'Chunsheng', and I need to replace these jacks with switchcraft jacks, in order to mount them into the box. 

I am doing this by soldering leads onto the original jack's terminals, and 'hijacking' the signal.

I have sucessfully done this for the output jack(s), but I am having trouble with the input.

The input jack appears to be a different model, and is used for jack switching.

I can get the jack switching effect by connecting two of the jacks terminals together (the pair at the back), but I cannot get any audio signal.

This is the Datasheet for the jack : http://www.chunsheng.com/img/spec/PJ-617%20A.pdf

I was wondering, can someone please help me figure out which terminals from the original Chunsheng jack need to be connected to the ring/tip/sleeve on the switchcraft jack I have?

I'd greatly appreciate it.

Riley

[anchovie]

That datasheet has the schematic/pinouts in the bottom right-hand corner. If by "the pair at the back" you mean pins 2 & 3, you'll see there are two variants of the jack that use both of those pins and in both cases pin 2 is tip and pin 3 is sleeve. Pin 1 is ring in all cases.

[Xelent]

Thanks very much for your help!

Unfortunately, for some reason I am still struggling with this.

I feel like I've tried every possible combo.

This is what I know:

Connecting pin 3 to pins 1 OR 2 will turn the device on (that's the jack switch).

This makes no sense to me (why two options?).

Also, I still cannot seem to get any audio signal, which I believe is supposed to be pin 4 to sleeve?

This is the very last step of this recasing, I just want this thing done!!!

Any ideas?

Thanks,

Riley

[Xelent]

I tried the configuration you mentioned, BTW.

The circuit turns on when the plug is inserted, but there is no audio signal.

Help!

[anchovie]

With the plug inserted, I'd expect to see that:

Pin 1 is ground
Pin 2 is the audio signal (jack tip)
Pin 3 completes the battery circuit (sleeve)
Pin 4 is open circuit (this would normally be used to ground the input when there is no cable plugged in)

[Xelent]

Hmm.

Well, I tried the configuration you mentioned, just a minute ago.

I am a bit confused as to where to connect the ring?

And I'm not sure the audio signal is carried by pin 2. Connecting pins two and three completes the battery circuit.
I cannot for the life of me understand how this little problem could be so hard to fix!

Basically my questions is, what are the four pins on the chunsheng jack? Why four?

I feel stupid 

[anchovie]

Ring is pin 1 - this goes to ground.

My configuration is based on what is on the datasheet, I haven't made anything up! 

Pin 2 has to be audio - if you look at the variant PJ-617-01 on the datasheet, this is the mono version and doesn't even feature pin 3.

Like I said, pin 4 is a switch that would be used to ground the input when there is no plug inserted. If there is a plug, it does nothing as it is open circuit. This type of switch is more commonly used on amp inputs rather than pedals. If the new socket that you are trying to connect does not have a switch contact then you do not need to worry about it at all.

Can you post a picture and/or datasheet of the Switchcraft jack that you are using, and maybe even indicate on the picture which terminal you think relates to which pin on the Chunsheng?

[puretube]

2=TIP (signal)
3=RING (connects battery to ground, when plug is inserted)
1=SLEEVE (ground)

4= switched contact, connects to tip (2) when NO plug is inserted,
    but opens up, when plug IS inserted;

i.e.: you wire pin 4 to circuit ground on the PCB,
so that the input of the effect-circuit is shorted to ground when nothing is hooked
up into the input jack
in order to avoid hum/oscillation problems.

above concerns an FX input-jack.
 

[anchovie]

3=RING (connects battery to ground, when plug is inserted)
1=SLEEVE (ground)

Oh gosh, as soon as I saw that typed out, I knew I'd got those two muddled up!

Sorry Xelent. 

[Xelent]

No problem at all, I thank you both greatly for your help!

I won't have a chance to test this until a little later, but I think you guys have got it figured out.

I'll tell you how it goes, and when it's all finished, I'll post pics of the finished product!

Thanks again,

Xelent

[Xelent]

Okay.

I tried it, but still no audio.

I still feel like there is something obvious I am missing.

Here is a wiring diagram I have drawn up, explaining wich of the chunsheng jack pins are connected to which of the switchcraft jack pins.

http://xelentdesign.com/delay-ring-tip-sleeve-jack-diagram.png

And here is the data sheet for the jack I am using, bought last minute from a radioshack up the street.

http://www.radioshack.com/product/index.jsp?productId=2062453

What the F%&k am I doing wrong?

[davent]

The way i understand it is you have the original jack still mounted on the board and have run the wires from that jack's terminals to your new jack. If that's the case, (if it's not the case then just ignore me) when you plug into your new jack the old jack on the board  would still have the input connected to ground. Your signal gets to the old jack and stops, for the original jack to pass on the input signal the internal contact has to be broken  between 4 and 2.

dave

[Xelent]

Of course!

That's it!

I walked right over, connected a dummy cable into the original jack, and the actual audio input cable into my jack, and it worked.

Two things:

There is a considerable buzz on the line, what would be causing that?

And I still need to then figure out a way to hack it to work with my jack, then.

[davent]

Hi Riley,
Don't know about the buzz but you could just pop something like a piece of 1/4" dowel into the old jack and leave it there to keep the contacts seperated. Maybe the fact that the free end of the patch cord you plugged in was floating is causing the buzz.

dave