Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Guitars => Topic started by: Justa on May 01, 2010, 07:39:14 pm
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There seems to be disagreement as to whether or not shielding causes tone degradation, lost highs and muddy bass.
There is also disagreement on whether or not to fully shield the pickup cavities or just do the bottom and not the sides.
What's the real scoop guys?
Thanks
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Shielding causes capacitance. Capacitance can form a filter which can filter out highs. Depends on the application.
Best bet is to try it and listen.
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That makes sense. Next time I shield a guitar and install new pups I will measure the capacitance before closing it up.
I have been in the "test mode" listening to it and I can't dial it in. I am going to try focusing on making some music rather than dialing it in see if that helps. My ears may be fooling me.
Thanks
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Yeah, it is tough to tell. I don't have that long of a tone memory. From testing a guitar without shielding, to then pullling it apart, sheilding the cavities, then putting it back together is too long for me to remember subtle nuances. However, I sure can tell if its muffled or too many highs cut.
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I'd go the exact opposite way. The reduced level of hum makes things sound better. Anything beyond that, you will never hear.
Gabriel
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All--
I'm old school--shield to kill the unwanted.
Creation Audio Labs has a device called "Redeemer" -- Can be installed in a Pedal, Guitar, or Amp input --
The unit retains the highs even with 25 foot cord. It even improves the sound of a cheap pickup somewhat.
www.creationaudiolabs.com
Mackie2
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Creation Audio Labs has a device called "Redeemer" -- Can be installed in a Pedal, Guitar, or Amp input --
The unit retains the highs even with 25 foot cord. It even improves the sound of a cheap pickup somewhat.
Uhhhh.....this is a vid of the Redeemer. Kind'a amazing (the 100' extension cord)
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I am guessing its a little preamp with a change in output impedance. Perhaps like a DI box.
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I agree, it must be a low impedance box. A friend of mine designed one of these YEARS ago. The "Hollis Research GX-10"...he sold it via magazine ads (mostly Guitarist Magazine) in the UK about 20 years ago. It had such low current consumption that it apparently improved the shelf-life of the battery by simply trickling charge out. The parts cost about 50 cents. He did a version with a wee bit of gain which made your strat a little hotter :)
I'm in the wrong business.
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A friend of mine designed one of these YEARS ago
Any chance he might give up some drawings or circuit diagrams?? :grin:
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Any chance he might give up some drawings or circuit diagrams?? :grin:
I'll see what I can do. I have a few laying around somewhere I think. I'd have to crack/grind/drill/melt/magic it open as they're potted in resin.
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Shielding causes capacitance. Capacitance can form a filter which can filter out highs. Depends on the application.
Best bet is to try it and listen.
ToN gave the main way it could affect tone.
You can look up the formula for factors that affect capacitance. Among them are area of the plates forming the capacitor, and the distance between the plates. If the area of the plates gets larger, capacitance goes up, and if the plates are placed closer together, capaciance goes up.
It's a bigger concerned with shielded cables, where the insulation between the shield and the center conductor forms a capacitor, and the "plates" (the 2 conductors) are fairly close together. But shielding in guitars is usually a matter of shielding the control and pickup cavities. The area of the shielding could be huge, but the distance between the shield and the rest of the circuitry is huge by comparison to a shielded cable.
I think it's a non-issue. People realized what I described, but didn't put numbers to it, look at where the "hidden capacitor is connected in the circuit, or realize that the resulting capacitance is likely in the fraction-of-a-pF range. If it shunted any signal, it would shunt extreme high RF energy, and that's good.