For sale is a vintage ARP Pro/DGX Mk. I, aka the Pro Soloist III.  This is the model to get!  It has the same sounds and fat ladder filter as the Pro Soloist, but with more reliable and more performance friendly pushbutton voice selection switches.  This keyboard is the sound of 1970's Genesis.

This synthesizer has just been serviced by Synthchaser, the top ARP specialist - recapped, new key bushings, new LED sliders, new aftertouch sensor, new Synthchaser linear power supply, fully functional, calibrated and sounding great. 

I have video demo of the actual keyboard being sold (at the end of the pictures list on Reverb)

OK cosmetic condition, someone at some point scratched their name on the front panel (see photos).  There is some black tape on the rear panel which may be covering something similar (I haven't peeled it back to check).  Original fiberboard bottom panel was missing so a new replacement was made.  The octave transpose switch can be a bit touchy switching into the "Down" position and may take a couple tries to get it to work correctly (see video for more details on this).  This keyboard was serviced in March 2024 by Synthchaser, work 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--we replaced the aftertouch sensor with a new long-lasting one to ensure the aftertouch will work for years to come.
  • Action restoration - New key bushings installed, keys removed and cleaned, buss bars cleaned and key contacts adjusted
  • New Power Supply - the original power supply was missing, and replaced with a custom linear power supply designed and produced by Synthchaser. 
  • Tantalum capacitors replaced - All the failure-prone tantalum capacitors in the synthesizer have been replaced to ensure stable operation for years to come.
  • Synthchaser 4034 Voltage Controlled Filter Submodule -  This is the infamous “Moog lawsuit filter”, the 24dB/octave ladder filter that was heavily based off of the Moog ladder filter.  This is a very fat sounding 4 pole filter.  Synthchaser modules are true to the original designs and professionally built using premium components with superior performance and reliability to those found in the original modules.
  • New bottom cover panel
  • 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. 
  •  Aftertouch and all aftertouch effects working great: Volume, Wow, Growl, Brilliance, Volume, Vibrato

Local pickup in San Diego is welcome and encouraged!  Contact me for an appointment to try out the keyboard before you buy.  This is a vintage electronic item, so all sales are as-is and final.  The keyboard will be packed well and insured for the full sale price.  Visit the Synthchaser YouTube channel and rest assured that high quality detailed work was performed on this synthesizer by the expert on these instruments!

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Listeda month ago
ConditionVery Good (Used)
Very Good items may show a few slight marks or scratches but are fully functional and in overall great shape.Learn more
Brand
Model
  • Pro/DGX 37-Key Monophonic Analog Synthesizer
Finish
  • Black
Categories
Year
  • 1977 - 1980
Keyboard Action
  • Synth Action
Analog / Digital
  • Analog
Polyphony
  • 1 Voice
Number of Keys
  • 37 Keys
Key Size
  • Full Size

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Synthchaser

San Diego, CA, United States
Sales:105
Joined Reverb:2016

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