I received a email recently requesting more info & pics about the EML 300.
This is a very unusual controller. It was manufactured in the early 70s by Electronic Music Labs of Vernon, Connecticut. Made in limited quantities, it was designed to compliment the EML 200 & 400.
The telephone type keyboard is really just a collection of 16 keys that trigger the corresponding voltage on the dials. The actual numbers don't correspond to anything (as far as I can tell). Maybe this was a surplus telephone touchpad ???
The VCO has 2 ranges: Audio (HI) & SubAudio (LO) with a continuously variable wave shape which shifts from triangle to square & saw.
To the left is a frequency modulation input (labelled vibrato).
DC (Direct Coupled) coupled affair.
It's prewired to the AD envelope generator (below) but can be modulated with more complex EG's like those found on the EML 400/4001 & EML 200.
Of course external audio (other than the built in VCO) can be patched in too.
The Sample & Hold can be triggered from the LFO or the Matrix Keyboard.
The LFO is a triangle wave.
The EML 300 controller is extremely rare. I'm not sure how many were manufactured & I haven't seen another example of one. However, there is a Brazilian company (EMW) making very similar controllers inspired by this design.
The EMW (Electronic Music Works) 300 is quite authentic. Up until the time when I finally found a EML 300 I used the EMW version successfully with my EML 200.
The matrix is now a 16 step sequencer.
And as with the vintage EML 300 each rotary knob adjusts a voltage that appears on the Voltage outputs when you press the corresponding key.
The joystick of the EML has been however replaced with a what EMW call a manual switch module.
It's basically a router with a 5V pulse out - useful for transposing pitches.