CGS 26 Wavemultiplier 

 

 

This is another veroboard lashup 

 

 

Mounted on rear of Scheaffer Panel 

 

 

OK. Not so tidy, but at least it works! 

 

 

A bit neater round the front 

 

 

Jacks and pots wired up 

 

 

Completed module 

 

This is the Wavemultiplier featured on Ken Stones site. 

 

I have replaced the LM324 quad op-amp specified for IC4 with a TL074. This has the effect of sharpening up the transients on the pulse output, producing more rectangular waveforms.  Basically the slew rate of the TL074 is 26x faster than the 0.5V/uS of the LM324 which tended to produce triangular waveforms at moderate frequencies. 

 

Here's some 'scope shots (not too well focused, I'm afraid) of a 410Hz triangle wave fed to 'TRI IN' and the resulting folded out and pulse out. 

 

 

Top trace 'FOLD OUT'  

Bottom trace 'TRI IN' 

 

 

Top trace is the same 'FOLD OUT' 

Bottom trace is 'PULSE OUT' with LM324 in position IC4 

Notice the slew limiting in the bottom trace. 

 

 

Here's the same thing again, but this time the LM324 has been replaced by a TL074. 

The pulse output is much sharper. 

 

As IC2d is going spare in the current circuit, it should be possible to utilise both the TL074 and LM324 for the pulse out, and just switch between them with a toggle, which would then feed the 'PULSE OUT' jack. This would give a 'hard' or 'soft' pulse out. I haven't implemented this yet. 

 

When manipulating the folds, offset and PWM with external CVs, it's possible to get very animated timbres from this module. 

 

Sound clips to follow. 

 

 

Here's the Wavemultiplier installed (top right) 

 

My version of the Scheaffer front panel data is here 

 

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Page last updated 15th March 2005