Moog Music Forum

There were a few minor changes to the Minimoog during its production run but the biggest and most significant change during production was the 3 different versions of the oscillator board that were used. R. A. Moog started the manufacture of the Minimoog while the company was still in Trumansburg, N...

The Technical Service Manual for the Moog Modular System can be downloaded from several sources and it contains the adjustment procedure for tuning the 901A and 901Bs. If you follow the tuning instructions exactly I think that you will be OK but the more knowledge and experience in electronics you h...

Additional photos, this is after completion of the work.

A number of years ago I bought a large batch of Moog related parts and pieces from an Ebay seller. I got several boxes of transistors, wirewound trim pots, capacitors, jacks, C-frames, some blank panels, etc. I also received parts for a 921 VCO consisting of a front panel and two circuit boards, and...

The question was raised as to how old this module was, I can tell you that I own an R. A. Moog 904-B with s/n 1182, manufactured 12-69 and it looks identical to this one including the circuit board layouts. One minor difference is, the module in the photos appears to have several electrolytic capaci...

I am missing the following: Two CP3A panels 907A Two 902s 921A I also don't have a full complement of oscillators but I'm leaning towards making my own but havent ruled out just buying them. Although there are at least two companies that are making Moog module clones they are not exactly identical t...

I would like to obtain a few Moog modules to complete a vintage System 35 that I own which is missing a few. It looks like Synth-Werk and COTK are pretty much the only sources for module clones currently, and MOS-LAB has stopped making Moog modules. Are there any others out there?

I completely agree on your thoughts regarding the reissue of control voltage circuitry. An argument can be made about keeping the design of signal generating and signal processing circuity exactly the same as the original as it could theoretically affect the sound of the instrument, but control circ...

I recently bought a new Sequencer Complement B. Others have posted on this forum on the build quality of Moog's current modular products and I thought that I'd add a few comments of my own here. With the exception of the use of panel pots that were made by Alpha I think the overall construction is q...

I solved the keyboard drift problem by replacing the entire keyboard circuit with a digitally scanned CMOS based circuit which I designed and built. It has 3 narrow PCBs under the keyboard itself which is the scanning section and a small PCB where the original keyboard circuit was, that board contai...

Yes, the 08-001 VCO drawing and the later design using the ua726 are well documented and well known. Many years ago I ran the service department at a large music store that was also a Moog dealer and I accumulated a large number of drawings from Moog, ARP, and others, all of which I still have. Some...

I'm sure I know where that 901B updated design came from. In late 1970 Jim Scott and Bill Hemsath were designing the first two Minimoog prototypes. The first two designs used surplus or junked circuit boards including 901A's and 901Bs that were laying around at the Moog factory. The design team knew...