Rob Rob JCM800 6V6 Build

Discussion in 'Shock Brother's DIY Amps' started by DimensionofSound, May 16, 2021.

  1. DimensionofSound

    DimensionofSound TDPRI Member

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    Got my JCM800 up and running tonight. I think I’m going to get rid of the balanced bias pot and just do a bias pot. Sounds good despite the fact that I can only get it -45v. Need to mess with the bias circuit. Thanks Rob!
     

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  2. DimensionofSound

    DimensionofSound TDPRI Member

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    Quick sound sample on YouTube. Pre is cranked, master is low. Plugged into the high channel.

     
  3. 2L man

    2L man Tele-Meister

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    I built balance bias circuit to my last amp (Bassman 5F6A for 6V6) and it works so good that I will build same to next amps too. Sometimes there is quite a lot of difference in tube pairs which are supposed to be balanced. Bias point is just one point but still balance adjust balances circuit better.
     
    Last edited: May 16, 2021
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  4. 2L man

    2L man Tele-Meister

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    Sounds great and obviously volume is very low because I hear strings acoustic sound.
     
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  5. J. Bonkosky

    J. Bonkosky Tele-Holic Silver Supporter

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    That is a sweet build I have been contemplating something similar. Where did you get the cab and the chassis from? Also you can have both the overall bias control and the balance. That is how I setup my 72 super reverb. Just set the voltage then balance the tubes.
     
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  6. DimensionofSound

    DimensionofSound TDPRI Member

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    Thank you. Chassis is from Zack on eBay and the cab is from Mojotone. They did a sweet black tweed for me. Wanted something confusing looking (Fender/Marshall mashup) but all blacked out. I adjusted the bias resistor to 10k and it gets me to proper voltage now so I’ll probably leave it as is.
     
  7. cometazzi

    cometazzi Tele-Afflicted Silver Supporter

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    When you say "Zack on eBay" do you mean zachmdhunter? Chassis sure as heck looks like a Princeton Reverb chassis I bought earlier this year. I'd have some warm fuzzies if I knew zachmdhunter was here on TDPRI also.

    Sure would make it easy to ask him about custom setups down the road.



    Great build! Looks and sounds amazing!
     
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  8. DimensionofSound

    DimensionofSound TDPRI Member

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    Yes, the very same. That would be cool to be able to customize his chassis’. They are nice, especially for the money. It’s a Princeton chassis.

    Thank you for the kind words.
     
  9. cometazzi

    cometazzi Tele-Afflicted Silver Supporter

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    Yeah, I haven't finished my build yet but the chassis is excellent. Nice crisp bends, perfect holes and everything lines up perfectly. The steel is thick and beefy too. Great stuff!

    I feel like he has a comment on his eBay store about being able to do custom chassis too.
     
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  10. eslover

    eslover Tele-Meister

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    Really nice playing!

    I’m curious since the preamp volume was cranked and master was down, what preamp tubes do you have in there?
     
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  11. DimensionofSound

    DimensionofSound TDPRI Member

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    Thanks. JJ 12AX7s.
     
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