Serviced ARP Pro Soloist Vintage Analog Synthesizer Keyboard

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via this eBay listing

"The ARP Pro Soloist is a classic preset-based analog synth famous for its expressive, assignable aftertouch that lets players control vibrato, brilliance, growl, and more with incredible nuance. Heard on legendary hits from Genesis and P-Funk, it delivers instantly recognizable 70s tone in a compact and performance-ready design. This synthesizer has the ARP 4034 Voltage Controlled Filter, a very fat 4 pole low pass filter that infringed on Moog's ladder filter patent.

This ARP Pro Soloist is in great condition, with strong silkscreen present on the case, which is rare. This instrument used to belong to the San Francisco City College and there is an asset tag on the back and a "CCSF" scratched onto the front panel, please see photos. This synthesizer was serviced by Synthchaser (the top expert on ARP Pro Soloists) in September 2025. Work done included:

Synthchaser Precision LED slider upgrade. The old original sliders have been replaced with new, smooth, high precision LED illuminated sliders. The difference in the way these sliders feel and perform compared to the originals is a huge improvement. I can disable the illumination for the buyer before shipping, upon request at the time of purchase

New aftertouch sensor - The original aftertouch sensors are a common failure point and the aftertouch effects are what makes this synthesizer so expressive--I replaced the aftertouch sensor with a new long-lasting one to ensure the aftertouch will work for years to come.

Keybed refurbished - New key bushings installed, buss bars cleaned and key contacts cleaned & adjusted

Power supply recapped

All tantalum capacitors replaced (except those in the sealed 4034 VCF submodule)

All voices working and sound correct!

All touch sensor effects working!

1/4″ output made High – ARPs of this era had the 1/4″ jack as the low output. As the low output is too low for most, the 1/4″ jack has been made to a second high output."