This ROM Expansion Kit Turns The Roland TR-707 Drum Machine Into A 808, 909, LinnDrum…

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Harry Axten has developed a new ROM expansion for the Roland TR-707 with which the legendary drum machine gets sounds from the 808, 909, LinnDrum and others

Vintage drum machines are gems, but you shouldn’t buy them for display. They don’t belong in a private museum, but rather well cared for and played. Although the sounds of these are legendary to this day, there is more power in the device than just these rather basic best-known sounds. The English developer Harry Axten opened his beloved Roland TR-707 drum machine and removed the heart of the machine, ROM chip. However, he did not replace it with a matching (1 to 1 clone) but developed a new ROM chip.

The new chip is called Roland TR-707 ROM Expansion and brings new life to the legendary drum machine. It’s a third-party mod that expands the sounds available in the original device.  It gives the machine 8 banks of sounds you can select, including the stock sounds from both the TR-707 and TR-727, so you can turn one into the other.

Roland TR-707 Expansion Kit

The 8 banks feature sounds from iconic drum machines: TR-707, TR-727, TR-808, LinnDrum, LM-1, DMX & TR-707 + TR-727 mix (handy for those who don’t own both machines). Changing between 8 banks is done by holding down one of the first 8 steps while turning the machine on. The setting is remembered and will be recalled the next time it’s turned on. There are no modifications to the outside of the machine, and the installation is easily reversible.

Apart from having different sounds, a modified TR-707 / TR-727 behaves exactly the same as a stock unit, no functions are lost. The machine should also be compatible with any other modifications or circuit bends you may have fitted, such as voice tuning, hi-hat decay mods etc. The ROM expansion kit will switch out all of the sounds (referred to as a bank) apart from the last two sounds (crash + ride / quijada + chime), which will remain the same across banks, as they are stored on their own ROMs in a different part of the machine.


  • Adds eight sound banks to the TR-707 or TR-727 (see page for full list)
  • Original sound sets from both machines included, so the modified machine can work exactly as stock
  • ROM bank is selected by holding down one of the first eight step switches at startup
  • Reversible, invisible installation – doesn’t require any holes drilled, track cuts, etc.
  • Kit includes pre-assembled expansion board, chip socket and ribbon cable

Roland TR-707 ROM Expansion is available now for £60. The next batch is expected in later September.

More information here: Harry Axten

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