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Using Ampeg SVX onstage

Discussion in 'Amps and Cabs [BG]' started by bluesdogblues, Sep 6, 2008.


  1. bluesdogblues

    bluesdogblues

    Nov 13, 2007
    Hi,..I'm a session bassplayer (usually) for Rap, R&B and Pop/Rock artists.

    I'm planning to use Ampeg SVX onstage with MacBook and Digidesign MBox Mini (Fender P bass -> MBox's Mini Left Output to Stage Bass Amp & Cabinet strictly for monitoring purpose only & Right Output to PA)

    My Questions are:

    1. Since the Output of The MBox are 1/4 Balanced Jacks, do i still need a Direct Box for my output to PA or can I just go straight from the MBox (Right) Output to the PA? if i can go straight, should I use 1/4 to XLR jack adapter at My MBox Right Output or just using that 1/4 jack straight to the PA?

    2. If I'd build my own Amplification System (for that purpose).. what kind of Power Amp (Wattage, brand, etc) & Speaker Cabinet (configuration, wattage, impedance, etc) do you recommend?

    thank you
     
  2. I'd recommend getting a good passive, NOT active, DI box (ie Radial) for two reasons: the transformer isolation will keep nasty things like phantom power from frying your MBox and it will provide signal attenuation so you won't be hammering the board's mic input with too much level. For monitoring, I'd suggest getting a high quality powered speaker, otherwise you're just building a rig and using your computer as preamp which is pointlessly redundant.
     
  3. sevenorchids

    sevenorchids Supporting Member

    First of all, very brave of you to use a laptop on-stage. I'd go with a Muse Receptor over a laptop, but that's just me.

    You don't NEED a direct box, but you should probably have one (I like the Radial, myself). Not many soundmen are going to be comfortable with the whole laptop thing. Having a direct box will help, although they will probably want it pre-EQ.

    As far as power amps go, I've never had a problem with the QSC's that I have used. Plus, they have someone who frequents TB, and I like that. You'll also need some sort of cabinet too, yes? I'd suggest one of the Carvin LSx1503's or their active cousin, the LSx1503A. It's a full-range PA cabinet that many, including me, have used with good results. Just run out of laptop --> Power Amp --> LSx1503 and you'll hear yourself fine. If you go with the active version, it has the power amp built in. (others like Mackie actives, or EV, or any full-range PA speaker will do)

    Again, good luck!
     
  4. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    While PBG is absolutely right about a transformer preventing damage from phantom power, since the outputof the MBox is balanced I don't know if it can properly connect with the unbalanced input of most DI's, especially transformer-based ones which (I think) only have two wires going to the input of the xformer.
     
  5. bluesdogblues

    bluesdogblues

    Nov 13, 2007
    Hmm.. what should I do then?...
     
  6. Using a regular 1/4 unbalanced cable to the DI should work just fine, but you'll have to check your MBox manual to be sure.
     
  7. seamonkey

    seamonkey

    Aug 6, 2004
    Good job bluesdogblues - it's a great plugin.

    You can of course directly contact digidesign, but the trs outputs should have not problems dealing with phantom power. I have an ESI soundcard and it has no problems with phantom power. If the mbox wasn't designed right then it might have a problem but I would think the manufacturer would know. I've seen balanced outs from keyboards also hooked into boards with no problem if phantom is on.

    Also, it depends on what board you're going into, but most now have a bunch of inputs just for balanced line inputs like this. Or right below the XLR's on some are TRS jacks meant for line level inputs. Also phantom doesn't usually go through these in case you're worried. Or you might go into a effects return on on the channel. Many times a little separate mixer is added to a bigger board to mix down a bunch of things on stage. This would be no different.

    Sound engineers are use to hooking up PC's from keyboardist, and more and more are showing up on stage, and on the foh systems. They should have an easy time of it.

    The previous suggestion of a fullrange front-of-house/sound-reinforcement style speaker like a carvin LSx1503 is a good way to go. Carvin amps are also a good buy for poweramps.

    Happy playing - I know you've got good sound!
     
  8. This is potentially VERY bad advice. Unless the outputs have capacitor coupling for protection, which is extremely unlikely, 48 volts of DC seen through the output stage can do serious damage. I know that without a ground reference, it's technically "not there," but its not uncommon for the TRS jacks in audio equipment to short out. I strongly suggest that he ignore the suggestion to NOT use a DI. I have NEVER seen a professional keyboard rig that relied on a straight balanced connection directly out of the keyboard. On the contrary, that's where most of the damaged keyboards I've seen came from.

    This is fiction. EVERY single plug-based rig I have encountered has either been submixed or DI'd. Just because you like to shill plug-ins here doesn't mean that you actually know how to use them onstage or properly interface them with a PA.
     
  9. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    As PBG said, check the MBox user manual. If the output jack can be run unbalanced as well as balanced, then you'd just use a regular instrument cable to connect that output to a transformer-based DI box. If the output cannot be run unbalanced, then you don't need a DI at all, but you DO have to be very careful to check with the soundman to ensure phantom power is disabled.

    Seems like there must be a little utility box out there which would block phantom power in-line on a balanced line...
     
  10. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Dude, you are a better man than I. I would be so completely paranoid about using a laptop onstage. It's really got to be powerful to keep lag times unnoticeable, and you just never know when it's going to toe up and reboot on you out of nowhere. If you're looking to model Ampeg sounds I'd keep a Sansamp VT pedal with you as a backup. But I'm old and scared of technology.
    :bag:
     
  11. bluesdogblues

    bluesdogblues

    Nov 13, 2007
    Thanks for all the replies, I really appreciate em. Now I'm gonna check those Carvin Spkr that i just know.

    Actually I have done this (using Ampeg SVX onstage) few times. But before, the output of my interface (a MOTU Ultralite then) pluged straight to the Stage Bass Amp that miked or DIed to the PA.

    @Severnochid & JimmyM: Actually i've done it fewtimes before with a laptop that even 'worse' than my Apple Macbook now,.and thank GOD problem was none :)
    Alongside me on the stage is my DJ Friend who also rely everything on his Apple Macbook (Pro now)...and it was always ok too :)
     

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