Discussion about the Korg PolySix synthesizer

This sounds really interesting and I'm tempted... but...
I assume there's no chance of hearing a good quality before/after recording with identical patches played identically? :P
I want to judge the noise level myself before tearing things apart :)

BR,
Peter

  ----- Original Message ----- 
  From: Oakley Sound 
  To: PolySix@yahoogroups.com 
  Sent: Friday, July 12, 2013 6:37 PM
  Subject: [PolySix] Making the P6 brighter


    
  I've been following Chip's progress with interest. And his recent post 
  on the dynamic noise reduction filter on the effects board spurred me 
  onto to investigate further. I too have noticed that the P6 is somewhat 
  duller than other synths and I had always assumed that with the ensemble 
  mode off the output was as bright as it could be.

  Chip's findings that all four ensemble modes pass through the DNR filter 
  was something I hadn't really thought about before.

  http://synthhacker.blogspot.co.uk/2013/02/mystery-circuit-polysix-post-effects.html

  In summary: the P6 has a 12dB/octave low pass filter that is set to 
  around 600Hz (the actual value depends on whether the BBDs are engaged) 
  when no notes are playing. This filter opens up when it detects audio 
  from the voice card. As Chip noticed it takes a finite time for the 
  filter to open and the filter doesn't always open fully in all cases. I 
  measured the filter took up to 100mS to open fully. That's a significant 
  loss of high frequency sound at the start of each note.

  Yesterday I went a stage further than Chip. Chip's mod basically forces 
  the filter open. I decided to remove the filter from the circuit 
  altogether. This has the advantage of no dynamic filtering (which is of 
  dubious amenity) and reduces the circuit pathway that the audio has to 
  go through. The LM13600 isn't a hi-fi part and removing it improves the 
  signal quality.

  The mod:

  Remove links J28 and J29. Remove R115 and R109 (which disables the 
  envelope follower). Remove C73 and C61.

  Link out, with a piece of solid core wire, the two left hand holes of 
  J28 and J29. Now connect with a piece of insulated wire the lower of 
  these now filled solder pads to the lower pad of C73. The filter is now 
  bypassed.

  Link out, with a piece of solid core wire, the two holes of C61. This 
  capacitor serves no useful job that I can see.

  Result: the P6 can be as bright as any synth. Percussive sounds ring out 
  where they didn't before. String sounds are really very majestic - you 
  can really pull off sounding like a string machine now. The slight 
  increase in background hiss is not a problem for me.

  Tony

  http://takla-makan.bandcamp.com/
  http://www.oakleysound.com


  

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