LittleMega
These ‘phones are similar to the others I’ve worked on in the past, but are a big step up. These can process your voice but also have a sound FX generator.
It makes CAR, SIREN and MONKEY sounds.
I started by adding a pitch adjustment to the voice changer and another one to the sound FX circuit.
Then I had to cut some connections and rewire some points to rerout the sound FX so that they would go through the processor.
I’ve also modified the circuit to give the user access to a “robot” voice changing effect. This effect is built into the voice changing chip but was not utilized in the original toy. 
SCHEMATIC
This schematic is incomplete. The drawing was made from some old notes I took while working on one of these. There’s a lot of lead cutting and rewiring in this piece if you want to patch the sound fx circuit into the pitch changer. Also you can rewire the pitch changer slider switch to include the “robot voice” effect.
I’ll try to update the schem to show how to cut and wire the circuit in the near future.
The sounds below were made using the self contained soundFX circuit processed through the internal pitch changer.