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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

Rickenbacker M8E Capacitor Question

Discussion in 'Shock Brother's DIY Amps' started by OahuClay, Nov 14, 2017.

  1. OahuClay

    OahuClay TDPRI Member

    36
    Mar 7, 2009
    Longview, WA
    I picked up a ragedy M8E and it has a bad PT but alas I have a tweed champ transformer so thinking I'll use it as replacement.I want to put new caps in Bplus but the value is a bit odd these days although obtainable but I have quite a few 22uf @500v in my parts, so doubling them up I'd have 44 seems like a viable alternative.Do you think this would cause any problems?Any other reccomendations for better tone? rickenbacker_m8e.pdf_1.png
     

  2. Wyatt

    Wyatt Tele-Holic

    782
    Nov 3, 2004
    Last edited: Nov 14, 2017
    OahuClay and tubeswell like this.

  3. dsutton24

    dsutton24 Poster Extraordinaire Gold Supporter

    Dec 29, 2010
    Illinois
    You know, that thing is adorable! I've got an old low-watt Jensen speaker that I've been wanting to build a amp around, that schematic might be a good place to start.

    I'm sure you're way ahead of me on this, but be sure that you get rid of the Death Cap™ and install a three conductor line cord.
     
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  4. tubeswell

    tubeswell Friend of Leo's

    Jul 1, 2008
    NZ
    With the likely B+ voltage of around 360VDC from the Champ PT, you might want to bias the 6V6 with a 470R resistor
     
    OahuClay likes this.

  5. OahuClay

    OahuClay TDPRI Member

    36
    Mar 7, 2009
    Longview, WA
    Thanks for the input, yeah the death cap is gone and a new cord will be installed, there is a misprint on the value of the bias resistor it's 270 ohm not 270k but bumping it up to 470 per tubeswells sugestion, I think I'll add a bypass cap to it as well, any suggestions appreciated, its a pretty roomy chassis so not much limiting mods and it was cheaply built so can stand a few extra pieces, has ceramic tone caps so putting in orange drops and whatever else comes to mind
     

  6. dsutton24

    dsutton24 Poster Extraordinaire Gold Supporter

    Dec 29, 2010
    Illinois
    Thanks for that, I hadn't noticed the error. It wouldn't amplify much as drawn :)
     
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  7. Wyatt

    Wyatt Tele-Holic

    782
    Nov 3, 2004
    There is another mistake on that schematic.

    They screwed up the power string.
    • The 350V for the power tube plate should come off the first node
    • The 300V for the preamp plates should come off the second node, after the 10K dropping resistor
     
    tubeswell, OahuClay and Lupo like this.

  8. Lupo

    Lupo Tele-Holic

    625
    May 19, 2014
    Genova-Italy
    There should be some mistake in that schematics. After the rectifier, the voltage on the second 40u cap cannot exceed the voltage on the first one...
     

  9. Lupo

    Lupo Tele-Holic

    625
    May 19, 2014
    Genova-Italy
    Exact!
     

  10. noah330

    noah330 Tele-Afflicted

    Feb 10, 2009
    Maryland
    Those are great little maps. I have one and love it. There are two versions that I know of. Make sure you have the right schematic!
     

  11. OahuClay

    OahuClay TDPRI Member

    36
    Mar 7, 2009
    Longview, WA
    I see your point Wyatt, they drew the HV string backwards on the M8-E it should have been like the M8 below less the error on this B plus string grounding it! Note to self; Don't trust RIC schematics. rickenbacker_m8_sch.pdf_1.png
     
    Last edited: Nov 15, 2017

  12. OahuClay

    OahuClay TDPRI Member

    36
    Mar 7, 2009
    Longview, WA
    I went to the RIC site and they have corrected the error on the m8 schematic but the m8E still wont work, I left them a note
     

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