ROM expansion turns Roland TR-707 into an 808 and more

HKA Roland 727 PCB

HKA Design has announced a ROM expansion that lets you add on the sounds of the iconic TR-808, TR-909, LinnDrum, Linn LM-1, and Oberheim DMX. The expansion gives you a total of eight sound banks, including the stock sounds of both the TR-707 and TR-727. Switching between banks is performed by holding down one of the first 8 step keys while turning the machine on.

Aside from the new sounds, HKA Design said that the modified TR-707 or 727 should behave just like a stock unit – with no loss in function. As such, it should also be compatible with other modifications or circuit bends you may have previously added. Check out what you can expect after the modification below:

The kit does require a fair bit of soldering but comes with instructions on how to install the expansion without wrecking your precious vintage unit. The full kit consists of a pre-assembled PCB, a ribbon cable, and a DIP socket.

HKA Design also shared a detailed write-up on his process of porting the sounds from the TR-808, TR-909 LinnDrum, LM-1, and DMX over to the 707 and 727. You can read it here.

The expansion kit is available at $60 through


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Director and DJ, Ian French (Naif) is passionate about every genre of music from Breakbeat, to Drum & Bass, to Techno and House. A man that lives in a world of beats and bass, and total confusion about life!