How to Circuit Bend/Modify a Cheap Sampler :

modifying or bending an inexpensive "30 second greeting card sampler" adding Pitch, CV, Looping, Triggering, Input, and Output.

I noticed recently when searching for something else that a site had '30 second greeting card sampler'(s) for less than two (2) $USD!!
And IMMEDIATELY I started thinking: "There has to be a way to use that to make noise (aka music)".  So I 'offered' even less for a larger number.  I think I bought 4, although I'm not exactly sure because I ended up buying some more later once I messed up a couple of the original ones.   These Greeting Card Samplers or Greeting Card Voice or Message Recorders are available all the places you'd think they are like Amazon and Monopo-Bay as well as numerous marketing and advertising sites who sell them along with things you can put your business' name on to promote it.  They are priced in a fairly large continuum from 2 to 20$.   It's not hard to spend a couple of minutes and find them for even less than 2$ if youre looking for more than one.
Anyway, Here's what you get when you buy one of these:

30 second voice / message greeting card reorder

It's a small PCB with 2 tactile buttons (not shown in pic above) for 'play' and 'record', a generic miniature electret mic, cheap 8 ohm speaker, and 3mm red LED.  Unfortunately, the IC is covered with the good ole total bullshit black gumdrop so your guess is as good as mine on that.  Also included are 2 1.5v el44 hearing aid batteries.

Bending/Modifying

The first thing to take into account here is that ALL the wires are TOTAL shite  - I mean we're talking so bad that the first two ones I was messing with I wrote off because I thought they were DOA when it was just shorted wires on both.  When I was going through the board looking for the bend points I wanted, it was pretty normal for me to have to stop and 'jiggle' the wires until I found whatever one was shorting out that time and got it to function again.  So,
-Step 1 is to remove all the wires after noting what is what and where it went (from here out, order is arbitrary so you can do things in whatever order you prefer)

-Step  2 replace the batteries (if youre going to do this at all)
I've had a LOT of different values on these, its pretty much the only thing that varies among the boards sold as 'greeting card message recorders'-some are 6v brought to 5v by a voltage regulator and some are 3v etc.  In this case, this board runs on 3v (1.5v x2).  Note : you cannot always just add the battery voltage together. Most times yes, but sometimes the batteries are run in different ways.  

For example, If you just connect the pos to pos and neg to neg then the voltage stays the same. Its only added together when they are connected in pos-neg series-or when opposite polarities are connected to that current flows from one to the other.

click for larger version

Step 3 Add SPDT/transistor to loop the sample : Since these type of 'message recorders' are built to be triggered by a button press and need to be re-pressed (you can't simply hold down the button) -you can't just connect a toggle switch to the tactile momentary switch wires so that the connection is constant.  That would just result in a single play of the sample and youd have to switch the switch down and then up again to play it again.  The solution? Use a transistor to re-trigger over and over.
How do you do this you ask? Well, in this case I used a NPN transistor (meaning it has a Base middle leg, collector and emittor outer legs), which basically connects the two outer legs whenever current  (in this case I used a 2n2222 but any other NPN will work..probably) changes on the middle leg.
Since I needed to switch this on and off I stuck a SPDT toggle in between the middle leg and the source of trigger (the inner LED pad).  Since there was another lug on the toggle to use, I simply connected it to the tip of a audio jack so that incoming current (like CV) can be used to trigger the loop as well -as an added plus.

Step 4 adding an out (or keep the speaker, or add a switch and have both!) As noted in the photo above, simply solder two wires where the current speaker wires are.  However, its important to add a small resistance resistor (4.7ohm to 22ohm) in between the two connections on the out jack to cut down on the gain some-otherwise its going to sound like youre intentionally blowing the speaker all the time when you plug it into something.  NOTE: the polarity of the connections in the photo is just a guess, I can't remember which is pos and which is ground.  Just try for yourself-youve got a 50/50 chance so it should be easy to figure out!

Step 5 adding a Pitch Mod to alter the pitch of the sample/loop play
I used a 500k potentiometer, but almost any will work.  Try whatever sounds good to you and see what you like. You may also want to leave in the original resistor you connect the two leads (from the wiper and outside lug-whchever it doesnt matter which really-of your potentiometer) on either side of.  Anyway-see above photo for exact location of the clock resistor.  What youre doing here is a standard circuit bending trick-hijacking the clock for the circuit.  Its what tells the circuit how fast to play the sample.  In this case its a resistor but it could be a crystal or all sorts of stuff -its just a resistor in cheap stuff cuz thats the cheapest option.
So, by changing the value of the clock resistor, were changing how fast the circuit is being played, and thus, its pitch.

Step 6 adding an IN : simply connect the red (pos) line to the electret mic to the tip of a jack and the black (ground) to the sleeve lug and you're good to go! you can also either add a switch and keep the mic or keep both wired in if you want.

Here's my finished bend (first time I did it anways so kinda messy):