Modular synths straight into SQ-5

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This topic contains 23 replies, has 4 voices, and was last updated by Profile photo of whatsoup whatsoup 1 month, 3 weeks ago.

Viewing 15 posts - 1 through 15 (of 24 total)
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  • #86940
    Profile photo of whatsoup
    whatsoup
    Participant

    Does anyone know if it’s safe to run modular level outputs straight into the SQ-5, if the channels are padded? Thanks 🙂

    #86942
    Profile photo of KeithJ A&H
    KeithJ A&H
    Moderator

    Hey @whatsoup,

    Voltages on modular equipment can exceed the rating for the SQ inputs.
    So whilst it is close (max SQ input = +30dBu = approx 10V peak to peak = majority of modular audio signals) we would not recommend it, and it’s the reason there are dedicated eurorack to line level and mixer modules.

    Cheers!
    Keith.

    #86944
    Profile photo of whatsoup
    whatsoup
    Participant

    Thank you very much Keith for the quick response! I definitely won’t be chancing that one! Cheers 🙂

    #90386
    Profile photo of moebius
    moebius
    Participant

    Necromancing this question….

    I´m currently deciding between getting a second in-the-box mixer for Eurorack or use an SQ-5 for it´s obvious benefits. Still running a mixed setup, so I need to integrate line level from synths with Eurorack and vice versa. Ideally, I would be able to treat modules and synths as equal and have things routed back and forth via the SQ.

    As I´m not a big fan of wasting half of the modular rack for IO modules (8-16 channels in and out to Eurorack), what are the options here?

    A separate skiff for IO, holding just the conversion modules is one (costly) idea, but could grow incrementally as needed. What are the other options? Best practices?

    #90427
    Profile photo of whatsoup
    whatsoup
    Participant

    At first I took Keith’s advice, then I realised it’s just INSANELY expensive to start mixing stuff in eurorack, and even then you’re lucky if it’s even half as functional as something like an SQ-5, so I started going into it ‘for now’. Everything seems fine. My padded SQ channels normally default to 8 gain, but i find myself putting the modular channels at -6 (obviously your mileage will vary), I’m also putting a the SQ compressors on max to be on the safe side.

    I think the main concern is don’t blow your speakers? I have several failsafes in place, but you never know. Just be careful. Seems good to me, if I don’t forget to keep stuff turned down.

    #90428
    Profile photo of volounteer
    volounteer
    Participant

    @whatsoup

    the way I read Keith’s answer was you could damage the SQ if the input voltage is too high

    speakers are another issue. i wish someone could tell me why so many folks think louder is better.

    #90549
    Profile photo of moebius
    moebius
    Participant

    I´m more concerned about routing signals back and forth between eurorack modular, traditional synths, outboard effects and DAW. In my case, it is studio only, so I don´t care about clipping too much. I just don´t want to fry the SQ-5 with an occasional unexpected voltage spike. Given that IO modules in Eurorack are not cheap, mono or stereo only and eat precious hp, isn´t there something like a transparent 8 or 16 ch limiter that I can just put in the rack below the SQ? I´m not an EE, so please be patient if my question is stupid.

    #90551
    Profile photo of volounteer
    volounteer
    Participant

    @moebius

    if it is in studio why clip ever?
    why risk frying the SQ ??

    you can raise the final in the DAW as much as you want.

    why do so many people think louder is better ?

    #90553
    Profile photo of moebius
    moebius
    Participant

    Oh, I don´t. Once in DAW, I can happily pump things up.

    My main concern is that modular may spit out a voltage that may _damage_ the SQ.

    Example: Traditional patch, VCO to VCF to VCA. That filter will take away a lot of signal and should work without issues. But patching a signal from SQ Aux to some obscure modular FX unit may return something not as tame. Or let´s assume there is a filter somehow going into wild self-oscillation and straight back to the SQ. Worst case, you accidentally fat finger a patch in modular and send CV at full level to an SQ in. That´s where a constant +10V may arrive at the SQ until you find the right plug to pull. I´m just not sure if the SQ will handle that like a gentleman or throw some magic smoke at me.

    Adding a few numbers to the discussion (kudos to 2thick4uni):

    “While modular audio is typically 10v p-p, it can go as high as about 20v p-p.

    -10 dBv (consumer line level) = 0.895v p-p
    +4 dBu (pro line level) = 3.473v p-p
    normal modular audio level = 10v p-p
    peak modular audio level = 20v p-p

    -10 dBv = -7.78 dBu
    10v p-p = +13.2 dBu
    20v p-p = +19.2 dBu”

    #90786
    Profile photo of whatsoup
    whatsoup
    Participant

    I’m wondering, can you actually fry something with the voltage? I thought it was just loudness I had to worry about

    #90792
    Profile photo of volounteer
    volounteer
    Participant

    @whatsoup

    like KeithJ AH said: YES you can ‘fry’ the SQ circuit components

    louder is not better
    dial it all back a ways from the 11+ you want to use

    #90795
    Profile photo of whatsoup
    whatsoup
    Participant

    @volounteer No one said we want it loud, or what gains we want to use, that’s your assumption – I just want it to be safe. If simply turning the gain down is enough to not fry the circuit then that is good enough for me.

    #90796
    Profile photo of volounteer
    volounteer
    Participant

    @whatsoup

    more gain == louder

    louder == more gain

    turn it down so the voltage could never get high enough to cause damage

    if you are worried put a dummy load on the output and measure the voltage levels
    then tape the knobs so they cant get moved to the right.

    #90797
    Profile photo of moebius
    moebius
    Participant

    volounteer,

    I think there is a misunderstanding. Our concern regarding damage to the SQ circuits is not there because we´re trying to feed it as hot as possible, gaining maximum loudness or whatever.

    The reason is that a modular synth sometimes delivers unexpected results and may suddenly put out a much higher voltage than during normal use, see my examples above. You _may_ accidentally patch a constant voltage into the audio path. The operator _may_ have wanted to patch a CV signal to a CV in, but somehow ended up at the wrong audio path. A filter may go berserk by some unplanned modulation and so on.

    The high levels are not created _on purpose_, they just may occur by user error. Under normal circumstances the signal will be tamed by VCA, VCF, mixers etc and be similar to any strong synth signal. It will stay at reasonable levels that the SQ can handle. Much like your average -10/+4 synth.

    #90800
    Profile photo of volounteer
    volounteer
    Participant

    @moebius

    then maybe you need to build a simple protective circuit so that any high unexpected voltage is clamped to a maximum safe level

    and throw in a low pass filter to slow the higher freqs in the spikes to ensure the following zener or whatever works without problems

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