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MXR M-80 & Tech21 BDDI as stand alone preamp

Discussion in 'Effects [BG]' started by barroso, Dec 19, 2003.

  1. barroso


    Aug 16, 2000
    I am thinking to a backup amplifier.

    I would love to know if there is someone who uses a Tech 21 Sansamp, or a MXR M-80, or a Sadowsky stompbox as PREAMP directly in a Power Amplifier to the cabs.

    Is the signal from these stompboxes high enough for this purpose?

    thanks a lot
  2. VellaBass


    Aug 29, 2003
    London, UK
    If you mean the Sansamp BDDI stompbox, then the answer is no, not really, although they claim it is. You'd need to run it through a pre as well.
  3. craigb

    craigb G&L churnmeister Supporting Member

    Hey Barroso,

    I think the answer is "it depends". You can run any of those into the input of a power amp, the question is whether they provide enough signal to extract the maximum power from the power amp.

    I think you need to check the output voltage range for the pedal and the input voltage range for the power amp. I know that different power amps might expect different input ranges - I remember reading about some power amps that expected a larger voltage than some preamps (not just pedals, rack pres) were able to provide.

    IIRC some of the QSCs could not be driven to full output by some pres (Trace Elliot? definitely BDDI) but a modification could be made to them to get the full range.

    I know my backup plan is that if my RBI dies then I run the M-80 directly into my power amp (or just live with the signal in the mains and get turned up in the monitor depending on whether I'm going through the PA or not).
  4. I've used the BBDI directly in my QSC PLX2402. The available volume is dependant on the settings of the BDDI. I had good volume with the level set to max and the drive up around 2. If you wanted a tone that required the level to be lower, you may not have enough gain.
  5. Flatwound

    Flatwound Supporting Member

    Sep 9, 2000
    San Diego
    I'm using a SABDDI as a preamp, and yeah, the output is a little low. However, it's useable, and I have a Carver PM-350 (350w/ch @ 8 ohms), so I have enough power. However, I'm going to talk to Tech21 and ax them about what I should do to boost it up a bit. Apparently there's a fairly common mod to bring the XLR output up (something about removing a resistor), but I need the 1/4" out boosted up too.

    Having said that, I'm planning to stick with the SABDDI, because I really like the sound.
  6. BigTed


    Jul 1, 2002
    San Diego
    I've also used a sabddi as a pre in conjunction with a Carvin DCM 1000 power amp and a avatar 410. The sabddi's output was not strong enough for me. I love the tone from the sabddi, but I found myself cranking the power amp up 100% and still not being able to be heard over a loud drummer.

    There is a mod that can be done to your sabddi which will boost the output, by removing a small resistor on the board. Search the forum. There are a few threads regarding this.

    I know nothing of electronics, and didnt want to ruin the pedal. I ended up buying a real pre (if you can call a behringer bass vamp pro real) and was much more satisfied.
  7. Jazz Ad

    Jazz Ad Mi la ré sol Supporting Member

    The so-called mod is useless in this case.
    What it does is removing the -4 dB load on the XLR output to fit a regular table input.
    Removing the cap will bring the XLR level to 0 dB, same as the jack output.
    So basically if you want to go directly to a power amp, use the jack output.
    If your power amp only accepts XLR inputs, then use a converter rather than modifying a perfect unit.

    I use a BDDI as my only preamp but my situation is a bit different since I run it into active cabs. Those usually have a -10 dB input so the SansAmp fits perfectly.
  8. barroso


    Aug 16, 2000
    Dunno. Maybe a used QSC. actually i do not have nor the pre nor the PA.

    it's an idea i am trying to have a backup as cheaper as possible.

  9. bmc


    Nov 15, 2003
    Jazz Ad

    Curious to know which powered cabs you are using. They don't appear on your profile.

  10. Jazz Ad

    Jazz Ad Mi la ré sol Supporting Member

    I use a pair of Behringer B300.
    Far from being the best around, but they're dead cheap and an excellent value for the price.
    They're perfect with a 4 string bass but for a 5 string they leave to be desired.

    I highly recommend the Mackie SRM450 or the JBL 15 EON G2. Both give excellent results and if I could afford those I'd go with them instead of the Behringer.

    Going with active speakers is a great solution. It allows an incredible versatility. You can use them as a full bass rig, PA, wedges, monitors, combo, ...

  11. bmc


    Nov 15, 2003
    Thanks for that. I was at one of the local music stores in Geneva that had a powered Warwick speaker. Didn't have time to try it out. I'll check out the Behringers. I have BX300 for practicing. It hasn't let me down yet.