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Why is my 800rb so much louder than XLS1000

Discussion in 'Amps and Cabs [BG]' started by relsner, Jul 28, 2012.

  1. relsner


    Feb 16, 2010
    Ok, help me understand volume relative to watts, or at least specs. I am playing my USA Fender P ---> VT Bass Pedal --> Crown XLS1000 in bridge mode with yes, a correct bridge cable, down to a 8 ohm 400 watt 2x10 cab. Great sound for sure. Now I take the VT and XLS out and drop in my 1984 GK 800rb and the volume blows away the XLS. Even at max volume on the bridged channel the difference is very significant. I know one is a class D amp and the other is not, yet from a shear wattage specs perspective the GK should only be doing 100 watts @ 8 ohms, and the XLS 700 bridged-mono.

    How can I be sure the XLS is truly bridged besides seeing the display say BYPASS BRIDGE?

    What am I missing?

    Thanks for your help
  2. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    Both set ups through the same 2x10? i'd think 2 things, firstly, the 210 should be the limiting volume factor, and secondly, the GK head is preamp/poweramp in one, where the VT plus poweramp is not. getting a poweramp to produce full power requires the input sensitivity to match from the preamp. Perhaps the VY is incapable of driving the poweramp to full power. Either way, it's the speakers that make the sound. More spkrs = more loud. A 2x10 is not much in that regard.
  3. relsner


    Feb 16, 2010
    Yes, same bass and same settings, same 2x10. Only swapped rb800 for VT/XLS combo. I agree more speakers = more volume. But all things being equal on either end, I assumed the XLS would be capable of driving the speakers to 'at least' the same volume as the GK. I have other cab combos (4x10, 2x12) that I have tested this with and the case is always the same, the 800rb drives the speakers to a greater volume.

    I suppose the VT is not providing enough input to the XLS. However, when I leave the VT in line with with GK the sound is even bigger.
  4. First the 800RB is 200 watts into 8 ohms with a huge reserve.
    That said, bridging increases the voltage swing from the power amp to the speakers. With only a 210 hooked up you will run into power compression very quickly from a bridged amp. Try the Crown with one side driven only and see how it compares. I suspect in bridged mode you are heating the voice coils more than doing actual movement with the 210.
  5. relsner


    Feb 16, 2010
    Actually, I cannot tell the difference (volume-wise) in this setup when in mono Bridge mode, or simply using a single channel in stereo bypass mode. Oh and I did use the correct cables for the test, not the same one as I do know the difference for the bridged cable.

    Hmmm, I was hoping for lightweight power and the tone of the VT but not at the expense of overall volume. Maybe the XLS has to go back?
  6. cableguy


    Jun 4, 2009
    North Bend, WA
    The VT pedal doesn't have enough gain to fully drive the power amp. I had this same issue with my VT's & BDDI into a power amp. But the RBI (same tech 21 sound) would drive it fine. You could look at a mic pre to put after the pre (Rolls 41 or something I think) or stick with your 800RB. If you're just looking to go lightweight and like the sound of you 800RB maybe look at the MB500 with the VT in front.
  7. wave rider

    wave rider

    Jan 5, 2005
    I think the output of the VT is a little low for the input sensitivity of the Crown. Maybe add a clean boost pedal after the VT?

    The Peavey IPR series has a much lower input sensitivity in case you decide to return the Crown.

  8. The XLS series has an input sensitivity of 1.4 V to get full output so you'll need a preamp that has more power than the VT pedal.

    I keep reading threads here of people experiencing your issue. I don't read of people having this problem, however, with the Peavey IPR series which has a greater input sensitivity, about 0.75 V to get full power output IIRC.

    Another solution I've seen is to use a tube preamp (eg ART) between the VT pedal and amp to boost the signal, but then you've got one more piece of gear to futz with :meh:

    Edit: frankly, if it were me I'd stick with the VT pedal and the 800RB so you'd have the variety of sounds, that's a very powerful amp and I've rarely needed more power than that (I use 2 JBL 15s w/an '87 800RB), and when I did, I simply went into FOH (DI) and kept my rig as stage monitor/tone source.
  9. Flatbass


    Mar 13, 2004
    The 800RB is not that heavy, is it?

    Why not run the VT into the GK? You might even try running the VT into the effects return of the GK, bypassing the preamp.
  10. relsner


    Feb 16, 2010
    Ok, so you are all correct. Thanks for your replies. My buddy has a guitar volume pedal and a ART mic tube preamp and we tested it with the XLS power amp. Big Big difference when the signal is boosted before the amp. So now I know. Anyway I love the 800rb and the VT adds that much more sound capability, I was just looking for another setup that might be light and simple to compliment some of my other stuff.

    Plus, who doesn't enjoy playing with new toys.

    Learned lots, but took the XLS back. However, while I was there I did play with this Mesa Boogie Scout that has me interested...
  11. LOL, the GAS never seems to go away :D

    Those Scouts are great amps, btw.
  12. Clark Dark

    Clark Dark

    Mar 3, 2005
    who makes the 2x10 8ohm cab???
  13. relsner


    Feb 16, 2010
    Th 2x10 8ohm cab is a custom built with two 4ohm eminence BP102-4 run in series. I have two of them. A local cabinet maker make them similar to Avatar specs. They sound tremendous.
  14. will33


    May 22, 2006
    Between the 800rb and the VT pedal, you got about any sound you'll need for bass ya know.:D

    The input sensitivity thing is something you have to watch out for when putting together component bass rigs. If you don't have enough juice going in, you won't get enough coming out and it can neuter otherwise powerful amps. Unfortunately, there is no standard, or "commonly accepted" levels when it comes to this stuff and it's not very well advertised either. Most any mixing board has plenty of gain available so it's not a big deal there, but that's not a bass rig. Just one of those things. The little Tube MP has many wonderful uses. This sort of thing is one of them.

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