ARP 2600 TONUS Modular Synthesizer

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Pics of the inside below.

"This early Tonus era ARP 2600 synthesizer had oscillator sync added at the factory and also had its keyboard upgraded to the later 3620 model, which is duophonic and includes an LFO. The factory also installed the PPC (proportional pitch control) - a very useful pitchbend and vibrato mechanism found in the later Odyssey and Axxe. There was also an additional gate input for the AR envelope added too, so this arp's 2 envelopes can be gated independently.

We meticulously disassembled, cleaned, refurbished and future-proofed this unit, sparing no expense - a process that took a whopping 60 hours of skilled vintage synth tech labor, plus parts costs. It's now working like new again and will hopefully be much more reliable than any other of its type out there. The value of this work is of course included in our price which is justifiably higher than lesser examples of this beautiful classic instrument often being sold by amateurs disguised as store owners on a popular website.

We did lots of maintenance and preventative work to this instrument, including the following: All tantalum capacitors were replaced, the power supply was rebuilt, the faders, jacks and switches were properly cleaned and are free of crackle, the keyboard was fully rebuilt with new bushings, keys removed and cleaned, the unit was recalibrated, replaced many terminals / molex connectors to greatly reduce the chance of connection issues, cleaned keyboard connector, key contacts and bus bars, replaced cinch jones receptacle, etc. There were a few other things done along with any necessary repairs.

The added oscillator sync makes it possible to make much more interesting sounds than any stock 2600 can. A CMS 4012 filter module, well known for its high quality sound, is installed in this unit. This 2600 has been tested systematically multiple times over many hours and is working perfectly and sure to make its next owner really happy!

Part of the extensive restoration process included re-coning the speakers. During final testing, we noticed what sounded like a slight distortion coming from the speakers that we determined was actually due to the 2 pieces of speaker cloth originally present in this unit between the speakers and the front panel, so we removed them and put them in a plastic bag which is now inside the unit in case whoever buys this unit wants them."