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Maximum input/output level

MctwinsMctwins Posts: 113

I need to know what the maximum input/output level is on the 260. Ive been reading my spec for the preamp and the maximum output is 16 Volts rms(26 dBu). Should I follow the meters on the 260 saying 22 dBu.

So, is the maximum voltage on 260 around 10 Volts(22 dBu).

If my thinking is correct I should reduce the input faders(not Master faders) by 4 dB.

Any Ideas



  • GadgetGadget Posts: 4,915
    Yes with the factory jumper setup you have +22 in and out, you can get 30+ but then the meters aren't calibrated...

    It is more important to have the gain structure set properly... and then use the input gain controls to get a strong signal (analog) at each channel for maximum signal to noise. If you do it your way you'll suffer in that department ...consider this... there is only one master set, but many input sets, so there is far greater potential for noise with great numbers of inputs.

    Take for instance a 24 channel board and typical mix, I might use all 24 channels, and if you add a little more noise with each of the 24 channels ...that's a LOT of noise. Now digital desks are a different situation...

  • MctwinsMctwins Posts: 113
    I belive that my Gain structure is as good as it gets with the gear I'm using. Everything is clipping at the same time(almost) I can do some more adjustments. The overall noise is acceptable.

    What do you mean about
    "and then use the input gain controls to get a strong signal"

    I asume you mean input controls on amps.

    So, this means that the headroom on 260 is +18 dBu at nominal level of +4 dBu.

    My preamp has 5 Volts on Main out at 100 % on the volume control feeding the 260.

  • GadgetGadget Posts: 4,915
    Ok, perhaps we should get a better idea of just what system were talking about here...is this the cinema system or the PRX... and what mixer...I get mixed up some times because I speak to so many different people...

    That comment is predicated on the live audio mixers where you might have 8-56 inputs...most mixers have a PFl button that you can push and it turns the master output meters into the channel strip meters... this way you can more accurately dial in the gain for each channel using the input gain control.

    In analog sound we want a big fat signal with headroom on each input for a high signal to noise, in digital (like with the Presonus studiolive) we need a decent signal with NO CHANCE of clipping.

    So if that wasn't your question, then you'll have to be more specific.

    Best regards
  • MctwinsMctwins Posts: 113

    It is the cinema system. The preamplifier is an Mcintosh C2300 with no input/output levels adjustments connected to 260.

    The spec is for the preamp as mentioned 16 Volts rms maximum.
    At 100 % volume I have on the output 5 Volts. I measured with an multimeter and the output is 5 Volts at 1000 Hz pink noise. 78 % I have 1.23 Volts (+4 dBu) and 70 % it is 0,775 Volts(0 dBu).

    Do I really need to adjust the mixer levels on the 260. For now it is all at zero. It seems to work OK. I just want to know if my pre has enough signal to drive the 260. As I see it it does.

    So the preamp can drive the 260 into clipping???
    If 260 has its maximum at 22 dBu(10 Volts) and preamp has 26 dBu(16 Volts).

    Ok I am not running the volume at 100 % :lol:

    So pre is higher than 260 witch is higher than the amps. The amps do clip at around 12-14 dBu. The input signal dont clip at this point.

    Amps are one Mcintosh MC252(in stereo) with sensitivity at 3,2 Volts(fixed). Crown MAI(in dual) is set at sensitivity 5,1 Volts(26 dB). If my thinking is correct the headroom of Mcintoch is 12 dBu and Crown 16 dBu. I have raised the input level of the Crowns by 3-4 dB. This is to match the output between the Crowns and Mcintosh. It seems to work in practice. The input signal is lower than the output of Crowns.

    I just want to share if my thinking is on the right way.

    I hope this info isn't to much for you, it is for me.

  • MctwinsMctwins Posts: 113

    I finally burned the "track 58". This pink noise is way much better than the one I got. Now I can run pink noise at 0 level on my pre. I did a quick check and when I turn the volume on the preamp to almost full I got the +22 dBu lights flashing. I will recheck everything to be on the safe side.

    Gadget, I will pay more attention in what you say :oops: . I should burned that track way earlier.

  • GadgetGadget Posts: 4,915

    Making more work for yourself are you? No problem on this end. Hey, question, Did I not ask if you were the one with the JBL cinema system? I looked back and you clearly have the McCintosh amps and JBL speakers...Was the other guys another model or something?

  • MctwinsMctwins Posts: 113
    It is me with the cinema and the PRX system.
    I dont know about the other guys.

    I am slowly starting to understand the whole gain structure issue. I will report back when I re checked the cinema system.

    It has been lots of dBu and Volts here and there in my mind recently. :lol:

  • DennisDennis Posts: 801
    Gadget wrote:
    Was the other guys another model or something?
    That guy had SR4700A series (rock n roll, not cinema).

  • GadgetGadget Posts: 4,915
    I think I'm loosin it...
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