This small chiclet PCB solves an annoying issue with certain ARP 2600’s. The problem is that some, if not most 2600’s have difficulty triggering the ADSR with a 5V gate coming from most modern sequencers or controller keyboards. Even if it will trigger, often the 2600’s ADSR and AR wont trigger correctly, resulting in short decay and release times and almost no attack time. Yes, using the pre-amp can be fudged to work, but its also inconsistent.
This mod is totally non destructive, and wont limit you to only using 5V gates. With our chiclets transistor design, all it is doing is converting positive voltages to the full rail voltage of the 2600 (15V). Since it’s not amplifying the incoming gate, there is no chance to hurt your 2600 with this chiclet. Any positive gate you throw at it will be turned into 15V, simple as that! So, no need to worry about the keyboard gate from your stock arp keyboard, or any old sequencer that already work brilliantly, they will still work just fine!
Connection is simple and non destructive. A small chiclet is installed and only needs 4 simple connections. No trace cutting required.
To check if your 2600 needs this modification, create a patch with the S&H Gate triggering the ADSR. Insert a patch cord into the S&H gate jack (near the AR) and connect that cord to any modern sequencer. If your 2600 won’t trigger, or the ADSR isn’t triggering identically to the internal clock, then you need this chiclet.
Note: This is only for vintage 2600’s.