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FX send/return question

Discussion in 'Amps, Mics & Pickups [DB]' started by Chris Fitzgerald, Apr 12, 2009.


  1. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    I'm auditioning a couple of Phil Jones Flightcase amps for a review, and they both sound amazing with just the Full Circle running straight into them. The preamps sound fantastic, and I really wouldn't want to change anything about that sound.

    On the gig last night, I did find in a couple of places that I missed the option of blending in a mic signal, though. The amp does have an FX send and return on it, but no "blend" control. What I was wondering is if it would be possible to use this loop in the circuit to try to insert a mic signal with some sort of volume control so I could see how the amp would sound with a blended signal. Is this possible, and if so, what kind of cables would I need? I could try it with something as simple as a canon plug into a K&K wallet sized pre, and/or also with dedicated studio type pres.
     
  2. AFAIK, most FX loops cut out the preamp section when you have something plugged in to the Return jack, so you wouldn't get the "blend" you're wanting to try.
     
  3. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    I was thinking about a simple jumper cable into a "Y" cable. Effects Send out to one side of the Y (pickup signal), mic in through the other side. Since I'm using a dynamic anyway, I was thinking that I might be able to balance the two signals by the input gain and just let the mic be a constant that only raises or lowers by virtue of the master volume. Or would this not work for some reason that smart technically-minded people can understand?
     
  4. robgrow

    robgrow Supporting Member

    May 1, 2004
    Cincinnati, Ohio
    Chris, Unfortunately this may not work very well. Using a Y-cord as you described, the outboard mic preamp will see the source impedance of the Effects Send, which is probably very low (< 1K ohms) and the Effects Send will see the source impedance of the mic preamp which is also probably very low, therefore loading down both signals. You really need a small mixer to do this right.
     
  5. Uncletoad

    Uncletoad

    May 6, 2003
    Columbus Ohio
    Proprietor Fifth Avenue Fret Shop. Technical Editor Bass Gear Magazine
    Cannot really use a mic effectively with those rigs. It's why I left them by the side of the road too.
     
  6. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    And I'm guessing that if I use something like a small preamp to blend the two going into the front end, then it will change the impedance load on the pickup, right?
     
  7. I have a Flightcase 300 and love the sound. It is the most un-colored sounding amp. At low volumes it doesn't even seem like an amp is being used. However, I don't think you can blend a mic. I typically run a mic signal into the house P.A. system separately and that seems to really enhance the sound.
     
  8. Uncletoad

    Uncletoad

    May 6, 2003
    Columbus Ohio
    Proprietor Fifth Avenue Fret Shop. Technical Editor Bass Gear Magazine
    Yes and sound different in the Briefcase. Good or bad I dunno.

    One more thing to carry in a situation where you want less.

    As a pickup support amp where the acoustic tone is doing the heavy lifting that amp would kick the GK150's butt. If you like the mic thing like you and I do it's not enough.

    Fwiw if they did do a mixing preamp ala the Focus on the front end of that bigger box I think it would be formidable.
     
  9. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    Fremont, Ohio
    Editor-in-Chief, Bass Gear Magazine
    FWIW, Chris is talking about the Flight Case and Super Flight Case, both of which are one-channel designs. The Briefcase is a 2-channel design, and you could in fact run a mic in one channel and a pickup in the other and blend them. However, there is no phase control, and you have a 1/4" input on both channels.

    Tom.
     
  10. You could get a resistance mixer (like a DOD 240) and send the signal into the pre (no phase reverse, though), or a little mixer and send the line output into the return (that'll have phase reverse).
     
  11. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    Suppose, for the sake of the review I'm going to be doing on the Flightcase, that I wanted to try it with a blended signal. If I used the Focus as a blender, kept everything flat and kept the Focus pres at the barest minimum, couldn't I take the direct out into a cannon plug and then go into the front end of the Flightcase? Not ideal, I know, but would it work, or would it be impedance matching hell?

    Looks like the amp I'm dreaming of is the Suitcase head (two channels, same EQ bands set as a graphic instead of knobs) combined with the Super Flightcase cabinet design. With the impedance transformer on a dynamic, you could plug it right into channel 2 and blend away to your heart's content. I wonder how the sizes of the heads compare? The briefcase looks cool, but it's much heavier than the Super Flightcase, and I'd really miss the two "monitor drivers" that make the SF such a great design for double bassists.
     
  12. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    The mic signal might be weak compared to the level of your piezo going through the FX loop. So you will need to buffer and amplify the mic signal somehow, i.e., for the sake of experimentation, anything with gain and a low impedance output.

    To blend something into an FX loop, you could build what amounts to a passive mixer with a couple of (for example) 10k Ohm resistors, or to be fancy, a 10k pot which effectively gives you a balance control. Again, assuming that this is just an experiment, twisted wires and duct tape will get you to the point of testing the idea.

    An unresolved issue is phase. The mic could end up being in- or out- of phase with the piezo. If you have a phase switch on at least one channel, then you can proceed. If not, you might have to do something like flip your piezo upside down to decide which orientation you prefer. I just realized that flipping the Full Circle might be a hassle. You can also reverse the phase of a XLR microphone signal by swapping (IIRC, check me on this) pins 2 and 3.
     
  13. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    It would probably work well enough for experimentation. The high impedance of the Focus won't do any harm, but because the mic signal is low level, you won't get optimal signal-to-noise.

    But an XLR -to- 1/4" matching transformer will give you the gain boost to overcome that issue.
     
  14. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    Fremont, Ohio
    Editor-in-Chief, Bass Gear Magazine
    I've been suggesting something similar to Phil, along with an XLR input on one channel, variable phase on one channel (or at least a 180 degree switch), and a VHPF. :cool:
     
  15. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    That would be amazing, and I'd snap one up in a heartbeat. But even with just a Suitcase head in a Flightcase cab, the blending aspect would be fine. I plugged my Beta 57 into a cannon plug/impedance transformer, and it worked just fine into the front end. The way the PJB EQ bands are set "sort of" simulates a HPF, since the lowest band is set at 50hz and the second band at 160hz. And I've never seemed to need the phase switch when blending my mic and pickup in the AI stuff.

    As long as I'm dreaming, since we're using the Suitcase head, which normally pushes 4 drivers at 8 ohms/150 watts, let's go ahead and put it into the regular Flightcase cabinet rather than the Super Flightcase. That way, you could take the small combo to most gigs, and just add another cab when you need more. Yowsah!
     
  16. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    I tried the Focus II as a blender and it worked, but it sounded like the Focus rather than the PJB sound, which doesn't really help me evaluate the PJB amp very well. I played a trio gig on the little Flightcase 150 with just the pickup, and it was really nice. That amp gets surprisingly heavy on the bottom end though, so what about running the patented fdeck HPF in the effects loop? Will the impedance of the HPF change the sound, or will the pickup already be "loaded" impedance wise by the input? Or both?

    Where would I get this stuff...Radio Shack? If it was just this one time, I probably wouldn't bother so much, but since it looks like I'll be doing more than a few amp reviews, it might be a useful thing to have lying around if it works. Thanks for the advice!

    BTW, the Beta57 gets a pretty decent volume through the Flightcase without a preamp...certainly enough to use for what I do.
     
  17. Chris, how are you getting along with the the rear port on the PJB combo?
     
  18. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    The Flightcases are front ported. I am continually surprised by the way those tiny little speakers put out a sound that is sometimes *too deep*. It's gotta have something to do with those long tube ports in the design.
     
  19. My bad - maybe I was confusing it with the Markbass stuff. Thanks!
     
  20. Just a few observations on the Flightcase 300.

    It's Real easy to carry...very light. The two uploaded speakers make it real easy to hear on stage. The six 5 inch speakers react very quickly and are extremely accurate in terms of sound reproduction.

    Placement in a room is very important. If you place this combo next to a wall it will create a deeper sound. If it's placed in a corner the bass frequencies are accentauted, maybe a bit too much. Finally, the sound this amp delivers to the player who is typically within close proximity to the Flightcase is a bit different than the sound that is projected out in the room. On a few occassions, I have thought that my sound was a bit thick or too bassy standing close to the amp. However, out in the room, the sound was ultra clear and very punchy. It takes awhile to dial it in and get used to how clear and quick those 5 inch speakers project your sound.

    All the Best

    Trey

    P.S. I do not endorse these amps nor do I get any consideration for talking about them. I just like them!
     

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