PPG 303 VC LPF


PPG 300 Modular

Introduction In August 2020 I bought a set of Behringer System 55 modules, as my first journey into Moog modular. My plan is to recreate the Klaus Schulze IIIP synthesizer and Dual Sequencer setup that Klaus bought on 22nd December 1975, and used successfully for many years. Whilst the Behringer modules cover most of the Moog modules I need, there are a few additional modules and changes I have made.

PPG 303 LPF Klaus added a full set of PPG 300 analog modules and two PPG analog sequencers in 1976, and placed them on top of the Big Moog, where the ARP 2600 and EMS 8 Octave Bank usually lived. The PPG setup replaced the Synthanorma SQ312 analog sequencer, and his ARP 2600 in the live rig. He kept the PPG Modular setup until he moved onto Digital synths in the early 1980’s, and seems to have sold them quickly, whilst the Big Moog survived in his studio until 1996. The Moog IIIP only has a few filters, so I am sure Klaus enjoyed the additional PPG sounds.

PPG 303 Artwork

AMSynths PPG 303 There are two types of PPG modular filter; the 303 VC Modifier with a 24dB transistor ladder filter (and a VCA) and the 317 VC Filter, which looks like a combined 904A/B/C. There are no schematics, so I have assumed the LPF is the same as in the PPG 1020, which sounds amazing! It is very similar in design to the traditional ladder filter as used in the Mini Moog.

The AMSynths PPG 303 module retains the original PPG design, with the addition of input and output buffering Op Amps, to ensure I get the right voltages into the core. The filter uses 33nF 1% polypropylene capacitors in the ladder, as a replacement for the 1970’s Tropical Fish capacitors that were popular at the time. The panel is 8 HP wide and printed in black and white to match the Behringer designs.

 

 

 

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