![]() ![]() Here is a binary image of the OS EPROM from my two units. I read out the sysex data and wrote it to a file using a program called MIDI-OX. ![]() Here is a list that shows the program numbers for the (almost) B version. I did not have the programming parameters for those, so I placed the sounds that were in A, but not in B in those spots instead. There are some sounds in the factory B version that do not exist in A. (Thanks) I created the B version by manually copying each program from their A location to their B location. Here is a zip archive that contains MIDI sysex files for both A and B versions (almost) of the Multi-Trak Factory Programs. Other Misc Multi-Trak Related Information: Here is how the mod looks with the extra socket and the little pc bd in place: (the green wires are an SCI factory mod that many units have) I attached this board to the top of the Z80 with double-stick foam. I made a small pc bd that holds the two diodes and resistor for a neater job. To OR the two signals into one, I use two schottky diodes and a 1K pullup resistor. Both of these signals come from the Combo chip. The other one connects to an OR of the original EPROM chip select and the spare decoded chip select. One of the bent-out pins connects to A15 at the Z80. The easiest way to do this is to use a second IC socket, with two pins bent out, plugged into the SCI IC socket for the EPROM. To perform the mod, you need to replace the 27128 with a 27C256 EPROM, and connect two pins on that EPROM to points in the circuit that do not route to the EPROM socket. The Multi-Trak makes it even easier, as the third decoded chip select from the combo chip is unused and available. Since both the Max and the Multi-Trak used a 27128, which is almost exactly the same pinout as a 27C256, doubling the amount of available code space is not difficult. When the Multi-Trak power is cycled, this parameter is reset to 0 (SCI scale factor). There are 5 settings for this:ġ6-31: Osc env has 2X the effect of the SCI codeģ2-47: Osc env has 4X the effect of the SCI codeĤ8-63: Osc env has 8X the effect of the SCI codeĦ4-79: Osc env has 16X the effect of the SCI codeĨ0-127: Mapped in the code to a value of 64. He wanted a way to increase the effect of the oscillator envelope. The Osc Env Scale Set CC was added at the request of Ryan (AKA plutoniq9). ![]() The Six-Track does not have these, so I assigned them myself: Supports CC control of the following parameters: (The CC codes were chosen to match the Six-Track so that existing control software could be used) I now have a new version of the code, which I am calling V2.3, that has the following features: This has been very useful for learning how the code works, what RAM locations store what values, etc. Basically anything I want to see anywhere in the synth, including inside the combo chip or the Z80. I can see the pitch, VCA setting, VCF setting, etc of each voice. I created a Verilog simulation of the Multi-Trak which allows me to press (virtual) keys or switches, receive MIDI messages, etc, and watch how the code reacts. I also wanted to put the factory patches in the EPROM, so they could be restored easily if lost. Since I had some familiarity with similar code in the SCI Max from another project, I decided to see if I could add this feature to the Multi-Trak. ![]() This seems a little odd, since the Six Track and the Max both have this feature, but possibly SCI at the time didn’t feel it would get much use, or maybe they just didn’t have room in the EPROM for the code. Last year it was brought to my attention that the Multi-Trak didn’t support CC parameter changes over MIDI. ::: Sequential Circuits/SCI Multi-Trak Page The Sequential Circuits Multi-Trak is a (velocity sensitive) 61 key, 6 voice multitimbral analog synthesizer, featuring a programmable oscillator, resonant low pass filter (24dB CEM), 3 envelopes, and LFO, along with 100 program memories, arpeggiator, 4 track (1600 note) sequencer, stereo chorus, individual outputs, and MIDI.I’m so excited i quoted the whole page from the Tauntek site! The same site that posted the SCI MAX upgrade i documented here: Sequential_Circuits Multi-Trak Multi-Trak (image courtesy of SoundDoctorin)Īrchitecture Class: Conventional (subtractive). ![]()
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