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Running The Grace Designs Felix to Two Powered Speakers

Discussion in 'Amps, Mics & Pickups [DB]' started by Ric Vice, Feb 17, 2019.

  1. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
    So, I have a Grace Designs Felix with one 1/4 amp out. I own two MAS powered speakers a 1/8 and a 4/5.5 on occasion I'd like to run them both together, what magic boxes are out there to do that.
    Ideally on a really big outdoor stage, I'd like to use the 1/8 as a moniton and the 4x5.5 as a "main". All ideas will be appreciated, except buying another Grace. :smug:
  2. Can a line out drive a powered amp? And you would still have a line out left, right?
    Last edited: Feb 17, 2019
  3. wathaet


    May 27, 2007
    Something transformer isolated would be my preference.
    The Radial LX3 will do the job nicely. You do not want to create a ground issue between two amps and the Grace.
  4. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
    Could possibly work, the hanger is there are independent two DI’s out, designed to be individual sends FOH. They are tied to the independent channel volume controls. So it would impact the FOH volume. The amp out has it’s own separate volume, independent of the channel volumes.
  5. rickwolff

    rickwolff CGJ Emeritus (Certified Gear Junkie) Retired??? Supporting Member

    Seanto likes this.
  6. wathaet


    May 27, 2007
  7. Maple

    Maple Supporting Member

    Feb 25, 2016
    San Francisco Bay Area
    Do both powered MAS units have an output for an extension speaker?

    If so and IF it’s ok to have an unpowered ICE unit driven by another power source (I have been curious but haven’t researched it), then you might be able to connect one to the other

    But I think a splitter to each input would be fine. The inputs are isolated.
    Ric Vice likes this.
  8. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
    Yes they do, I've definitely done that, Mike puts a speaker connector on his powered versions to allow for an extension. It sounds great that way, but I'd like to try using the power amps in both

    the MAS 1/8 and the MAS 4x5.5.
  9. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
  10. Zbysek


    Mar 23, 2017
    Czech Republic
    I didn't know that.

    The only (imperfect) solution which comes to my mind is to run the second cab from tuner output of your Felix...
    Last edited: Feb 19, 2019
    Povl Carstensen likes this.
  11. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
    Interesting, I'll see how that would work, have to check to see how much gain the Tuner Out provides.
    Zbysek likes this.
  12. Chris Symer

    Chris Symer

    Dec 13, 2009
    I know it means that you wouldn’t have independent volume control on one side ( unless you put a volume peddle there) but otherwise I don’t understand why you don’t want to use one of the direct outputs for one of the speakers (perhaps the 8?) and the amp outfor the other one.
    Remyd and Povl Carstensen like this.
  13. shwashwa


    Aug 30, 2003
    this is speculation, but since the speakers are so different I'm guessing he might want separate volume control for each.
    In which case, I would use a splitter and then something like a graphic EQ pedal that has a volume slider on it for one of signal paths,
    Ric Vice likes this.
  14. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
    Chris the Direct outs are 3 pin cannon so you would have an impedance mismatch and the powered in’s on the MAS speakers are 1/4” phone plugs so I’ll have to see if that will actually work. Thanks
  15. Whether an output is xlr or jack does not say anything about its impedance. I assume that the output of the cab is at line level, as is its input, thus connectong both should not pose a problem.
    DoubleMIDI likes this.
  16. DI XLR outputs can be at mic or line level. My Genz Benz Shuttle 3.0 has a switch for the DI XLR out.
    I'm pretty sure hat the impedance for both is the same, low (like a microphone). A low output impedance means that a large current can be delivered before the signal breaks down (at an ever lower following input impedance). So if the input impedance of the following device is higher that means, that the current flow is lower which doesn't influence the signal.
    Since a line level signal has a higher impedance than a mic signal (and a higher voltage), the impedance is not the problem unless you go from a line out to a mic in (but then you overload the mic input with the much higher voltage).
    It would be a good idea to check impedance and sensitivity (voltage levels) of input and output, but only an input impedance of the receiving device that is lower than the output impedance of the sending device might lead to problems, not the other way.

    In case of passive piezos as a sending device we have a special case because the piezo crystal not only acts as a voltage source, but also function like having a built-in capacitor in series and also has built-in resonators at it's eigenfrequencies. In this special case the load (inverse input impedance) influences the resonating qualities of the crystal (as well as mechanical pressure) which is a more special case than connecting two active (amplifying) circuits.
    To be fair I need to mention that even two active circuits that are connected have an influence on each other, but they are usually designed to keep that influence small, specially if they can get connected to other devices in various ways.

    'Matching' impedances is never a good thing (at least for audio amplification), because if you have the same impedance for output of the first device and input of the second device the resistors used to define the impedance build a voltage divider, so only half of the signal voltage reaches the next devices input. If the input impedance is nine times the output impedance, 90% of the voltage level reaches the input.
    In case of ten times it is 10/(10+1)~0.91 which is approximately 91%. In case of twice the input impedance it is about 66.7%, three times the input impedance 75%.
    You never reach 100% unless you remove the output resistor, but then the output cannot be short-circuit-protected, so for outputs there is always a resistor in use, the value depends on the current that could be delivered from the last internal amplification stage and from the impedance needed for the application.
    So the input impedance is almost always several times higher than the output impedance and I would not call that 'matching' because most people would think that 'matching' means the same value on both sides.

    An electrical engineer might correct me here or there (I'm an amateur in EE), but as far as I understood the stuff it is basically correct.

    If you want it shorter with less explanation read the last message from Vunz.
    Vunz and s0707 like this.

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