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Fishman Pro-Eq as Pre-amp

Discussion in 'Amps and Cabs [BG]' started by JJBluegrasser, May 20, 2003.


  1. JJBluegrasser

    JJBluegrasser Wannabe Snazzy Dresser

    Apr 17, 2003
    USA, Raleigh, NC
    The other day I was in a music store, and I was trying out a QSC PLX 1602 power amp. I tried running my bass through a Fishman Pro-Eq straight into the amp and I couldn't get any volume at all. But then we hooked a small mixing board into the amp with the Pro-Eq going into board, and it sounded great. Can anyone tell me why the Pro-Eq won't work as a pre-amp for the PLX 1602?

    Thanks,
    Jason
     
  2. tuBass

    tuBass

    Dec 14, 2002
    Mesquite, Texas
    I've heard the PLX series has something missing the the other QSC series does not. I would be interested to see your results with other power amps, as I have a fishman too (that I LOVE) and am thinking about trying to use it as a pre-amp. (which mixer were you using, and what was the order of the chain? I am very interested.
     
  3. JJBluegrasser

    JJBluegrasser Wannabe Snazzy Dresser

    Apr 17, 2003
    USA, Raleigh, NC
    Hey tuBass,
    Thanks for the quick response.

    The mixer I grabbed was a Yamaha MG12/4 series. Nothing too fancy (it did have a seperate mic pre-amp though).

    The order of the chain was Bass->FM Pro-Eq->Channel 1 of MG12/4 -> QSC PLX 1602 -> Yamaha speaker cab in the store (I'll be using an EA 1x12 once I get everything.)

    I also tried this into a QSC RMX amp, and got the same results, so I don't really think it is the amp.

    Thanks, Jason
     
  4. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    The Fishman simply is not meant to drive a power amp, that's all.

    The primary application is to plug into an instrument amp or mixing board, so the output is in the same range as a bass which could be a good 10 to 20 dB lower than the level that power amp wants to see.
     
  5. mflaherty

    mflaherty Supporting Member

    Oct 9, 2001
    I dug out my owners manual for my old-style (metal case) Pro-EQ. Nominal output level is listed at -17dBV. According to this calculator that is 0.1413 Vrms. I looked at the QSC specs here which show that amp needs 1.2Vrms to be driven to full output. So, you somehow need to increase the output voltage of the Fishman by a factor of 10.

    That is exactly what the Yamaha mixer did for you.

    Most power amps need around 1Vrms. Most battery powered preamps deliver a lot less.

    You could get a little Behringer MX602A mixer like I have for around $60 and use it with the Fishman, or you could look at other preamps with more output. I would start with the AC powered ones.
     
  6. JJBluegrasser

    JJBluegrasser Wannabe Snazzy Dresser

    Apr 17, 2003
    USA, Raleigh, NC
    Thanks for all the help guys. This forum is great. I knew someone around here would know the answer to my question. Thanks alot!

    Jason
     
  7. DaveB

    DaveB

    Mar 29, 2000
    Toronto Ontario
    I have a Pro-EQ Platinum Bass that I bought to use with my upright. But I have used it with my Modulus Q5 into an Eden WT-500. The Fishman works fine with an amp. I found the most effective use with the Q5/Pro-Eq/Eden (that's a LOT of pre-amps)is to bypass the Eden pre-amp and use the Pro-EQ with the Eden power section alone.That works great which tells me that you can use the Pro-EQ very effectively with a QSC.
    If my goal was to drive a power amp with an electric bass I'm not sure a Pro-EQ Platinum would be my first choice. But it is a relatively inexpensive and effective alternative.
     
  8. JJBluegrasser

    JJBluegrasser Wannabe Snazzy Dresser

    Apr 17, 2003
    USA, Raleigh, NC
    Hi DaveB,
    I am actually an upright player, but I thought this question could be better answered in the electric bass forum. Sorry for the confusion.

    When bypassing the Eden pre-amp stage, do you physically bypass it somehow, or just use a bypass switch. If the later, then that may explain why the Pro-Eq still works. Maybe it is an impedance mismatch issue that I am seeing as well and when you use your's, your impedance is matched correctly by the Eden's front end.

    Jason
     
  9. mflaherty

    mflaherty Supporting Member

    Oct 9, 2001
    Have you tried your upright w/Fishman into the Eden amp? Which Eden input do you use?
     
  10. tuBass

    tuBass

    Dec 14, 2002
    Mesquite, Texas
    Would the mixer have to have phantom power? I just ordered a 502 this morning, and it doesn't have phantom power. Would it still power up the fishman enough?
     
  11. mflaherty

    mflaherty Supporting Member

    Oct 9, 2001
    Phantom power is only used by certain microphones, usually expensive condensors. I just looked up the UB-502 and it is cute! I think it should work well for your needs, and probably for JJBluegrasser as well.
     
  12. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    don't forget the DI's......
     
  13. tuBass

    tuBass

    Dec 14, 2002
    Mesquite, Texas
    Thanks for the info, I am pretty ignorant on things like mixing boards and mics. i only ordered the UB502 becuase my current setup at church is a amp/cab on stage, and a fishman that I am using as direct box to go through the mains. To hear myself on stage, I have to have the amp turmed up to a point that the soundguy is turning me off in the mains, which means that certain points in the church can't hear me because of the direction my cab is facing. I will be using the mixer as a headphone amp and blending the sound of the main mix, with a separate line for just my sound, turned UP of course.
    In the next few months we will be getting electronic drums, so the days of headphones were rapidly approaching, I'm just a little ahead of the game.
     
  14. mflaherty

    mflaherty Supporting Member

    Oct 9, 2001
    Petebass makes a good point. Several active direct boxes use phantom power. I don't think it would be necessary in most bass rigs, though. If you get in a concert or recording situation, the FOH mixer or recording console that the DI is patched to will probably have phantom power.
     
  15. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    Most DIs that CAN use phantom also can be powered by a battery.
     
  16. DaveB

    DaveB

    Mar 29, 2000
    Toronto Ontario
    JJB and mf - I bypass the Eden pre-amp stage by plugging the bass into the Platinum EQ and then the Platinum EQ into the Eden effects return (on the back panel). This bypasses the Eden pre-amp BUT it is pre-compression (which you can disengage anyway).The input impedance on the Platinum EQ is 10 megohm.The effect of this is the exactly the same as using a QSC or other power amp with the Platinum EQ.

    Now having said that I have experimented with this on elctric gigs and works great but with my Q5 it doesn't sound any better (or worse) than just going into the Eden pre-amp so I don't use the Platinum with electric...just with upright.If don't bypass the Eden pre-amp with the upright the tone is noticeably more muddy/less clear.

    I think I will ultimately get rid of the Eden and get a Euphonic Audio 1800. But I must say that I would have no hesitation about using the Platinum EQ with a good power amp for both URB and electric.