Author: synthchaser

I ripped the membrane panel off my ARP Quadra and then THIS happened…

Finally! A replacement for the legendarily flaky ARP Quadra membrane panel! Many an otherwise good Quadra have been turned into doorstops or scrap metal due to failed or damaged membrane panels.

In this video I briefly introduce two new goodies for the ARP Quadra. One is a replacement membrane panel, and the other is a set of LED illuminated sliders.

Both of these products, and the ARP Quadra shown in the video are available below:

ARP Quadra Replacement Membrane Panel

Synthchaser Precision LED Slider Upgrade Kit for ARP Quadra

Ex-Jefferson Starship ARP Quadra Synthesizer Serviced w/LED Sliders & New Membrane Panel

In this video we repair a broken sample and hold feature on one of the most iconic vintage synthesizers ever–the ARP 2600!

It was a huge honor and incredibly fun to work on the ARP 2600s from Don Lewis’ LEO (Live Electronic Orchestra) with him this weekend. LEO was a groundbreaking historic synthesizer that served as an inspiration for MIDI, having vintage synths from many different manufacturers (ARP, Oberheim, Roland, etc) all connected and working together. In this video, Don talks a bit about LEO, we show the problem with one of the oscillators in the ARP 2600, and then we troubleshoot and repair it.

There’s a new documentary, The Ballad of Don Lewis, which is available for pre-order on Amazon or On Demand from your cable provider that tells Don’s amazing story, which goes much deeper than just LEO. LEO will be on display again the the NAMM Museum of Making Music in Carlsbad, California starting in 2021.

The Ballad Of Don Lewis DVD:

https://www.amazon.com/Ballad-Don-Lewis-Various/dp/B083VPRQRT/

In this video, I explain how polyphony is achieved on the ARP Omni 1, Omni 2, and Quadra synthesizers using a master oscillator, top octave divider and frequency dividers. I discuss how this type of polyphony is different from the type of polyphony on the type of synthesizers with fixed number of voices, like the Prophet 5, Oberheim OB-X, and Memorymoog.

I also introduce 3 of my new retrofits–a drop in replacement for the Master Oscillator, a replacement for the TDA0470/TDA0470D gating IC chips, and a replacement 4075 voltage controlled filter.

00:00 Polyphony discussion
03:40 Master Oscillator replacement
09:10 TDA0470SC
10:06 4075 VCF Replacement

The pushbutton switches on the ARP Omni 1 synthesizer suck. The mechanical latch often breaks, leaving us unable to turn on sections of the synth. Other times, we need to press the switch at just the right angle to be able to get it to latch. And yet other times, the switch contacts get dirty and the switch gets stuck off or stuck on.

The originals have been obsolete for decades and are unobtainable. So I’ve created a drop-in replacement switch, that fits the old switch cap! Check it out!

ARP Omni 1 Replacement Switch

Functional demonstration of the ARP Axxe 37 key monophonic analog synthesizer keyboard. Also discussion of what went into restoring it.

ARP Axxe Analog Synthesizer Keyboard Fully Serviced w/ LED Sliders & new Walnut Panels

It’s time to dig into my stash of ARP Quadras and get a couple of them overhauled and back out into the world. This Quadra was looking really sad, all of its slider shafts were sheared off, and it was shipped to me partially disassembled and in disarray. But the seller said it was working… NOT!

In this video I share (just some of) the ordeal it took to get this Quadra awesome again. Including refurbishing sliders, replacing broken slider shafts, repairing battery corrosion, replacing a dead CPU chip, dead oscillator, dead bass section, no output, broken phase shifter, and the list goes on.

This ARP Quadra is now for sale below.

Restored Vintage ARP Quadra Synthesizer Keyboard