Posts by charonme

    I have been testing this a couple of months ago and the usb midi loop hack seemed to work, but I wasn't able to reproduce it now.
    My hypothesis was that something related to the internal virus audio frequency (44.1kHz or 48kHz) had an effect on this problem and connecting it to a computer causes the virus to sync to the computer usb audio driver. But I was wrong, the usb midi loop doesn't help.

    I sometimes have this problem too, but I can't reproduce it very reliably under practical conditions. Sometimes it appears that changing the clock to 48kHz slightly helps, but other people trying this reported that it got worse for them.


    I also noticed the problem can go away when I connect the TI to a computer via USB (in a simple USB mode without the virus VST) and set up the computer to route MIDI coming from the TI midi in directly back into the TI synth. (I use a HW sequencer connected to the Virus directly with a din midi cable)

    I just found out the C uses MIDI CCs 97-100 for unison settings (like described in the C manual), however the TI ignores these and instead uses "bank D" sysex data 120-123 (positions in dump 504-507). One of the results of this is that transferring patches between Ti and C using the MIDI dump function can break the unison settings.

    By the way, the unison mode on the C goes up to 16 while on the Ti it only goes up to 8.

    I just found out the C uses MIDI CCs 97-100 for unison settings (like described in the C manual), however the TI ignores these and instead uses "bank D" data 120-123 (positions in dump 504-507). One of the results of this is that transferring patches between Ti and C using the MIDI dump function can break the unison settings.

    By the way, the unison mode on the C goes up to 16 while on the Ti it only goes up to 8.

    if the stereo signal you routed to the 1 input gets routed back to the other channel...they dont jump through air

    correct, the only thing the left input ring is connected is the normalizing/switch pin of the right input socket. The right input ring is not connected to anything


    In balanced that sleeve goes thru the "impedance balancing" to ground <- that is the circuitry you mentioned, which cancels the noise

    that would be a resistor between the ground and the ring on an output socket (my virus uses 470ohm resistors for this), but that's not the circuitry that cancels the noise. That circuitry would have to be connected to the inputs and it would have to subtract the ring input signal from the tip input signal usually using an opamp.


    Stereo is a different thing completely

    this is what I was pointing to. The left virus input is a stereo input rather than a balanced mono input

    and how about when the ring is not connected to anything?

    also what about stereo inputs? their rings are not connected to ground, but surely they can't be considered balanced, or can they?


    There is no need for that old school tip - ring - ground differential (where you have opposite polarity of the signal in the ring and tip) in order the signal to be "balanced" and (ground)noise canceled.

    Perhaps not, but the subtraction is still needed in the input circuitry for the noise to get cancelled

    how did you expect the one input to "process" the stereo signal?

    I expect a balanced mono input to subtract the ring signal from the tip signal to create the resulting mono signal. Instead the tip is treated as the left channel of a stereo signal and the ring as the right channel. If I'm wrong here, how then should an unbalanced input differ from a balanced one?

    if you present an active balanced input, does the Virus make use of it, or is it also limited to impedance balance.

    I just tried it and my TI2 desktop doesn't process the input as a balanced signal at all. The inputs on my TI2 are not actually balanced. Furthermore when a stereo signal is plugged into the left TI input the right channel from the stereo signal appears on the right TI input which would be impossible if the TI input was balanced

    Virus TI only has impedance balanced outputs...


    this seems a bit of a surprise for "high end" equipment... you would hope it would use an active balanced output, but perhaps Access will explain why this is not necessary? (in fairness, few synths provide balanced outputs)

    this is interesting because the CS42516 codec chip (the Virus uses for DACs) outputs active differential signals, but then the six differential output pairs are subtracted with NE5532 opamps and the resulting (unbalanced) signal is sent to the output jacks. There are even solder pads prepared for three additional dual opamps on the other side of the PCB, so I guess it would have been possible to make it output differential balanced signals


    I guess this still leaves a question , but I fear the answer... if you present an active balanced input, does the Virus make use of it, or is it also limited to impedance balance.

    I would expect a balanced input to just subtract the + and - signals so it shouldn't matter how are they balanced. The CS42516 does have two balanced analog inputs on chip (4 pins for two mono inputs). However I wasn't able to find any input (un)balancing on the PCBs. I couldn't even find what are the jack rings connected to. However I found that plugging a stereo cable into one of the inputs reroutes the ring signal to the second input

    When using a S&H poly LFO mod source or the RANDOM mod source to control filter cutoff each of the poly voices keep their own filter cutoff setting. Is something like this achievable if I want to send the value to virus from a sequencer together with each note?
    For example I'd send D#4 + value 64 for cutoff using some special CC (not the usual CC40 for cutoff) and then G#4 + value 127 for cutoff and the intended result would be D#4 playing with cutoff=64 and G#4 with cutoff=127