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Mesa Subway DI + poweramp

Discussion in 'Amps and Cabs [BG]' started by Red Planet, Apr 13, 2018.


  1. Red Planet

    Red Planet Inactive

    May 29, 2005
    Atlanta
    I'm cranky in my old age.
    Anyone running this combination as their rig?

    Would like to hear about it. How you connect? Works OK? Pummels?
    What amp and cabs?

    I have the DI and thinking of getting a bigger amp that can run four 8 ohm cabs for an outside rig.
     
    Last edited: Apr 13, 2018
    Stumbo and BadExample like this.
  2. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    That was my wet dream before getting hold of some GB streamliners.
     
    hennessybass likes this.
  3. bucephylus

    bucephylus Supporting Member

    Aug 18, 2002
    I am primarily using the Subway Preamp for ampless gigs. But, I also have a Crest ProLite 3.0 in a rack, which most effectively drives a pair of Bergantino 4 ohm cabs for big backline gigs.

    You are on solid ground with your concept.
     
    Red Planet likes this.
  4. 57pbass

    57pbass Supporting Member

    Aug 1, 2004
    Bayside, New York
    I’m using one with my powered Bag End cabs. Pretty straight forward.. sounds amazing..
    I wish it had a mute switch..
     
  5. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    If you are using a tuner with a mute footswitch into the input, you can achieve the same thing this way.
     
    Stumbo and 57pbass like this.
  6. Stumbo

    Stumbo Guest

    Feb 11, 2008
    Kill switch on your bass can do it too.
     
    agedhorse and 57pbass like this.
  7. xroads

    xroads

    Nov 6, 2012
    I run a combination of the Mesa DI into an EV Q44-II power amp. Works great. The Preamp has enough
    power to drive the power amp. Great powerful clear Mesa sound.
    There is only one minor issue with the Mesa DI: it has a constant, low level signal at 20KHz. One cannot really
    hear it through the Cabs or in the PA, however the signal meter shows this, which is kind of annoying.
     
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Let me address this. This is a very low level (about -55dB) ~22kHz signal which is the residual carrier frequency of the charge pump in the power supply. The only reason why it can be seen on some metering is because the metering range is extended on some mixer models (to as low as -80dB now) which shows all kinds of audible and inaudible noises. Some metering algorithms also scales the high frequency so that it is over-represented.

    It is completely inaudible under the most demanding listening conditions, and poses no real world issues.

    For comparison, the most extended metering on the highest dollar classic studio consoles was only 40dB so this would never have been seen. Only since the introduction of the newer digital consoles with extended metering have these buried carrier residuals been noticed. Lots of pedals have this.

    This is identical to the PWM carrier residuals seen on every single class D amp on the market, but it doesn't show up on meters even though it's MUCH higher level because the typical spectrum is out of band and there's no extended metering range on the output.
     
    BasturdBlaster likes this.
  9. bucephylus

    bucephylus Supporting Member

    Aug 18, 2002
    FWIW, we were seeing the same thing on our Behringer X board in the rehearsal space a couple months back. After a LOT of cable swapping, we finally traced it back to a bad ground on one of the AC receptacles. Since then, I have been powering from a different receptacle and not seeing it at all. I suppose with all the wireless etc etc happening these days, the ground circuits have become that much more critical.

    Not saying this is what you are seeing; just mentioning because it was a similar thing.
     
  10. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    An earth ground somewhere (at the XLR outs, 1/4" out) goes a long way towards minimizing this. Without an earth ground, the level of the switching residual may indeed be a little higher.
     
  11. xroads

    xroads

    Nov 6, 2012

    Thanks for your reply, I had assumed it is something like this.
    Attached a snapshot from my recording setup. Subway DI directly into the interface, to garageband, no compression.
    Levels/Gains are set normal for a passive Preci to give a clear and undistorted sound at around -10dB on the left scale. Note the peak at
    20kHz. It is not audible, but on a level that is not really negligible either.

    thumbnail.jpeg
     
  12. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Looks like -45dB but relative to 0dB rather than -10dB that you are using, that ends up at about -55dB.

    That's way down, if you had been using an SSL or Neve console, the residual would fall well below the range of the metering and would be invisible.
     
    xroads and BasturdBlaster like this.
  13. LUpton

    LUpton Supporting Member

    Oct 22, 2012
    Tampa, FL
    Probably too old for this sh--
    LPF in the DAW software EQ to get rid of it. Nothing usable for a bass (in the context of a mix, IMHO, etc...) up that high anyway...
     
    agedhorse likes this.
  14. xroads

    xroads

    Nov 6, 2012
    Agreed, that is not a problem, however if I send this signal to the FOH mixer, they see a constant signal in their meters, and some have complained.
     
  15. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    If they weren't looking at -50dB and if their metering algorithm would scale the energy in that last octave based on average energy rather than peak energy, and would ignore out of band signal, they wouldn't have anything to complain about!

    By comparison, this amount of signal accounts for a few milliwatts of power on a typical larger PA. (If you convert -55dBu to power)
     
  16. Chef

    Chef Moderator Staff Member Supporting Member

    May 23, 2004
    Columbia MO
    Staff Reviewer; Bass Gear Magazine
    I know this doesn't directly answer your question, but:
    The Mesa D800/+ will drive 4 8 ohm cabs, and be smaller, lighter, and more easily portable than a racked rig.

    Otherwise, carry on. Decent idea.
     
    jedicollector and georgiagoodie like this.
  17. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Feb 27, 2021

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