Shielding a speaker?
Moderators: pompeiisneaks, Colossal
Shielding a speaker?
I've been working on an old Gibson Scout lately. The other day I put in a speaker, a 12" Pyle Driver. Everything says the Scout had a 10", but the baffle is cut for a 12", shrug.
With the speaker in, the reverb is humming like crazy. I've moved the tank around, the only place I lose the noise is a couple of feet from the speaker. Is it possible to create a shielded bag or something, or am I going to need to get a different speaker with a smaller magnet? Ideas?
With the speaker in, the reverb is humming like crazy. I've moved the tank around, the only place I lose the noise is a couple of feet from the speaker. Is it possible to create a shielded bag or something, or am I going to need to get a different speaker with a smaller magnet? Ideas?
Re: Shielding a speaker?
Are you sure you didn't flip the tank?
As in...rotate it on the long axis?
As in...rotate it on the long axis?
Re: Shielding a speaker?
I own a Scout. I'll confirm it is a 10" so yours has been modified. I'd agree on checking tank orientation before doing anything else. Open side is down. I don't recall which side the connectors are on but I think the cable length is not adequate to allow end to end rotation. Mine is in a closet that is hard to get to or I'd take a look. Sorry, about to leave for vacation, so I wouldn't be able to actually do that for another week.
I'll also ask the obvious. There is a bag for the tank and the bag is screwed to the cab floor. Is yours in a bag?
Beyond that, I think I might think about a piece of aluminum flashing, which is relatively easy to cut and bend. You can probably make a modified doghouse above the tank and screw it in place without too much trouble. As I recall (could be wrong), the cable is fairly standard fare coax, so there is already an outer shield on that.
Thinking about this...your view may differ...it may be simpler (although a bit more work) to cut a new 10" baffle and put in the correct size speaker. If you can be patient, I'll get mine out when I return and give you a good measure on the placement of the hole.
I'll also ask the obvious. There is a bag for the tank and the bag is screwed to the cab floor. Is yours in a bag?
Beyond that, I think I might think about a piece of aluminum flashing, which is relatively easy to cut and bend. You can probably make a modified doghouse above the tank and screw it in place without too much trouble. As I recall (could be wrong), the cable is fairly standard fare coax, so there is already an outer shield on that.
Thinking about this...your view may differ...it may be simpler (although a bit more work) to cut a new 10" baffle and put in the correct size speaker. If you can be patient, I'll get mine out when I return and give you a good measure on the placement of the hole.
Re: Shielding a speaker?
I don't see how the speaker would cause that. It's a fixed field, the magnetic equivalent of DC. Maybe recheck the cables, especially their grounds.
Re: Shielding a speaker?
Thanks for the replies. I've moved the tank all around the box to try to find a quieter spot, no dice, although some are louder. With the speaker moved away from the box the noise goes away.
There is no bag in mine, I plan on making one once I figure out the shielding issue.
I may have to go to a 10", but I'd like to try a doghouse or something first.
There is no bag in mine, I plan on making one once I figure out the shielding issue.
I may have to go to a 10", but I'd like to try a doghouse or something first.
Re: Shielding a speaker?
Get or make a bag. IMO, it's essential.
You can buy vinyl upholstery tolex-like fabric at the likes of JoAnn Fabric. You don't need much. In case you don't know, to make a neat bag, you sew it inside out. For this you could just as easily do it any way you like. It isn't a fashion item!
Aside: besides me, I wonder how may guys here actually know how to use a sewing machine. I can't really sew anything that needs much more than a straight line. My mother was a dress maker. She showed me how the machine worked when I was about 20 years old so I could hem my own blue jeans. I'm short and the standard length is nearly always too long. It was a useful lesson. 40 years later, I still do them on my own. This isn't high fashion...that goes to a real tailor.
You can buy vinyl upholstery tolex-like fabric at the likes of JoAnn Fabric. You don't need much. In case you don't know, to make a neat bag, you sew it inside out. For this you could just as easily do it any way you like. It isn't a fashion item!
Aside: besides me, I wonder how may guys here actually know how to use a sewing machine. I can't really sew anything that needs much more than a straight line. My mother was a dress maker. She showed me how the machine worked when I was about 20 years old so I could hem my own blue jeans. I'm short and the standard length is nearly always too long. It was a useful lesson. 40 years later, I still do them on my own. This isn't high fashion...that goes to a real tailor.
Re: Shielding a speaker?
I can make a bag, and I can see the advantage for isolation, but that wouldn't affect the hum, would it?
Re: Shielding a speaker?
You sure it's not the relationship of the reverb take to the transformers?
I build and repair tube amps. http://amps.monkeymatic.com
- JazzGuitarGimp
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Re: Shielding a speaker?
I wonder if the speaker's magnet could be interfering with or possibly amplifying the flux coming off the transformers? Just pondering out loud here. It might be interesting to build a set of extension cables for the reverb tank so that the amp chassis could be removed from the cab, keeping the same relationship between the speaker and the reverb tank.
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Re: Shielding a speaker?
I have experienced this and/or relationship to the tubes.You sure it's not the relationship of the reverb take to the transformers?
Re: Shielding a speaker?
I did a little test this morning, removing the speaker. You guys are right. It's not the speaker. I'll start checking other stuff. Thanks.
Re: Shielding a speaker?
Reverb pan in bag screwed to bottom of cab. Keep far away from the PT as possible.
Mark
Mark
- JazzGuitarGimp
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Re: Shielding a speaker?
And keep the output end of the tank (the return back to the amp) on the opposite side from the PT.M Fowler wrote:Reverb pan in bag screwed to bottom of cab. Keep far away from the PT as possible.
Mark
Lou Rossi Designs
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and Schematic Capture
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