This ARP Quadra has just been professionally overhauled by
Synthchaser, the foremost expert on ARP Quadras! Work done included new
red LED sliders (illumination can be dimmed or disabled by control of a knob
mounted just inside the synth), recap of all tantalum and electrolytic
capacitors, new touch sensor, keyboard refurbishment, new IC chips, and more
reliability enhancements!
Here is a video demo of the actual keyboard being sold:
While many synths are listed as "serviced" or
"fully serviced", they are usually devoid of any details of what was
actually done. Those that do provide details or service invoices often
reveal that the synth was merely superficially serviced, and not genuinely
"future-proofed". I have not only serviced this Quadra, I've
taken it down to the chassis and overhauled it. Work done included:
- Synthchaser Precision LED slider upgrade. All 35 of 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. A pot (located just
inside the synth--nothing was drilled to the outside) can dim or disable the
illumination. With the LED's disabled,
it looks close to original, but these slides perform so much better!
- Illuminated slider caps - Slider caps with a translucent
plastic stripe that allows the LED illumination to shine through, while giving
you something substantial to grip onto. They look and feel awesome!
- Power supply rebuilt - All tantalum and electrolytic
capacitors in the power supply have been replaced, and high quality, high
temperature 105 deg C capacitors have been used for the power supply filter
capacitors.
- All polarized capacitors replaced - The tantalum capacitors
in ARP synths are ticking time bombs, and 40 year old electrolytic capacitors
are past their prime. All of the 150+ tantalum and electrolytic capacitors in
this synth have been replaced with new electrolytics to help provide stable
operation for years to come.
- 4075 Filter Enhancement - The ARP Quadra uses the same 4075
filter submodules found in the Odyssey, Omni, Avatar, and Pro DGX which was
designed with a calculation error that limited the cutoff frequency. Both
of the 4075 filter submodules (for the lead synth and the poly synth) have been
recapped, and corrected to provide superior frequency response, and tested for
proper operation in the Synthchaser custom test fixture.
- New aftertouch sensor - The original aftertouch sensors are
a common failure point-- the aftertouch sensor has been replaced with a new
long-lasting one to ensure the aftertouch will work for years to come
- Keyboard rebuild - Keys removed and ultrasonically cleaned,
buss bar and key contacts cleaned and adjusted
- Oscilloscope calibration - Calibrated to factory spec using
oscilloscope and frequency counter.
- PCB Interconnect reliability upgrade
- Many connectors replaced
- Batteries relocated - ARP Quadra presets are preserved by
alkaline batteries mounted to the microprocessor circuit board. In the
majority of Quadras, these batteries have leaked and damaged both the
microprocessor board and also the keyboard electronics circuit board
below. This was an ARP Quadra that actually didn't suffer from battery
leakage, so the boards are clean! To keep them clean, I've relocated the
batteries to a battery holder in the bottom of the chassis, a standard upgrade
I make to all Quadras that I refurbish.
This synthesizer looks in good shape for a 40+ year old
synth. There is a cosmetic ding on the
membrane panel (all membrane panel functions work), and a small bend in the
chassis under the keybed. Overall it
looks pretty sweet, particularly with the new upgrades! See the pictures
and judge for yourself--or better yet, come check it out in person and take it
for a test drive.
Prospective buyers are welcome to come try it out before
purchasing. Local pickup is welcome and encouraged. If being shipped, the
instrument will be professionally packed by the UPS store and insured for the
full purchase price, but this is a vintage electronic item, so all sales will
be as-is and final. But visit the Synthchaser youtube channel and rest
assured that a high quality detailed restoration was done to this synthesizer
by the expert on ARP Synthesizers.
If picking up locally and paying cash, not only will you
save on shipping, but I will also include an Anvil Fibre Case (which will need
new foam).
If the purchaser has this re-shipped out of the US, I take absolutely no responsibility for the state of it when it arrives to you. I only ship synthesizers within the US, and I only warrant that they arrive safely to their original shipping destination in the United States. If you are outside the US and you buy the synthesizer, you are buying it totally “as-is”, and shipping insurance will not cover it if it has been reshipped to another address.
