Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on September 09, 2010, 02:33:39 am
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HI Guys, The PT i have for my TOS (Timbo's Overdrive Special :grin:) is a hammond 290DEX. It has an orange shield wire, could someone guide me to it's connection point and what does it do. Thanks
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Faraday shield. Attach it to any chassis bolt
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Hi Guys,
I've had a few PT's now with the shied wire on it and have done just what you said, attach it to the chassis lug.
What I'm curious about is why do they bother?
Would it not be easier and more cost effective to attach it internally at the factory?
Safer too? In this litigious age most companies don't leave any thing up to an individual to do when they can do it themselves.
are there other considerations here I do not know about?
Sorry for the HIJACKING Timbo, but this has been on my mind a bit for a while now.
Ray
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What I'm curious about is why do they bother?
An electrostatic shield picks common-mode noise capacitively-coupled between primaries and secondaries. It's a very low Z element and works best when connected to earth thru a dedicated low R lead. Is it worth the bother in geetar amps? I'm not sure.
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FWIW I try to connect the PT secondary center tap directly to the negative end of the "reservoir cap" (IOW first on power rail). The Faraday shield should be connected to "earth" ground as FYL says. Important? Not necessarily, but might be helpful if you have a ground lift for your amp.
Cheers,
Chip
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Hi Ray , Any extra input to these questions can only be more helpful to those who do not have allot of technical knowledge. Thanks