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To Pad or Not To Pad...That Is The Question

Discussion in 'Amps and Cabs [BG]' started by Turtle71, May 2, 2010.


  1. Turtle71

    Turtle71 Supporting Member

    Aug 11, 2009
    Madison, WI
    OK, this seems like it could go in several different forums, but I think it fits best here?

    I have a question about using the "input pad" on my amp.

    Here's how my signal chain "flows"...I Run my bass (an Active Ibanez SR505) into my Shure SLX wireless bodypack, then from the receiver into my pedal board (assorted Boss pedals & such) and from there directly into the input of my amp (SWR WorkingPro 400).

    The Shure bodypack transmitter has a 10dB pad switch that I have turned "on", but the amp also has a 10dB pad switch that I've been using also, am I effectively cutting my signal strength 20db? if so, which pad should I turn off? Is there a benefit from turning one off as opposed to the other?

    The whole reason I'm asking this is because the other day at rehearsal I accidentally must have bumped the pad switch on my amp, and I suddenly found myself with a whole pile of headroom I didn't have before, and it wasn't clipping and sounded great, but I was afraid to damage the amp, so I turned the pad back on....any thoughts?
     
  2. bluestarbass

    bluestarbass

    Jul 31, 2007
    Indianapolis
    Only use 1 pad. Doesn't really matter which one, I'd probably use the amp pad. As long as your not clipping your not doing any harm.
     
  3. lowfreq33

    lowfreq33

    Jan 27, 2010
    Nashville
    Endorsing Artist: Genz Benz Amplification
    The pad on your wireless should only be used if you're clipping it's input. The pad on your amp should only be used if you're clipping the amp's input. You may not need either.
     
  4. Turtle71

    Turtle71 Supporting Member

    Aug 11, 2009
    Madison, WI
    Well the Shure receiver has a "input level bar" on the front and it spends most of time in the yellow, but once in a while I'll pop the red light if I really dig into the B string. So I probably should leave the pad "on" for my transmitter, or I fear I'll spend all the time in the "red" and damage the wireless. And before anyone says it...Yes I know my bass has a volume knob...:p

    I think I'll try turning off the pad on the amp side...It was nice have the "extra power" I'll just have to really dig in next time to set my input gain correctly so I don't clip it.

    Thanks for the input guys! :bassist:
     
  5. You turned the pad off on the amp accidentally, and got LOUDER, you didn't get any more headroom by turning the pad off. The amp output puts out what it puts out regardless of the pad settings. It just takes a hotter signal to drive the amp to full output when you have the pad engaged.
    If you thought you had more headroom when you switched the pad because you elimiated distortion, you turned it ON by mistake. You could have been overloading the input before when you dug in, and the distortion was the input, not the amp clipping.

    Engage the pad, volume drops. Turn off the pad, volume increases. It's a bit like "gears" (for those who drive a manual transmission) for the input gain control of the amp. You want to have the input knob in a comfortable place, so you have room to make subtle adjustments. If you have to have your input gain at 1 to avoid clipping, hard to make small ajustments, there's no room. Engage the pad, now the input knob has to be at say 5 or 7, so there's room to make small adjustments.

    If the wireless is in the red, use the pad on the wireless. If the clip light on the input of the amp lights a lot, try the pad. If you're not getting any clipping, with no pads, don't need them.

    You might need either pad, or none, or both. Depends on your settings and bass.

    Just avoid distortion, and you're fine.

    Start with the earliest pad, you always want it up as far as it can avoiding distortion to get the best signal to noise ratio. Adjust wireless pad, then amp pad and input gain, then set the master volume wherever you need it to get the volume you need.

    Don't worry about your 500 watt amp only putting out 250 watts when the master volume is halfway up. It will still put out 500 watts if you provide enough signal, which you will be able to do if you've adjusted the input gains correctly.

    My thought is with bass -> pedals -> amp, the pedals are very likely to result in a hotter signal and require the pad to be ON than not. I'd guess its more likely you accidentally turned the pad ON by mistake, and less distortion made you think you had more headroom. the volume would have gone down though, if that happened. It's not entirely clear as to what you meant by "headroom" went up.

    Randy
     
  6. Turtle71

    Turtle71 Supporting Member

    Aug 11, 2009
    Madison, WI
    Yea, after I posted the original post, I realized it may have been a little unclear...

    It didn't necessarily give me more headroom, it was just the overall volume went up noticeably, it definitely wasn't "perceived" volume, this thing was LOUDER.

    That's went I started messing around and found that my input pad was turned OFF (button out). So I messed around for a few more minutes with the pad OFF and realized I wasn't clipping the input stage at all (there is a red light for that). I actually had to turn my output volume down to get to the level I usually play at...So by headroom, I guess I meant "with the input pad OFF and with the input gain set correctly, I now have the ability to go even louder on the output side of things (or so it would seem) So that's when it occurred to me to post this question for those that may have similar set-ups.

    Thanks for the input Randy!
     
  7. seanm

    seanm I'd kill for a Nobel Peace Prize!

    Feb 19, 2004
    Ottawa, Canada
    As others have said, only use the pads if you are clipping. You won't hurt the amp by not turning on the pads. The pads are there to handle very hot signals that could cause distortion.
     

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