Dutch Synths

  • Model:         Syntovox 221 
  • Bands:          20
  • Retail price   6000 Euro
  • Produced:     ?
  • Size:              4 HE
  • Features:     High end model with noise & VCO, matrix panel, voiced & unvoiced inputs, attenuator per channel.

Expander 1220

The 1220 vocoder expander unit pictured above this 221 is a one-off piece Synton built for Dutch broadcasting company NOS. It houses a pitch to voltage converter, CV freeze function and a ‘presto-patch’ edge connector for making analyzer-synthesizer patches

A spectrogram of the 20 filters, spaced in minor thirds.The four bands per octave create a diminished chord.

Track name Artist name
00:00/ 00:10

The sample below is a polysynth chord on carrier, a S&H sine on the speech input.
One channel is without voiced/unvoiced detection, the other switches to internal noise on unvoiced sounds.
The left and right sounds are recorded in different passes.

Track name Artist name
00:00/ 00:10

Used parts
TDA 1034/NE5534

Syntovox 221 Manual,    Review 221 sono france

VCO 221 schematics221 PSU schematics 221,_input schematics 221, Vocoder output mixer,

Only a small amount  of these were made. Users include Wendy Carlos (who owns a 221 & SPX 216), 
Bruno Spoerri, various electronic studio’s in Europe.  Best suited for studio use due to complex control.
The 221 has a 50-pin connector on the back which provides CV in and out for each channel,
and other functions.


Block Diagram 

Some  tech tips
The filters uses MKM Caps, Sometimes the connections of the caps became loose.  You can try to solder these
There are tantalium caps used.  They can cause shorts at the power supply. You can replace these by normal caps 
or 35 volt tantalium caps 
In earlier versions the dual regulator xr4195 is used.  At the two middle pcb brds.  These can be broken
There are a lot of quad opamps,  If a opamp is broken most of the time the output is one of the power line.