Retrofitting an Attenuator with a Footswitch for bypass?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by brianr0131, Feb 22, 2012.

  1. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
    How difficult would it be to retrofit a passive attenuator with a relay and a footswitch jack to turn it on and off?


    Older Weber unit with a bypass toggle switch. The way I see it is I need power and a relay. Right? Do they make 120v relays? Are they dangerous?
    Could I get a 6v wall wart of some type and a 6v relay?

    Any help will be greatly appreciated. Also, if this isn't pretty simple and a DIY for someone with decent soldering skills and limited knowledge, I'll probably consult my amp tech. Just looking to save a few bucks if it's as simple as I think it is.

    Thanks for the help
     
  2. Blue Strat

    Blue Strat Member

    Messages:
    30,036
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)
    Here's one 120VAC coil relay. 6 Volters, and close, are also available. Yes, you can definitely do what you've described.
     
  3. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
    Thanks for the help. You say "here's one" but I dont see a link. Did you have a suggestion?

    Does anyone have specific suggestions for my needs?
     
  4. Blue Strat

    Blue Strat Member

    Messages:
    30,036
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)
    Ooops, I Googled "120VAC relay".
     
  5. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
  6. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
    OK so I have been searching a bit and either I could use specific direction from the good folks at TGP or I need to take it to a tech.

    The attenuator itself is an older Weber Mass 50 pic of back:

    [​IMG]

    As you can see there's no power at all on it so I need to get it there....there's also not a lot of room so maybe a small power adapter type with a female connector on the back and a jack for the footswitch? I guess somewhere inside the relay needs to mount up as well.

    I was considering a 120v relay and a power cable assembly like an amp has but I don't see how or why 120v is necessary or even practical.

    the female part for this:

    [​IMG]


    Seems drilling a hole for a wall wart jack would be much easier.

    Can someone help walk me through this a little better?

    basically, I want to make the bypass switch on here footswitchable.
     
  7. Blue Strat

    Blue Strat Member

    Messages:
    30,036
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)
    Go with your 6 volt plan. Google "6 VDC relay" , or 9 or 12, and use a wall wart to power it.
     
  8. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
  9. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
  10. Blue Strat

    Blue Strat Member

    Messages:
    30,036
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)
    Yes, for power for the relay. Then you'll need to wire it up.

    You may want DPDT in order to disconnect the speaker from the output of the attenuator when you're in bypass mode.
     
  11. Tone_Terrific

    Tone_Terrific Member

    Messages:
    25,264
    Joined:
    Dec 26, 2004
    Location:
    Canada-GTA
    I suggest a true bypass looper.
    You won't need any power at all.
     
  12. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
    I'm all ears...can you suggest one? I'm not familiar.
     
  13. Tone_Terrific

    Tone_Terrific Member

    Messages:
    25,264
    Joined:
    Dec 26, 2004
    Location:
    Canada-GTA
    All you need to do is bypass the load box.
    You probably could do that by running the leads from the bypass switch to an external mechanical switch (DPDT) built into a box but why hack up that box when you can just add one?
    You patch the load box into the loop.
    Here's the general idea:
    http://www.beavisaudio.com/techpages/PedalHacker/index.htm
     
  14. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
    What about the "moment" you're switching.....doesn't the OT not have a load? Wouldn't that be dangerous for the OT on the amp?

    also.....I don't think I want the speaker cable runs as long as would be necessary to have this "looper" box in a convenient location. Can't be good for tone. I know Weber and most Attenuator companies tell you to use the shortest cables possible
     
  15. Tone_Terrific

    Tone_Terrific Member

    Messages:
    25,264
    Joined:
    Dec 26, 2004
    Location:
    Canada-GTA
    What's going on inside the Weber box to prevent OT damage when you flip that switch, then?

    If you go the relay route, look for a 'make before break' relay to guarantee no open load condition.

    Long runs are common in PA applications. The loading imposed, with decent cable, would not be much.
     
  16. phsyconoodler

    phsyconoodler Member

    Messages:
    4,351
    Joined:
    Jul 11, 2005
    Location:
    calgary canada
    Use a Headlight dimmer switch.No relays and no power supply needed.
    Total mechanical switching.The older style footswitch they used to use for car headlights.It will handle anything you can throw at it.
     
  17. Blue Strat

    Blue Strat Member

    Messages:
    30,036
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)
    You mean the switch that turns on the high beams? Cool idea.
     
  18. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
    Thanks....this all makes sense. I appreciate the input.

    Seems like I'll need 4 long (10 foot plus) Speaker cables to do it with a bypass looper....unless I make the looper box and somehow make the switch part remote. Is that possible?
     
  19. brianr0131

    brianr0131 Member

    Messages:
    4,397
    Joined:
    Jul 19, 2010
    Location:
    Cherry Hill, NJ
    I like the sound of this....sounds simple. Any ideas on what these were actually called and where to look for them?
     
  20. Blue Strat

    Blue Strat Member

    Messages:
    30,036
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)

    You'll still end up routing all the speaker cable around the stage.

    Personally, I like the relay idea better.
     

Share This Page