Easy to make "patch cord" for headphone use......

[Digger]

The reason that some headphones don't work on the CTX 3030 is because the jack in the headphone module requires the Sleeve lead to signal the detector to shut off the internal speaker. If you look at a stereo jack, you'll see three individual "contact points". Tip, Ring and Sleeve.

[attachment 236577 tipringsleeve.jpg]



By design, a MONO jack physically combines the ring and sleeve leads, providing only two contact points.
[attachment 236576 tipringmono.jpg]



This "connection" allow the detectors electronics to detect the presence of the plug and disconnect the internal speaker.

One of the suggested "solutions" on Minelab's website is to purchase the 1/4-inch mono to stereo adaptor at a cost of under $3.00. However, some have expressed a concern with having the length of two plugs sticking out of the back of their detector. I agree that it does lend itself to being bumped. Especially if the headphones you are using also have a straight plug. My objective was to build a short "patch cord", allowing flexibility at the jack assemblies and not add to the lenth of the plug sticking out of the back of the headphone module. By using the patch cord and not altering the wiring within a given set of headphones, I can use those headphones on my other detectors. Plus, if I want to use a set of Stereo headphones, such as the Koss UR30's that come with the CTX 3030, I simply unplug the patch cord and directly connect those headphones.

To accomplish this, I connected the Ring and Sleeve lead by taking advantage of the design characteristics of a MONO plug. As I said in the previous paragraph, the MONO plug combines the Ring and Sleeve leads, thus signalling the detector to shut off the internal speaker. Then it simply became a matter of connecting the two audio leads of the Mono Plug to the Tip and Ring of a stereo jack. Then when you plug the new MONO plug into the detector, the speaker will shut off. The audio is now being provided to your headphones via the new Stereo jack. It takes about 5 minutes to build it, with only four solder connections and a short piece of two conductor cable. For those that don't want to make four solder connections, you can purchase a Mono plug with a short "two wire" cable already attached, as I have done with mine. Then all you have to do is connect (solder) the two wires to the terminals of a Stereo jack, secure the jacket of the cable, install the jack cover and you're good to go.

[attachment 236569 2solderconnectionstipandring.JPG] [attachment 236575 finishedadapter.JPG]

[attachment 236571 straightplugheadphones.JPG] [attachment 236574 90degreeplugheadphones.JPG]

 

[earthmansurfer]

Digger, I have to say, that is a really nice solution.

I wonder if there already exists a stereo to mono adapter with the small extension between them?

Thanks a lot for that.
Albert

 

[Digger]

I wonder if there already exists a stereo to mono adapter with the small extension between them?

Could be? But make sure you get the 1/4-inch mono to stereo adaptor, not the stereo to mono adapter. With only two wires running between the new plug and new jack, you have to send the disconnect signal from the headphone module jack. HH Randy

 

[BarnacleBill]

I designed one of these for a buddy to correct the headphone issue for certain brands and tested it with a set of Nugget Busters.

Below you see the finished item by itself and plugged into an X-terra to give you the idea of how it "lays", that is the flexibility.

[attachment 236903 FinTotal.jpg]

Whenever I do a design I always start off with a fixed set of goals I want to achieve. In this instance I wanted a very flexible yet rugged design that would put the least amount of stress on the CTX jack yet be reliable. I specified a "wet noodle" type of cable that is very flexible and yet has a double jacket for longevity.

[attachment 236904 DblJacket.jpg]

I also wanted a copper outer shield as this is what's needed to reject low frequency incursion as opposed to a foil shield. In this instance the copper is OFC(Oxygen Free Copper) which is a very high quality wire. The polyethylene insulator is a very good dielectric and I also wanted a relatively thick center conductor which in this case is AWG # 20 for strength. I really dislike the hair thin AWG # 26 and up wires as they break by just looking at them.

[attachment 236905 CenterCond.jpg]

I really don't care for the plastic in line socket connectors for several reasons so I opt to use metal. More expensive but in the long run cheap insurance. After stripping and soldering the wire, I use an adhesive lined heat shrink tubing to bond the outer jacket to the metal ground tab of the connector. This takes the stress and keeps it on the outer jacket and not the inner wires.

[attachment 236912 HeatShrinkInner.jpg]

These in line style connectors have a bad habit of the outer shell loosening up and that just drives me crazy, so I go to extra efforts to make sure that doesn't happen. And this is a case again to use a metal connector, you can use Thread Lock on it!

[attachment 236910 Thread.jpg]

Lastly the finishing touch. In the photo you can see a space between the cable and the hole in the connector. I don't like that, as dirt, water, sand etc. can get in there. By adding another outer sheath of adhesive lined Heat Shrink several things are accomplished. The space is sealed to keep the environment out of the connector, the Thread Lock is redundantly backed up to stop any loosening of the outer shell, and lastly but most important this creates an incredibly strong Strain Relief. This outer Heat Shrink is about 1/8 inch thick once reduced, it is very strong!

[attachment 236909 Outershrink.jpg]

I hope this has been helpful.

BB

 

[Digger]

Very Nice BB. Looks like that would handle the toughest situation. Thanks for sharing the detailed pics? HH Randy

 

[2000nkb]

Digger I made a couple of these and they work great. Just wanted to give you the kudos you deserve. Thanks!!!!!

 

[Rick(ND)]

I decided to find a 90 degree plug so it will not stick out so much and found a patch cord that was 12 inches long and had mono plugs on both end. Cut it in the middle and put stereo jacks on the ends, so I have 2 of them and they work great. I got the parts at Radio Shack part # 4202465 for the patch cord and # 2740141 for the 2 stereo jacks. Just thought I would let those that want to make one know the part numbers needed.

Rick