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Splitting your Signal and Crossovers

Discussion in 'Effects [BG]' started by bluehevy75, Mar 30, 2009.

  1. bluehevy75


    Dec 1, 2007
    Chicago, IL
    I'm running two rigs...both tube driven...I want to send my bass signal to each of them. Highs on one and lows on the other.

    1. Is there an easy way to split the signal without loosing gain and (or) without "coloring" the tone?

    2. Does anyone have any schematics for a crossover I could build and mount on my pedal board?

    3. Besides the Rolls Tiny Crossover (http://www.rolls.com/product.php?pid=SX21) is there a commercially available crossover that will fit on a pedal board?

  2. bigchiefbc

    bigchiefbc Supporting Member

    Oct 9, 2006
    Rhode Island, USA

    I don't have a schematic in front of me, but essentially, isn't a crossover simply a split signal, with a high-pass filter on one channel, and a low-pass on the other? I'm sure there are pretty simple schematics out there that could do this.

    I know of nothing commercially available in pedal form to do this.


    Here's a page with a bunch of schematics on it, mostly crossovers and band-pass filters. You'll probably find what you're looking for
  3. Kooldac


    Oct 20, 2008
    You are correct, the money comes in on how well it attenuates said filters.
  4. bluehevy75


    Dec 1, 2007
    Chicago, IL
    I'm not sure I know what these mean or how to tell if a certain schematic would create a device that will do it well.
  5. Chunk Systems

    Chunk Systems

    Jul 15, 2007
    Sydney, Australia
    Effects manufacturer: Chunk Systems
    The kind of circuit you want for this is a 2 way Linkwitz-Riley active crossover. This kind of circuit sums to a flat frequency response over the whole band and has some nice phase coherence properties, although you'll probably screw up the phase with the EQ sections on the front end of your amps anyway. The Wikipedia page on Linkwitz-Rileys is a pretty good explanation.

    The circuit No 09 on the previously quoted website looks like it would do a pretty good job of it.
  6. surfingbird1


    May 22, 2008
    Correct me if Im wrong (basically because Im doing this as well).

    My plan was to send my signal (aphex comp, exciter, mxr eq)to a barge vb-jr, then inside that loop have another eq (first in chain) cutting lows and low mids then adding effects (muff, chorus, etc), then blending it with my original signal so the effects dont get muddy by my lows and when i add them back to the mix they are on top of the high end with my low end retained. With that being said, you could do similar but have the effects send "not return" and go out to your other amp or channel.

    Is this a bad solution? I have did a lot of thinking and I can't beat this one.
  7. bluehevy75


    Dec 1, 2007
    Chicago, IL
    I'm honored to be speaking to the person(s) responsible for the Brown Dog and the Agent 00.

    The suggestions you made sound very promising. I'm very interested in pursuing the Linkwitz-Rileys crossover. I'm just a little worried. I've made some pedals before (a/b, fuzz, loop), installed pickups and tone controls in guitars, installed Baxandall controls in an old tube amp while repurposing some some of the tubes for power. I feel like I can put that board together but I'm worried about the power supply. I've never made one. What are the odds that someone with only intermediate experience could get this thing built? I know it is a tough call as you don't know me but maybe you could let me know what to watch for.Also, do you think I would need a pot to adjust the frequency of the split or is the one provided good?

    Surfingbird, thanks for your suggestion. I know many people are using that Barge Concept unit. Part of me really just wants to run two rigs and have one being as near to a pure bass tone as possible. Maybe I'm crazy...but I'm having fun...

    Thanks guys,
  8. Chunk Systems

    Chunk Systems

    Jul 15, 2007
    Sydney, Australia
    Effects manufacturer: Chunk Systems
    I'm not really able to judge your electronics assembly skills, but it looks like a pretty simple job for anybody who's ever soldered up a PCB before. As long as you know how to identify the components and how to solder you'd probably be fine.

    It's not really possible to put a pot on this kind of circuit. From memory there are about 8 resistors that need to be changed simultaneously to modify the cutover frequency. You really have to pick a frequency and stick with it. Around 300Hz sounds like a pretty reasonable split point to me, but I guess that depends on why you think it's necessary to bi-amp in the first place.

    One other thing to watch out for. From memory the schematic on that site had a DC-coupled resistive voltage divider on the front with an impedance around 100k. Ideally, you'd want a higher impedance than that for bass and you'd probably want to AC couple. So, I would use a series capacitor of around 100nF at the front and then a resistor to ground of around 1M instead of whatever's shown there.

    Regarding a power supply, the simplest solution is to just use a 9V battery (or two 9V batteries if its a dual-rail circuit, which it probably is).
  9. I've got a friend developing a crossover distortion and he was saying that they had to develop a complicated and expensive custom pot to get the job done properly. It's probably not worth the trouble (to do the pot) unless you have a heavy electronics background to figure it out and the resources to have thousands made so they're not insanely expensive.
  10. synaesthesia


    Apr 13, 2004
  11. bluehevy75


    Dec 1, 2007
    Chicago, IL
    Thanks for the help guys. I'm going to order a board from EPS. The idea of making one just appeals to me right now. I'll let you know how it goes. It might be a month or so out because I've got a lot on my plate but I'll update this thread when I finish.

    Thanks again for the help. You guys rock.


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