Capacitor Outside Foil Placement Dumble

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ayan
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Re: Capacitor Outside Foil Placement Dumble

Post by ayan »

I hear you. However, I suggest you reconsider... the difference, depending how many of the vital caps are "flipped," can be very, very noticeable. After I started doing this, I volunteered to change caps for a few friends and not one of them was not beyond pleased with the results. At a minimum, do V1B, V2a and V2B. The tone caps, arguably, have less of an effect and the lower impedance side will depend on your tone settings in this case. The cap across the bass pot I found to be irrelevant, as was the V1B NFBL cap etc.

Cheers,

Gil
norburybrook wrote:Thanks. Much as I love you guys, I'm not taking them out. it's a PIA as there's always the possibility something might fall through when trying to remove those caps and then end up having to remove the whole board.


Next time :D or if I get really bored one day and I don't have a million other jobs that need doing around the house :D



Marcus
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norburybrook
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Re: Capacitor Outside Foil Placement Dumble

Post by norburybrook »

Gil,

Ok, you're sounding very compelling :) however I've still got this weird crackling sound coming from my amp that I can't seem to trace.

Once I get to the bottom of that then OK, I'll do it.


Marcus

p.s. If you've got a minute have a listen to the sound file I posted on my build thread and see if it rings any bells with you.
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ayan
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Re: Capacitor Outside Foil Placement Dumble

Post by ayan »

I will if you can point me to the right place, maybe post a thread link? :)

G.
norburybrook wrote:Gil,

Ok, you're sounding very compelling :) however I've still got this weird crackling sound coming from my amp that I can't seem to trace.

Once I get to the bottom of that then OK, I'll do it.


Marcus

p.s. If you've got a minute have a listen to the sound file I posted on my build thread and see if it rings any bells with you.
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Re: Capacitor Outside Foil Placement Dumble

Post by norburybrook »

sorry Gil, right below this thread.

here you go.




http://ampgarage.com/forum/viewtopic.ph ... 5&start=75



marcus
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ayan
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Re: Capacitor Outside Foil Placement Dumble

Post by ayan »

Replied there, and I don't have a good answer. :(

G.
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sonicmojo
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Re: Capacitor Outside Foil Placement Dumble

Post by sonicmojo »

I think this is a good thread to sticky!

I had to search for it again a few weeks ago when I got a batch of caps in the mail. I usually do them all at once and mark them with the poor man's method.
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Re: Capacitor Outside Foil Placement Dumble

Post by andresound »

I built an TW express and oriented caps according to supplied markings. I have since decided to do a 2nd Gen DUmble build and decided to check for outer foil orientation, only to find, the supplied markings (black line), were NOT always correct!!

I have therefore decided to check all caps on my Express buid (a real PITA!!!). I will report back on my findings if you guys are interested.
If it sounds good, it is good! Trust your ears
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Re: Capacitor Outside Foil Placement Dumble

Post by drew »

The photo from the fifth post in the thread is on a stupid file-hosting site that required me to turn off my ad-blocker to look at it. So I'm attaching a copy here.
You do not have the required permissions to view the files attached to this post.
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Re: Capacitor Outside Foil Placement Dumble

Post by pompeiisneaks »

sonicmojo wrote: Wed Aug 26, 2015 5:24 am I think this is a good thread to sticky!

I had to search for it again a few weeks ago when I got a batch of caps in the mail. I usually do them all at once and mark them with the poor man's method.
I agree and I stickied it :)

~Phil
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Re: Capacitor Outside Foil Placement Dumble

Post by glasman »

Here is a great article on the subject. I ran across them in about 2003 as I was researching to build my first kinda clone.
http://www.aikenamps.com/index.php/whe ... capacitors

I even gave GIl Ayan an oscilloscope so that he could test his caps. Gil was a lot of help for me when I first started messing with these things.

Gary
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Re: Capacitor Outside Foil Placement Dumble

Post by Reeltarded »

Im such a monkey I cant even edit posts without replying to myself in a quotation.
Last edited by Reeltarded on Fri Dec 14, 2018 11:48 am, edited 1 time in total.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
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Re: Capacitor Outside Foil Placement Dumble

Post by Reeltarded »

Reeltarded wrote: Fri Dec 14, 2018 11:45 am
martin manning wrote: Tue Aug 25, 2015 12:02 am You'll have to remove them, but an alternate way to find the outer foil is to connect them across the input of an amp. One orientation will produce more hum, and in that case the outer foil lead is connected to the tip terminal of the amp's input jack. This is most easily done by wiring up a DPDT switch with short clip leads so you can reverse the "polarity" of the cap quickly.

I found a positive and easy way to make the amp a testing instrument.

Put a large choke over the first stage cathode. The choke is screwed to a board. The board has a pair of nails a couple inches from the choke.. The choke is on long leads and oriented to least hum. A cut 1/4" cable with clips on in is clipped to the probe nails. Touch the cap leads to it, flip it. Least hum is outside to ground.

I'm a monkey.
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Re: Capacitor Outside Foil Placement Dumble

Post by pompeiisneaks »

Reeltarded wrote: Fri Dec 14, 2018 11:45 am Im such a monkey I cant even edit posts without replying to myself in a quotation.
You need to put your text after the last [ / quote ] part :D

You're what we call in tech a 'chaos monkey' :D

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Re: Capacitor Outside Foil Placement Dumble

Post by Reeltarded »

pompeiisneaks wrote: Fri Dec 14, 2018 4:45 pm
Reeltarded wrote: Fri Dec 14, 2018 11:45 am Im such a monkey I cant even edit posts without replying to myself in a quotation.
You need to put your text after the last [ / quote ] part :D

You're what we call in tech a 'chaos monkey' :D

~Phil
I fat fingered the reply and untyped the po.. then realized what I had done after hitting submit. The forum is a certain sort of devil.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
hermannbjorgvin
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Re: Capacitor Outside Foil Placement Dumble

Post by hermannbjorgvin »

I got help from my friend who is an electronics engineer with a scope, we tested every single cap for my new #002 clone.

For testing we hooked the caps up to his scope and measured the noise, holding them between our fingertips. The noise in an amplifier would probably be considerably more but that's just my uneducated guess.

We found a BIG difference between orange drop capacitor foil placement, the noise seemed to drop around 50-70 % when measured on the oscilloscope.
For the mica caps and other non orange drop caps it seemed to also have an effect, so we marked those just for kicks, there was a difference but not a substantial one, closer to 20% really, sometimes hard to tell.

Hope that helps everybody who is thinking about cap foil placement, my friend was not convinced and thought this was closer to voodoo but after explaining to him and him measuring with me on his scope we were both a bit surprised by the difference.

For a huge build like a Dumble why wouldn't everybody do this
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