what have I done? Metal jacket DC Jacks?

[motterpaul]

I ordered these jacks from eBay:

http://www.ebay.com/itm/10pcs-5-5mm-X-2-1mm-DC-Power-Supply-Metal-Jack-Socket-/250779770172?pt=LH_DefaultDomain_0&hash=item3a63a39d3c

But here is the kicker - while the jack is fine on its own, when you mount it to a metal enclosure the ring (positive in most of our effects) makes contact with the enclosure, which is ground for most other components. This means + gets tied to - and you short out your voltage supply.

The polarity is correct - they work until you mount them. The key is that it is a "metal jacket" socket.

Now, I am contemplating just throwing these away but I realize I could use them if I had a set of all negative effects - like fuzztones. But even though you could make those effects work - you would have problems if you tried to mix effects. So, I would rather just build voltage inverters for fuzztones.

What would you do - throw them away?

[Silver Blues]

Ooh you've made one of the classic mistakes we all make in the world of DIY effects with those jacks  This is precisely the reason why, because the body is tied to the sleeve. They make for easy grounding in tip-positive applications but are useless here. I wouldn't throw them away, save them for some other non-effects- related projects.

[motterpaul]

Man, I did. The good thing is they only cost $2.88 for 10 of them (but I order 30) but it could have been worse, I could have paid $.67 apiece.

Anyway guys - DON'T DO THIS. Always buy DC jacks that are isolated from the casing.

It only took me a couple of hours to figure out the problem (duh!).

[alltrax74]

I've also been there
The only way to go is to use plastic washers or to buy some isolated ones

[motterpaul]

The right plastic washers would work, but they have to be the exact size because there is a plate-like area there that goes flat against the enclosure (in addition to the threads that go through it), plus there are not too many threads.

But that is actually pretty good idea - especially since these things are nice & small, and the price was right. Thanks for the brainstorm.

[alltrax74]

Actually I made my washers with a plastic bottle of water
I used that kind of tool for the inside hole and cut the outside with cissors
It worked pretty well but to be honest I quickly ended buying isolated ones

[Ed Nice]

The older you get, the more times you f**k up :p

I think it's that you actually make less mistakes than when you were young, you just tend to admit them and tell people what a doofus you've been whilst enjoying laughing at yourself! I do...

The first order I made for kits said I needed various things, including LEDs and I bought some of these, as they were the only LEDs I could see on the website. I was so excited, I didn't read the description :o http://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=172_184&products_id=1398

Anyway, you could get some gromits and some small bore pipe as a spacer? I am on the lookout for some small bore pipe to space my DC sockets so they stand out and give me a little more board room. I believe you can get stand out DC sockets, but where's the fun in that? As Heath Robinson famously said, 'I didn't get where I am today by taking the easy option'. It may have been CJ from Fall/Rise-Rise/Fall of Reggie Perrin (The) who said that but Heath Robinson is better suited to my analogy so we'll persist with him for the purpose of this post.

[motterpaul]

Ed - you said...

"The older you get, the more times you f**k up. I think it's that you actually make less mistakes than when you were young, you just tend to admit them and tell people what a doofus you've been whilst enjoying laughing at yourself! I do... "

Finally someone understands me   I always admit my mistakes because I truly believe it is a way for other people to learn what not to do. But I am never ashamed of the fact that I make a mistake, that is how we learn.  

In any case - I wanted to say I DID find a GREAT APPLICATION for these adapters. I was modding an old DOD compressor where he wanted a Boss-style jack (it originally took a mini-plug). Well, guess what, I needed one of the metal-jacket connectors because the pedal was designed to ground the audio output jack through the case.

Nothing else would have worked - lesson learned and great and simple answer to what seemed to be a pretty big challenge at first when the first Boss-style jack I tried gave me tons of hum.

[dexxyy]

motterpaul wrote

Ed - you said...

"The older you get, the more times you f**k up. I think it's that you actually make less mistakes than when you were young, you just tend to admit them and tell people what a doofus you've been whilst enjoying laughing at yourself! I do... "

Finally someone understands me   I always admit my mistakes because I truly believe it is a way for other people to learn what not to do. But I am never ashamed of the fact that I make a mistake, that is how we learn.  


As the old saying goes...... The man that never made a mistake never made anything.


In any case - I wanted to say I DID find a GREAT APPLICATION for these adapters. I was modding an old DOD compressor where he wanted a Boss-style jack (it originally took a mini-plug). Well, guess what, I needed one of the metal-jacket connectors because the pedal was designed to ground the audio output jack through the case.

Unless it`s a positive ground circuit then surely your shorting to ground

Nothing else would have worked - lesson learned and great and simple answer to what seemed to be a pretty big challenge at first when the first Boss-style jack I tried gave me tons of hum.

In theory the enclosure would be grounded via the ground on the input jack, quite a few older pedals worked on this principle which was fine till either jack worked loose. Far from being a pretty big challenge, a simple earth wire to the jack ring would suffice.

[Beaker]

"The older you get, the more times you f**k up. I think it's that you actually make less mistakes than when you were young, you just tend to admit them and tell people what a doofus you've been whilst enjoying laughing at yourself! I do... "

Wise words there mate!

I too have a load of these metal sockets. I kicked myself when I found out they were no good for most builds. I use them for all my PNP builds, so no harm no foul.

[motterpaul]

dexxyy wrote

 In theory the enclosure would be grounded via the ground on the input jack, quite a few older pedals worked on this principle which was fine till either jack worked loose. Far from being a pretty big challenge, a simple earth wire to the jack ring would suffice.

I know, one would think, but in this case that did not work. I tried running a ground wire from the DC jack to there and several other places and no one place cleared up the problem. It seems a lot of things were connected solely by the case, not just the output jack.