Head shell - metal shielding...

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Riscchip, Jul 31, 2006.

  1. Riscchip

    Riscchip Member

    Messages:
    2,039
    Joined:
    Jan 4, 2002
    Location:
    Concord, CA
    Some of my amp heads have a piece of thin metal shielding stapled to the shell under the chassis. I gather this is some kind of shielding to prevent noise? In any case, what kind of material is this and where do you get it?

    Thanks!
     
  2. Fuchsaudio

    Fuchsaudio Member

    Messages:
    7,482
    Joined:
    Jan 3, 2002
    Location:
    Bloomfield, New Jersey
    We use adhesive backed aluminum tape, which Home Depot stocks (in the heating and air conditioning aisle). Before anyone makes any snide comments, lots of amp companies use this very same stuff.

    Steel, mu-metal or copper would work slightly better, but not by much. It provides shielding from RF (radio) and some hum fields from equipment placed on top of the amps. How important it is, is dependent on how much gain you have and how close it is to the top of the cabinet.
     
  3. Riscchip

    Riscchip Member

    Messages:
    2,039
    Joined:
    Jan 4, 2002
    Location:
    Concord, CA
    Thanks Andy! That's exactly the info I was looking for.
     
  4. donnyjaguar

    donnyjaguar Member

    Messages:
    4,242
    Joined:
    Nov 4, 2005
    Location:
    Canada
    I think the problem using duct tape is that the strips are too narrow. The good news is its not likely to come off at high temperatures. :)

    Copper flashing, in the plumbing aisle, is another option.
     
  5. Fuchsaudio

    Fuchsaudio Member

    Messages:
    7,482
    Joined:
    Jan 3, 2002
    Location:
    Bloomfield, New Jersey
    The tape is 3" wide, I think, and you simply overlap them, to maintain contact. They are self adhesive, and since they are used on heating and cooling duct work, the adhesive hangs-tough in a warm tube amp shell. We priced up one piece of copper, or aluminum, or mu-metal, and none were cost effective, and none did any better a job shielding the amp. Fender used window screen. If you like, buy real metal screen (some is nylon), and staple it in, but it's a pain in the butt to deal with IMHO.
     
  6. donnyjaguar

    donnyjaguar Member

    Messages:
    4,242
    Joined:
    Nov 4, 2005
    Location:
    Canada
    Noted. In my Traynors (the amp's, not the shoes otherwise you may be mistaken for the tin man of Oz fame) they used galvanized sheet metal, the likes of which you'd make ductwork out of.
     
  7. tonezoneonline

    tonezoneonline Member

    Messages:
    437
    Joined:
    Dec 15, 2003
    Location:
    central Illinois
    What I like best is the same stuff Marshall appears to use.It's aluminum flashing for roofs.It can be purchased in rolls of different widths at any big box home store.Lowes,Home Depot,Menards or your local hardware store.
     
  8. Reeek

    Reeek Member

    Messages:
    1,208
    Joined:
    Feb 1, 2005
    Location:
    Reno, NV
    My 1968 Sunn Sceptre head cab uses a fine mesh steel screen material. I wonder if the solid stuff is better?
     
  9. Wakarusa

    Wakarusa Member

    Messages:
    1,477
    Joined:
    May 7, 2004
    Location:
    Indianapolis, IN
    One thing to keep in mind is that these methods are only effective as an RFI shield if, when all is assembled, the tape/screen/metal is in electrical contact with the rest of the chassis.

    Google "Faraday Cage"
     
  10. Wakarusa

    Wakarusa Member

    Messages:
    1,477
    Joined:
    May 7, 2004
    Location:
    Indianapolis, IN
    I kinda like your Airline with the foil-backed paper taped to the bottom of the chassis :)
     
  11. Reeek

    Reeek Member

    Messages:
    1,208
    Joined:
    Feb 1, 2005
    Location:
    Reno, NV
    Todd, that amp sounds so friggin good. I'm debuting her at a HUGE musician's jam party in Wahsoe Valley this weekend along with my new Suhr Classic T and this combination is, to date, the finest tone and playability I have ever experienced as a guitar player. I can't wait to see the looks on everyone's faces when I play it for them. I'll probably never get to play it myself again all night long. There will be upwards of 30-40 musicians of all flavors there with all sorts of rigs.

    I know we all fluctuate over time with gear and tone for for today, this Airline and that Suhr Classic T are nothing short of amazing.


    And for the record, the other amp is shipping out next week to go into your queue ;)

    After the Bassman, I want to send the Sunn Sceptre.
     
  12. Wakarusa

    Wakarusa Member

    Messages:
    1,477
    Joined:
    May 7, 2004
    Location:
    Indianapolis, IN
    Hijacking the thread for a minute...
    You'll have to drop by the shop one of these days. Finally got a ChoralFlange (right here in the Emporium no less) and have been wanking around through a Deluxe Reverb and Princeton Reverb (both from 1965) in stereo chorus. The Airline was cool, but this is Nirvana. I'm hooked.

    We now return you to your normally scheduled discussion about RFI shielding...
     

Share This Page