More PAiA

Work has been unbelievably hectic, but fortunately in a good way. Apologies for the utter lack of updates. I've been working on a few projects but for the most part I've been concentrating on other things. If interested, I put some tracks and noises up on Soundcloud. There's really no reason to rush over there and listen, but you're welcome to if interested.

Here's some more PAiA pics. The project is essentially done for now as I'm moving on to the large DIY modular which I've been planning for some time.


If interested, the modules in the pictures are:

Top Left Wood Cabinet (left to right)
CGS Psycho LFO, Envelope Follower, 2720 VCA, blank, CGS DC Mixer
Second Row: PAiA Power Wing (altered for DC power in and mults), 2720 Function (Envelope Generator), blank panel, DIY octave divider


Top Right Wood Cabinet (left to right, then down)
Mixer (not built by me), 2720 Envelope Follower, 2720 Function (Envelope) Generator, 2720 Second Row:
2720 Power (with attenuater/mults/bias) , 2720 VCO, 2720 BPF


Left Paia Cabinet:
Top left to right
4711 Mixer, 2720 VCO, DIY Clock/Square Wave Generator, power in
Second Row:
4710 Balanced mod/VCA, 4720 VCO, 4720 VCO, 4730 VCF

Right Cabinet
Top Left to right:
CGS Steiner VCF, 2720 LPF, 2720 VCA, 4740 Envelope Generator, 4740 Envelope Generator
Bottom:
CGS BPF, 4750 Control Oscillator (LFO)/Noise, 2720 Envelope Follower, MFOS Dual VCA, MFOS VC Sample and Hold and CGS Real Ring Mod

I have a Condor and MFOS Wall Wart PSU. I prefer them to the oldschool PAiA power.

PAiA Documentation

I thought that it may be helpful to list where to find documentation for the 2720 and 4700 synthesizer. I'm going to link to the pages that the manuals/schematics are stored on and not the direct download.

2720-1 VCA (schematic only)
2720-2a VCO (schematic only)
2720-3B Band Pass Filter (schematic only)
2720-3L Low Pass Filter (schematic only)
2720-4 Function Generator (schematic only)
2720-5 Control Oscillator / Noise Source
2720-6 controller Vinyl Strip/S&H
2720-7 Power Supply
2720-8 Keyboard manual (13.6 MB)
2720-8 Illustrations Supplement (5.7 MB)
2720-9 Glide manual (5.9 MB)
2720-11 Envelope Follower
2720-11 Envelope Follower (schematic only)
2720-12 Inverter/Buffer
2720-12 Inv. Buffer (schematic only)
2720-14 Sine Converter/PWM (schematic only)

For documentation regarding building the 2720 modules read: Building the 2720 series modular.

Also:
Using the PAiA 2720 Synthesizer


4710 Balanced Modulator/VCA
4711 Mixer
4712 Reverb
4720A Voltage Controlled Oscillator
4730 Multi-Modal Filter
4740 Envelope Generator
4750 Control Oscillator/Noise (see PAiA 2720-5)
4761 Road Case
4762 /4782 Road Keyboard
4770 Watt/Power Block
4771 Regulated Power Supply
4780 Sequencer
4783 Joystick
4786 Velocity Touch Controller

Also:
Using the 4700S

Additional:
8781 Quad Addressable Sample and Hold (QUASH)
8785 Linear Digital to Analog Converter

If anybody has links to the scans of the manuals that I don't have please provide a link and I'll post them here.

My PAiA Modular and its Power Consumption

I was doing a little work on my PAiA modular today as I wait for the FaderLube to come for the ARP Axxe. I was rearranging the cabinet and making an auxiliary cabinet when I realized it would be very handy for me to make a list of the modules that I'm using in the PAiA system and how much voltage they need to be powered. Here's what my list looks like right now:

PAiA 2720 VCA: +18v, +9v
PAiA 2720-2A VCO: +/-9v
PAiA 2720-3L LPF: +18v
PAiA 2720-4 Function Generator: +18v
PAiA 2720-11 Envelope Follower: +/- 9v

PAiA 4710 Modulator/VCA: +18v, +/-9v
PAiA 4711 Mixer: +/- 9v
PAiA 4720 VCO (x2): 9v
PAiA 4730 VCF: +/-9v
PAiA 4740 Envelope Generator (x2) +18v
PAiA 4750 Control Oscillator: +18v
PAiA 4771 Regualted Power +/-9v, +18v

CGS04 DC Mixer: +/- 15v
CGS03 Psycho LFO: +/-15v
CGS30 BPF: +/- 15v
CGS35 Steiner VCF: +/-15v
CGS52 Simple Wave Folder +/-15V
MFOS Sample & Hold w/ White Noise: +/-15v

CGSRR Real Ring Modulator: Passive
Multiples (x2): Passive

Re-Wiring the PAiA 4771 Regulated Power

As some might remember from my two previous posts on 11/1/2009 and 6/1/2009 I had re-appropriated the 4771 Regulated Power panel after pulling the PCB. After using my own power source, I had decided to remove the 4771 PCB, which had some badly leaking electrolytic caps, and replace it with a MFOS Sample and Hold which was wired to a René Schmitz white noise circuit.

After reading through Brice Ward's (1975) book, I saw the value in the way PAiA distributed potential power to other modules. It's kind of quirky, yet useful. Therefore I've decided to re-hook up the board and replace all of the caps.

I'm not sure what I'm going to do with the Sample and Hold circuit. It's a really handy circuit to have in the synth. Originally PAiA had s Sample and Hold on their keyboard interface. Perhaps I'll include one on the interface device I'm planning now..

Telestar Box for PAiA 4711 & 4740

Been working on another CMOS box for somebody. Here's how it looks so far..















I'm trading this box for a 4700 Envelope and Mixer. The individual was actually kind enough to volunteer to send the modules before I finished his box. Here's some pics of the modules:












And back:


















That mixer is actually six inches wide instead of the typical two or four inches. That compounds space issues even more but it's quite a beautiful little module..

Here's a look at how the 4740 envelope generator works:

















And the 4711 mixer:

The Paia 4771 Regulated Power Supply and Distribution

Although I can see some advantages to the original Paia power distribution method the caps in the distro and PSU are leaking badly. If you look closely you can see some pretty electrolytic crystals.

Therefore, I got a Condor +/- 15V PSU and a DIY +/- 9V PSU and some CGS distribution boards. This should make things a bit more manageable. The 2720 and 4700 systems will run fine on 15V.

The power module panel will still serve as a great bias.

The 4700 distribution method












Power regulator which is leaking electrolytic fluid badly.















Most of the brown stuff on the side of these caps is the glue that was used to secure them into the cabinet. The reddish brown stuff on the top of the caps is not glue..


















Here's how the 4771 works..

About Pin Jacks (and Bananas)

I debated with myself (and others) quite a bit about keeping or losing the original Paia pins. On one hand its cool to preserve the integrity and original aesthetic of the synth (not to mention the time removing all the little buggers). On the other hand, they're the same size as banana plugs, they do look somewhat similar, and banana plugs are more useful to me in regards to my previous builds. Plus, bananas can be stacked so I can remove the pins and have more real estate to be creative with mods..

Finally I decided to go with bananas. Function over form. So I got down to the nitty gritty and removed these pins.

FYI There are adapters for Banana to pin plug that Mouser sells.


Here's a pic of a pin plug.





















Here's a comparison of bananas and pins. As you can see the holes are quite different in size but the jacks are similar.






















Here's what the legendary Scott Lee from Paia says (taken from the Paia Talk forums):

"The pin plugs aren't as readily available as the 1/8" phone plugs, but Mouser 800-346-6873 has them (stk #530-105-0302-1) but they describe them as tip plugs. Mouser has the rubberized test cable too. Solid, 14ga insulated wire wire with about an inch stripped off at each end can be used for the cv patches. Test leads as used on inexpensive multi-testers are often the right size. Since everything in the 2720 or 4700 series systems is on the same power supply, they already have a common ground, so the cables need only be a single conductor wire. When patching to the external equipment, or between a 4700 series analog keyboard controller, one cord will need to be patched between a ground circuit jack (could be a black one?) on the synth and the device ground to establish a common ground between them."

A Look At the Paia 4700

Here's a look at the Paia 4700