Would you like dual-SID stereo, triple-SID, or FM synthesis?

ARM2SID is a two- or three-SID and SFX Sound Expander (OPL FM) emulator in a single DIP-28 package. You can add the optional second socket for stereo adapters, or connect the signals directly to your Commodore computer.
- up to 12 audio channels (2× SID, 3× SID, FM, or SID + FM)
- compatible with all C64 and C128 boards (please read the manual)
- stereo with any combination of 6581 and 8580 models
- automatic fallback to dual mono if the second SID is not used
- configuration and firmware updates via software utility on the C64/C128

ARM2SID variants:

• ARM2SID with second SID socket and 5 cm cable
  For boards or stereo adapters with two SID sockets up to 20 mm apart. This is the best option for most stereo adapter solutions. SFX Sound Expander emulation is available only if the adapter or board supports DFxx addressing on the second socket (for example MixSID or Ultimate 64).
• ARM2SID with second SID socket and 10 cm cable
  Choose this version if the distance between your SID sockets is greater than 20 mm. If you need a longer cable, please contact us.
• ARM2SID with second socket for C64 Reloaded MK2
  A special version of the previous option with additional resistors that shift the external input offset so the C64 Reloaded MK2 can automatically detect ARM2SID as an 8580. This is the recommended option for the C64 Reloaded MK2.
  Note: the input resistors may slightly influence the ExtIn signal if it is used.
• ARM2SID without second socket, with 30 cm connector cable
  (+ 2× Schottky diodes and pull-up resistor)
  This is the most flexible option for plain C64, enabling:
  - dual SID stereo
  - triple SID
  - SFX Sound Expander
  - SID + FM
  The wires must be connected directly to the computer. This is not difficult, but basic soldering experience is recommended.
• ARM2SID with second SID socket and dedicated cable for Commodore 64 Ultimate or Gideon's Ultimate 64 (Elite, Elite II)
  The best option for Commodore C64 Ultimate or Gideon's Ultimate 64.
  It is based on the standard 5 cm interconnect cable, but the A8 address line is rerouted: instead of going directly between the two SID sockets, it is extended and finished with a Dupont connector for the SID A[5–9] header on the Ultimate 64. The second SID2 socket is included.
  This version allows:
  - dual SID stereo
  - triple SID
  - SFX Sound Expander (FM)
  Each mode requires a slightly different configuration in the Ultimate config and ARM2SID software.

Note: A stereo expansion board is not included. The 5 cm and 10 cm cable versions are intended for systems that already have two SID sockets. The 30 cm cable version connects directly to the computer and does not require a stereo adapter.

Note: The optional second SID socket (SID2) does not have the ExtIn signal connected, so audio input is not available on the second SID. If you need ExtIn on both SIDs, please use two ARMSID modules.

Which version should I choose?

• Standard C64 with a stereo adapter → 5 cm cable version
• Commodore 64 Ultimate / Gideon's Ultimate 64 → C64 Ultimate cable version
• Standard C64 without a stereo adapter → 30 cm cable version (requires basic soldering)