I want to add an adapter plug to my Russian Big Muff

[carnevoodoo]

Where can I find directions?

I am sure there's directions somewhere.  If not, how hard would it be, and can I do it myself?  

[Mark Hammer]

Don't they already come with one?  In which case I am assuming you mean you want to add an adaptor jack for a Boss-style barrel plug, right?

[carnevoodoo]

Don't they already come with one?  In which case I am assuming you mean you want to add an adaptor jack for a Boss-style barrel plug, right?

Not the Russian model.  It is battery only.

[morganpedals]

I use this - http://www.musiciansfriend.com/srs7/search/detail/base_id/54114/src=01340

It comes with an adapter that snaps onto the battery snap on pedals that don't have a 9v plug. It also comes with a dasiy chain for powering multiple pedals.

[Mark Hammer]

Hmmm.  I wasn't aware of that.

Probably the easiest way to install a wall-power jack is to drill a hole and install a 1/8" mini phone jack.  I realize  all those "other" brands use barrel plugs, but many of the E-H chassis are made of the sort of steel that is difficult to machine, so the smaller the hole the easier a mod.

An external power jack needs to do 2 things: it needs to switch BACK to battery power when nothing is plugged into it, and it needs to make sure that the right power leads are used.

You'll need what is called a "closed circuit" jack.  This has a small "tongue" contact which touches up against  the jack conductor used by the tip.  The RED wire from your battery connector will go to the solder lug for that little "tongue" instead of going directly to the board.  Run a red wire from the lug for the tip conductor to the board.  When you insert the adaptor plug into the jack, the contact between the tip and tongue will be interrupted, so that the board takes its power from the adaptor only.  When you pull the plug out, the contact between tip and tongue is resumed and the power line to the board is now drawing from the battery.

Make sure the adaptor provides V+ at its tip and V- on the shank/shaft of the mini phone plug, and make it a point to insert the plug of the adaptor FIRST, before plugging the adaptor into the wall socket.  The reason is that  there is a risk of things being shorted out while inserting the plug.  If you're careful, it is not a problem, but I imagine the reason why so many manufacturers opted for the barrel style jacks/plugs was that fuzzbox-toting teens were never the poster children for meticulous care.  If you hardwire barrel jacks to boards, they don't pose any extra cost to the manufacturer, but installing them after-market is a P.I.T.A.