Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

Mallory 150 outer foil

Discussion in 'Shock Brother's DIY Amps' started by JuneauMike, Oct 5, 2017.

  1. JuneauMike

    JuneauMike Tele-Holic

    887
    May 5, 2015
    Alaska
    So this is not a big deal and I'm not going to sweat it. But I dragged an amp and guitar cable out last night and wanted to satisfy for myself that my coupling caps were going to be oriented in a way that minimizes excess noise in a couple of amps I'm working on.

    I tested three brands of caps, all were .022uf and two of the three had markings indicating the outer foil direction. The Mallory's did not. I followed this method and my results were consistent with what he was talking about. The only difference was that I didn't use a bare input jack, I just unscrewed the casing of one of my 6-foot short guitar cables and plugged directly to the solder joints.



    However, I couldn't detect a sound difference with the Mallory's. I thought I had read somewhere that some of these film capacitor actually has a foil shell wrapped around them that is disconnected from the inner layers, but I've never had the luxury of owning enough Mallory caps to actually cut one open.

    Again, I'm not going to worry about it. Without any information I am going to orient the caps with the assumption that the outer foil is to the right as you read the lettering on the cap. If their advertising propaganda is to be believed than they are non polarized and so orientation shouldn't be an issue, right? I was really just curious. Is there another DIY method of testing this short of buying an oscilloscope or building another component that, lets be honest, I'm not going to build.
     

  2. Outlaws

    Outlaws Tele-Meister

    157
    Jan 16, 2007
    None
    I did this and made the box. I had a Mesa Mark V with a 412 almost fully cranked to hear the difference for the test. Not saying it doesn’t matter, just that testing this way requires serious volume.
     

  3. JD0x0

    JD0x0 Friend of Leo's

    Age:
    27
    Feb 22, 2009
    New York
    Non-polarized caps will function in either direction, but that doesn't make outer foil orientation (if the cap has it) insignificant. If you have outer foil properly oriented in your amp, you will have better noise rejection. Obviously, it will make less difference in a 'lower gain' circuit compared to a high gain circuit.
     

  4. JuneauMike

    JuneauMike Tele-Holic

    887
    May 5, 2015
    Alaska
    Yeah, no question they will function fine in either direction. Noise rejection is what I'm after.
     

  5. JuneauMike

    JuneauMike Tele-Holic

    887
    May 5, 2015
    Alaska

    Hmm. There was absolutely no difference that I could detect. None. Maybe I'll use my Big Muff tonight. But I sorta think based on what I heard that no amount of volume is gonna make a difference. But nothing ventured ....
     

  6. Phrygian77

    Phrygian77 Tele-Holic

    639
    Apr 30, 2016
    Crawfordville, FL
    I just did this with some 150s and there was a very noticeable difference. I used alligator clip leads on the end of a shielded cable, and I had the amp turned all the way up.
     

  7. sds1

    sds1 Tele-Meister

    Age:
    41
    369
    May 4, 2017
    Orlando, FL, USA
    Can you find the noisy end more efficiently with an oscilloscope? If so, what's the procedure?
     

  8. JuneauMike

    JuneauMike Tele-Holic

    887
    May 5, 2015
    Alaska
    My understanding is that yes, a scope would work better. As to the procedure:
    Step 1: Spend a ton of money.
    Step 2: Learn how to use the scope.
    Step 3: Use it.
    Step 4: Store it away for years and years until you need it again. ;)

    Thanks guys. Sounds like I should take another run at it. Gotta tell you, this approach seems very dodgy, but way cheaper than buying the right test equipment. Ha.
     
    theprofessor and sds1 like this.

  9. D'tar

    D'tar Tele-Holic

    940
    Jan 11, 2013
    WNY
    Hold the cap over an ac power cord. I use the one to the amp i am testing with. This helps you hear the difference. The .022's are hard to hear sometimes
     
    King Fan likes this.

  10. Mr Green Genes

    Mr Green Genes Tele-Afflicted

    Feb 23, 2016
    MI
    Yup. The easiest way to remember it is that the signal should flow in the same direction as the printing/lettering.

    Some people hear a distinct difference, others hear no difference at all.

    As far as I'm concerned, it's no more effort to install them in one direction than it is the other, so why not just install them that way as a matter of course?
     

  11. Outlaws

    Outlaws Tele-Meister

    157
    Jan 16, 2007
    None
    Should was only correct in 4/5 of mine.
     
    JuneauMike likes this.

  12. JD0x0

    JD0x0 Friend of Leo's

    Age:
    27
    Feb 22, 2009
    New York
    Sometimes the caps get flipped on the production line. Outer foil is not always inherently on one end relative to the printing on the cap.


    The easiest way is to plug a 1/4'' cable into the amp, and touch one lead to the tip and one lead to the sleeve of the 1/4''
    One direction will have notable hum, the other will be significantly quieter. The quieter direction will have outer foil to the 1/4'' cable sleeve. Connect outer foil of cap to the side of the circuit that has less impedance to ground.
     

  13. Mr Green Genes

    Mr Green Genes Tele-Afflicted

    Feb 23, 2016
    MI
    If it's crucially important to you in a non-polarized capacitor, testing each individually is the only way to be certain.

    For someone who doesn't want to go through and test every capacitor, it's a good rule of thumb, and will be right 80% of the time, according to the limited data available.

    If the capacitor is being housed inside a Faraday Cage (like an amp chassis), I really don't think it's going to make a world of difference.
     

  14. dsutton24

    dsutton24 Poster Extraordinaire Gold Supporter

    Dec 29, 2010
    Illinois
    An amp chassis is not a Faraday cage. Tube amps are very noisy internally, and they're precisely the kind of place where you want to pay attention to cap orientation.
     

  15. JuneauMike

    JuneauMike Tele-Holic

    887
    May 5, 2015
    Alaska
    My amp was not at an excessively high volume (because its annoying and I like my comfort) but I'll try tonight with the volume up and, failing that, with a muff pedal between them. If the casing is in fact manufactured in a way that separates the inner film from the outer casing (such as I described in my OP) is there a workaround? Touching the ends of the capacitor casing rather than the cylindrical surface wouldn't do it, right?
     

  16. JD0x0

    JD0x0 Friend of Leo's

    Age:
    27
    Feb 22, 2009
    New York
    There's internal interference going on in a tube amp. That's why shielded grid wires are often used and lead dress is extremely important in high gain amps. It makes a noticeable difference, in noise floor, IME.
     

  17. Mr Green Genes

    Mr Green Genes Tele-Afflicted

    Feb 23, 2016
    MI
    I stand corrected.
     
    sds1 likes this.

  18. Outlaws

    Outlaws Tele-Meister

    157
    Jan 16, 2007
    None
    I made it with a switch and a mute switch and had to listen closely. If i had to do it the other way with the volume and noise of flipping it around would make it very hard to hear the nuance in hindsight. It’s there, but it’s very minor.
     

  19. gourmetsaint

    gourmetsaint Tele-Meister

    Age:
    58
    123
    May 17, 2017
    Australia
    I did this last night with six Mallory 150s using an old Marshall vs15 practice amp. When the outer foil end was connected to the tip of the guitar cable, there was definitely a different sound as I held and released the caps with my fingers. When the other way around, I could pinch and unpinch the caps and no difference was heard.
     

  20. Phrygian77

    Phrygian77 Tele-Holic

    639
    Apr 30, 2016
    Crawfordville, FL
    Don't touch anything except the cap. Pinch it in the middle with your index finger and thumb. Both ways will produce hum, but one way will be noticeably quieter, that's the foil side connected to ground.

    On the 716Ps I just tested, two 400VDC .022uF, and two 600VDC .1uF, the labeling was opposite for the different voltages/values.
     

IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.