Good information Paul. I can add a little to this. Korg also used this chip in their first sampler - the DSS-1. The entire voice board in this hybrid is analog except for the A/D + S&H for CPU control of the VCA/VCF and digital delays. BTW, in the Korg DSS-1, they did use both the 12 db and 24 db outputs and used an external analog switch to select which of these went to the VAC input. Here is information I can add to what Paul has already given: Pins 1 and 2 are indeed CV level controls for two input signals (pins 20 and 21). However, they control the signal prior to the VCF like an input mixer to the VCF. I believe they do give a log response to a linear control. In the DSS-1, voltages at this pin are 0v = 0% volume, 3.83 volts = 50% volume, and 7.65 volts = 100% volume. I have not checked the actual signal level. But, to my ears, I am getting the correct response using a linear control voltage. Those are the voltages produced by the CPU + D/A + sample and hold. Pin 9 VCA LIN is actually used for total VCA level in the DSS-1. The noise source is external and is applied to pin 19 (VCF signal IN). I do not see any internal control of this level in the VCF section. If it is there, I am missing it. If I am reading the schematic correctly, in the DSS-1 the noise source level is controlled externally prior to being applied to pin 19. Pin 12 Vee is also -5 volts in the DSS-1 Pin 22 Vcc is actually +12 volts in the DSS-1 Pin 13 VCF cutoff LIN CV is not used as a control point in the DSS-1. It appears to me to be a trim-able temperature compensation circuit. So, apparently the 2069 needs that for accuracy of the VCF freq. Pin 14 VCF cutoff LOG is used for all VCF control in the DSS-1. But, all voltages are generated by the CPU + D/A + S&H. So, the cutoff control and (apparently) linear envelopes are added together in the CPU and sent to this pin via D/A + S&H I think Paul has a type-o below since his pin out list does indicate that pin 6 is the -24db filter output. It appears he meant to say pin 14 (VCA log) is tied to ground. So, in summary everything I have learned about this chip so far suggests that you have 3 signal inputs at pins 19, 20 and 21. Pins 20 and 21 mixed under external CV control. Those are summed with pin 19 (no internal level control) and all 3 are direct inputs to the VCF. VCF signal outputs are pins 5 (12db) and 6 (24bd) which in my case are connected via external analog switch to the VCA input at pin 7. PIN 8 on my schematic is listed as "CB" (something I do not yet understand) It is connected with a cap and diode over to pin 9 which is the linear VCA control. The VCA control is for all signals as all sources were already mixed prior to the VCF. It is interesting to see pin 8 listed as the LOG CV. I'm glad to have that new information (new to me anyhow). Pin 10 is the VCA audio output, but I show pin 11 as the audio ground. In any case, it is tied to ground. I have been playing around with this chip for a while and I am still in the learning process. Why? Because the DSS-1 is one of my beloved machines and I have a spare one I can hack on. I hope this additional information was useful. I hope to have more later, including a project where I plan to make use of this great little chip. But, right now my day gig is trying to kill me, so I am behind on all things synth related. Larry Hendry -----Original Message----- From: owner-synth-diy@dropmix.xs4all.nl [mailto:owner-synth-diy@dropmix.xs4all.nl]On Behalf Of Paul Maddox Sent: Wednesday, May 11, 2005 3:33 AM To: SynthDIY Subject: Re: [sdiy] NJM-2069 (Another Korg IC) Johannes, >> Btw, I remember there was some page about the NJM-2069 (Poly-800 and >> others). I think it had a pin-out, and some mentioning that you could >> get either 12 dB/oct or 24. I can't find anything anywhere! Has Korg >> shared any information on this chip? The best schemctaic example is the DW8000 schematic, thats on the web somewhere, you can see the 12dB output just isn't connected (what a waste!). Here's what other info I have - ---------------------------------------------------------------------------- -- I'm tempted to think that the pins labled "Level 1 & Level 2" (Pins 2 & 3) are the Log CV's for Osc1 & Osc2 VCA's respectivley. I imagine "Pin9" (VCA LIN), is the Linear CV for the Noise Source, maybe the Level + EG3 CV's are summed together into this Pin. Pin 6 (VCA Log),is tied to ground. This at least, is the Log CV for either the OSc1/Osc2 or Noise. So, thats one down at least. ---------------------------------------------------------------------------- -- KORG NJM2069 Pin# Function 1 Audio In GND (GND) 2 Mixer Signal 1 Level CV In 3 Mixer Signal 2 Level CV In 4 VCF Resonance CV In 5 VCF 12dB/oct Audio Out 6 VCF 24dB/oct Audio Out 7 VCA Signal In 8 VCA Level CV Log In 9 VCA Level CV Lin In 10 VCA Signal Out 11 Vss (GND) 12 -Vee (-5v) 13 VCF Cutoff CV Lin In 14 VCF Cutoff CV Log In 15 VCF cap C4 16 VCF cap C3 17 VCF cap C2 18 VCF cap C1 19 VCF Ext Audio In 20 Mixer Signal 2 In 21 Mixer Signal 1 In 22 +Vcc (+5v) Chip has separate *VCA with in,out and lin&log CV ins, *VC Mixer with two audio inputs, two CV ins for each input level control, it's output is hardwired to vcf audio in (no ext pin here), separate gnd for input signal *VCF with separate ext audio input (in addition to hardwired input from vc mixer), output, lin&log cv ins, four pins for integrating capacitors, vc resonance with pin for res cv This is almost half of synt-chip type just like old CEM chips, but sounds much fatter IMHO. Short look at pins 5/6 reveals easy mod for poly800 to get 2/4 pole filter... Poly800 misuses it's vca for adding 3rd vc audio channel to the mix as 'real' vca control is performed digitally inside osc chip driven by soft envelopes. ---------------------------------------------------------------------------- -- hope that helps. Paul