Replacing the 9v jack sockets on EH pedals?

[knealebrown]

Newbie question, (i think the answer may be yes, but lets find out)

i have a electro harmonix small stone and small clone that i want boss style 9v connectors on instead of those inconvenient jack style connectors, can i just simple swap them out and drill a larger hole?

any reply would be gratefully appreciated.

[theehman]

It's as simple as that.  I do it on Big Muffs pretty often when they come in for mods.

[Mark Hammer]

There are two reasons why one used mini phone jacks/plugs for supplying external power:

1) They are so much smaller and cheaper than the barrel jack equivalent.  Much more flexibility in where you can situate them, which makes them very 1590B-friendly.

2) There is never any confusion about which conductor is ground and which hot.  It's always tip-positive.

There are two reasons why people use barrel jacks/plugs:

1) There is no risk of shorting out hot and ground during insertion.

2) The same jack/plug can be used for outside positive, outside negative, and even AC.

The risk of using a phone jack is that a person needs to remember to always insert the plug into the effect pedal BEFORE they apply power or plug the wallwart in.

The risk of using a barrel jack is that some wallwarts are wired up outside neg and others are wired up outside pos, and explaining that the the general public (as well as being able to READ what it says on the wallwart and know which type it is - it's often very tiny print and hard to see) can be difficult.  Pedal-makers get around this by strongly recommending specific adaptors.

Personally, I use phone jacks for my own stuff, and if I make something for others who are committed to their Boss PSA and daisy chain, I use a barrel jack.

[knealebrown]

A reply from the man himself im truly honored  , i feel a little embarrassed for using the word inconvenient now 

btw what is the reason behind using the older style jack connectors over the more standardized BOSS style ones? i always wondered why EHX do that.

thanks for the reply.

[Mark Hammer]

In 1978-1980, if you used pedals, you most certainly did not use a pedalboard unless you were a Pete Cornish client.  And if you did use an adaptor, it was generally one adaptor per effect and the same adaptor you might buy at Radio Shack for your calculator (many calculators still needed a full 9v battery to power them).  And those adaptors came with a mini phone plug at the end.  Barrel plugs, while in use, were comparatively rarer than phone plugs at that time.  EHX simply stuck with what they were using then.  And, as noted in my earlier post, there are some very good reasons to want to use phone jacks/plugs.  I find it very easy to install a phone jack along the rear skirt of a 1590B (where it is most conveniently used) between the pots and circuit board.  Installing one of those bulky black plastic barrel jacks is much tougher.  For the homebrew crowd, there are only a couple of potential parking spaces for them, and with a 1590B most of those spaces are inconvenient.

In discussing power jacks a couple years ago with Bill Finnegan, who makes the Klon Centaur, I found he declined to go with barrel jacks, and stuck with phone plugs.  His reasoning was that he found the connections with phone plugs more secure and simply didn't trust barrel jacks.  In an effort to persuade him otherwise, I asked Steve Daniels if he could find a barrel plug/jack that addressed those concerns.  Steve, bless him, tracked down a style of barrel plug/jack made by Kobiconn that actually lock in place with a half twist.  Mouser sells them.  They're pretty dang slick!

[skrunk]

a mate has asked me if I can do this mod on his small clone so I've been looking around for some info on it.

if I put in a Boss style barrel jack, will the pedal then need a positive tip supply?
does this mean it can't be daisy chained with other neg tip pedals?

[Mark Hammer]

No.  You're confusing some things.

The physical shape of the two plug styles means different sections have to shoulder the responsibility of pushing one contact out of the way on the jack when a plug is inserted.  For phone plugs, this is always the tip (though occasionally the ring as well, but there we're getting more complicated than a standard 9v power jack).  For barrel plugs this is always the outside shaft.

What you want to aim for is identifying the two pins on the jack that normal short out together.  Then, insert a bare unconnected plug, and find out which one of those two lugs remains in contact with the shaft of the plug (touch your other meter probe to the appropriate lug on the bare plug).

THAT lug is what goes to V+ on the board.  The lug that gets disconnected when a plug is inserted is the one the red wire of the battery snap goes to.  The remaining lug is your ground. and should be connected as such.

[skrunk]

ah I get it.
many thanks Mark!

[knealebrown]

In my opinion this was a good learning exercise for me about a year ago. Grab your DM and start thinking logically about your jacks and where the signal flow in the power is. I Sussed it eventually and l also learned a lot.  nothing better that that moment when something clicks into place in your brain

[zombiwoof]

I just use these on my pedals with the 1/8" power jacks when I use a Boss-style power supply:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160410629837&ssPageName=STRK:MEWAX:IT

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130400035336&ssPageName=STRK:MEWAX:IT

Cheap, simple and keep the pedal in original form.

All US-made pedals in the old days used the 1/8" plugs (EH, DOD, MXR, etc.), Japanese pedals used the barrel plugs.  At some point, the industry adopted the Boss style plugs as a standard.

Al