Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Mr_Tickle on April 17, 2012, 01:42:19 pm
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Hi there.
New to this forum(and also amp building) so apologies if any questions I ask may seem simple.
I have been given all the parts to build a JCM800 2204. I have experience with repairing my own amp and also building stomp boxes and other electronic stuff.
I have no problem reading schematics however I do not know how to tell one end of an orange drop capacitor from the other.(never fitted one before)
I've checked all the values against the schematic and all is good(all new parts) but it is not obvious.
This may sound simple but I am stumped.
Please help. :BangHead:
Cheers
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Mr. Tickle,
Orange drops don't have a positive or negative side. They will work either way. But to complicate things just a little, they do have an outer and inner foil side, which if oriented correctly, may reject noise pickup a little better. The outer foil side on orange drops is no longer commonly marked, but I have read that the outer foil is to the right if you are holding the cap and reading the printing. The outer foil side rejects more induced? noise when it is oriented (pointed towards) the best path to ground.
There is a nice (better) technical explanation at Aiken amps: http://www.aikenamps.com/OutsideFoil.htm (http://www.aikenamps.com/OutsideFoil.htm)
Tod
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To complicate things even more,
Some time ago I found a webpage that explains how to build your own homemade outerfoil tester.
It'd be easy to build. Hope it helps!
http://www.soundgaragetales.com/amp-building/outside-foil-capacitor (http://www.soundgaragetales.com/amp-building/outside-foil-capacitor)
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That is a 50 watt Marshall. I have built quite a few Marshall type amps and never used Orange Drop caps. I am interested in what you think when you are finished building it. I have considered it and have wondered if they would sound good. Probably will. I have changed orange drops orientation from outer foil to ground and back again and I could not tell any difference. Maybe there is some, but I cannot hear it. Let us know how it sounds when complete. I have always wondered if they would open up the highs on Marshall type amps.
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The outer foil side on orange drops is no longer commonly marked, but I have read that the outer foil is to the right if you are holding the cap and reading the printing
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I have tested the OD caps in 3 different amps and that was not the case with the caps I tested. It varied from cap to cap & I could not establish a pattern.
With respect, Tubenit
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Ive used orange drops in several amps also and when testing them there is no rime or reason to there marking . one cap would be the way he said the other would be the opposite. so build the tester its easy and cheap and it works.
Bill
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For what it's worth, I do believe that proper orientation might have some impact on reducing noise.
However, after, gosh maybe 15 years of messing with this stuff, I've never bothered to ensure caps were properly oriented or even figure out which end is connected to the outer foil.
I briefly thought about trying to figure that out on the polypropylene filter caps I used on my current build, but decided to spend my time building rather than testing. My opinion is you're safe either way.