Balanced Outputs ? (TI Key v 1)

  • Hi,


    So Ive got a TI 1 keyboard... and my understanding was that it has balanced output...
    but despite using TRS cables, the output does not appear to be be balanced.


    as a test I did the following :


    a) connect Out 1 L to a splitter cable
    b) connect the L and R of the splitter cable to different channels on my mixer
    c) play a note.


    what I expect is to see a signal on both channel on the mixer...
    obviously inversions... such that
    if I sum both channels I would get silence
    if I play either channel I should hear sound


    BUT what I find, is I'm only getting a signal on one channel...
    i.e. this is an unbalanced signal


    I've tried all 6 outputs out , and they are all the same


    Ive tried the same test with my audio interface (which supports balanced outputs) and the mixer and it works as expected...


    so was I incorrect... does the TI mk 1 not have balanced outputs, or only the TI 2?
    or is there some way I need to 'activate' it.... (which would seem odd)...
    has anyone else got this working correctly?


    thanks for your help/insight


    Mark

  • I think I asked a similar question here not so long ago. These were the specs I believed the MK1 to be (below) but i'm not so sure as selecting +4dB on my apollo input makes the TI very quiet with balance cables compared to +10dB and the USB output.


    Studio Grade Converters192 Khz studio grade D/A converters (+4dB balanced output), with soft limiting algorithm. 24 bit A/D converters. The Virus produces one of the hottest signals in the industry. Live keyboards can leave their DI boxes at home and plug the symmetrical outputs right into the stage box (special cable required).

  • yeah, indeed the internet archive shows the TI 1 :

    Quote

    Inside, a new Dual-DSP core delivers stellar performance with super-low latency. TI also employs studio-grade converters with 192 Khz/24-bit D/A. These are paired with +4 dB balanced inputs and outputs and a switchable ‹‹soft limiting›› algorithm, and accompanied by S/PDIF digital stereo output and input as well. The onboard USB port is compatible with USB 2 specifications and works with USB and Hi-Speed USB devices and peripherals. For easy access to all these new jacks, the entire I/O panel of the TI desktop model can be rotated 90 degrees so the interface is on the rear panel. The 4U Rack mounting kit is also included with the desktop model.


    hmm, so the TI mk1 is supposed to have balanced outputs...


    Aj  
    if you plug your headphones into the LEFT output only, do you hear something in both sides? ... I'm pretty sure you should if its balanced... but only on one side if its unbalanced.


    @Marc ... am I missing something? is there a fault on my TI?

  • ok, so I think the the answer is :


    the Virus TI only has impedance balanced outputs...
    (see http://www.soundonsound.com/so…articles/qanda-1013-4.htm for an explanation)


    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)


    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.

  • Yep, just checked only the one channel with headphones as per EvilGus above. Always thought there was something strange going on but have only recently (always!) questioned it but have investigated it further recently having taken things a little more seriously :)


    Indeed it would be the only balanced synth I own, even my Prophet 12 (I guess high end) has unbalanced outputs. Never the less, the TI was marketed differently as we have discovered and if I dig out the original supplied printed manual I'm pretty sure this is what has been printed in the specs too, although has possibly disappeared from the online pdf version. Conspiracy theories! :D


    An official answer would be nice as I'll switch the input on my interface to +10, however I've found the levels with that to be a bit too hot in most cases compared to the USB output.


    Oh man, I need a beer :P

  • Here's your official answer: the Virus TI has balanced outputs. The type of balancing used is called impedance balancing as explained in the SOS article found by the OP.
    @EvilGuy: Ever considered that LEFT is the headphone output on the Snow whereas there's a separate one on the rest of the line. That's why you see a difference in volume.

  • Hi

    Here's your official answer: the Virus TI has balanced outputs. The type of balancing used is called impedance balancing as explained in the SOS article found by the OP.
    @EvilGuy: Ever considered that LEFT is the headphone output on the Snow whereas there's a separate one on the rest of the line. That's why you see a difference in volume.


    Hi Marc,


    So with "impedance balanced" outs to a DB25 input on an A/D converter (my audio interface), what cable do I need to use? For example, there is


    (a) DB-25 to balanced 1/4 inch


    (b) DB-25 to unbalanced 1/4 inch (single conductor cable)


    (c) DB-25 to unbalanced 1/4 inch (two conductor cable)


    any advice?

  • 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

  • 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

  • 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

    Eh? Maybe the Corona (not the beer) isolation has melted my head somehow, but..I have no clue what-so-ever how did you expect the one input to "process" the stereo signal?

    ..or is here some confusion with differential and balanced signals? They are two different things..

    Here is some reading for everyone https://www.hairballaudio.com/…balanced-and-differential

  • 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?

  • 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?In

    In unbalanced signal the ring connected directly to ground. In balanced it is not, both ring and tip are equal in impedance towards ground. The ring is connected to a sort of "virtual ground" if you wish. 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.

  • 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

  • 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?


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

    Stereo is a different thing completely (connector wise anyway), it has left signal (tip) and right signal (ring). and sleeve(or shield), which is grounded. If the system is unbalanced. In balanced that sleeve goes thru the "impedance balancing" to ground <- that is the circuitry you mentioned, which cancels the noise. It is 0V, but not the same as chassis "ground"