1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  
    TalkBass.com has been uniting the low end since 1998.  Join us! :)

Building an attenuator - problems

Discussion in 'Amps and Cabs [BG]' started by drewfunk, Dec 28, 2012.

  1. drewfunk


    May 10, 2010
    Olympia, Wa
    Hey guys, so i'm building a power attenuator for cutting the output on my Fender Pro Junior for quiet recording, and have run into an issue. I am following the build guide here

    I got it all wired up, double checked everything, hooked it up to my amp, and now i get no sound out of my speaker, just some amp hum. Anything i should look for? The only thing i did differently was use a stereo attenuator, but only used one side of it.
  2. will33


    May 22, 2006
    Might have to wire the two sides of the Lpad in parallel or series to let the signal through, but that would change your impedance. Should've ordered the 8ohm mono L-pad as instructed.

    Those things aren't all that robust with fullrange signal but may be OK for a 15watt amp, although it can put out close to 30 when cranked into distortion. I'd probably get the 100 watter just for a safety margin.
  3. BogeyBass


    Sep 14, 2010
    if your getting no sound then the wiring is incorrect.

    or you have a bad solder connection.

    or you might have made a solder bridge somewhere that is shorting out somewhere. maybe the case of the Lpad

    or the lugs coming of the Lpad are touching the metal case somewhere.

    but sometimes solder connections look good but they are not.
    keep the tip clean and get things hot enough so the solder flows nicely. cold solder joints are usually the culprit.

    or you switched the order of the lugs, so you might have connected it 3 2 1 instead of 1 2 3 or vice versa.

    which would be important since one lug is for ground
    and the others for the switch, so if any is reversed nothing is gonna work.
  4. drewfunk


    May 10, 2010
    Olympia, Wa
    I'm 99.9 percent sure all the wiring is correct, but i will check all the solder joints tonight.
  5. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    One picture is worth 1000 words...;)
  6. If you're getting hum through the speaker, but nothing else, something is really wrong, because that says the amp is working and connected. Like your guitar cable is bad or something.
  7. drewfunk


    May 10, 2010
    Olympia, Wa
    If i unplug the attenuator and run the speaker directly to the amp it works just fine, the instrument cable is ok.

    I will take some pictures tonight of the wiring.