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6V6/6L6 blackface champ with solid state bridge rectifier build

Discussion in 'Shock Brother's DIY Amps' started by tubescent, Mar 29, 2010.

  1. tubescent

    tubescent Tele-Meister

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    I've finally assembled all my parts and just need to order caps and resistors tomorrow. here is a layout i have drawn up and i wondered if one of the learned around here could just have a look and see if it looks ok before i go ordering. really chomping (or is it champing) at the bit to get building this week and post some pics here.
    [​IMG]
     
  2. Dr.Ow!

    Dr.Ow! Tele-Meister

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    Looks fine except you are showing the PT's CT(0) led to the rectifier, instead of ground or led to a standby switch. I assume only an oversight in your layout draw, but thought I'd mention just in case-that won't be good..
    I buy various values of all resistors near the values needed so tweaking in those areas is easy and not waiting for a new order. They are cheap so only adds a couple $'s.
     
  3. tubescent

    tubescent Tele-Meister

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    thanks dr.ow! - i just ordered as i thought maybe people were a bit sick of me so i best get on with it ; )
    nice tip on the tweaking with the extra resistor values - i'll pick em up somewhere if i need 'em i suppose.
    i'm not sure exactly where i've gone wrong with the centre tap - i currently have a wire leading from the PT centre tap to pin 8 of the 6V6. is that wrong? you mention rectifier? did you think 6v6 was rectifier or am i messed up?
     
  4. celeste

    celeste Friend of Leo's

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    You have not gone wrong with the CT, he is thinking it is the CT of the HV winding, it is the CT of the heater winding and you have connected it to the cathode of a cathode biased power tube to elevate the heaters and reduce heater induced hum. Your HV winding has no CT, that is why you needed the 4 diode rectifier, so no issues with placing it wrong. I am not a huge fan of using the cathode to elevate heaters, but it is often enough. I prefer to split up the PS safety bleeder resistor to give me a node 50-75v above ground, with an added cap from that node to ground, connect the heater CT there. I would ot bother changing it not, but if you have hum higher then you want, and you can fix it by running the heaters from a 6v lantern batter, try it my way.

    The only change I would make is to split up the grounds and return each to the negative end of the filter cap that feeds that stage, volume and tone grounds to the ground of the preceding stage
     
  5. Dr.Ow!

    Dr.Ow! Tele-Meister

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    Thanks Celeste for clarifying the CT issue. I was not certain, just trying to help catch some possiblity. I have only experience with simple CT based HV and never any elevated ground stuff.
     
  6. tubescent

    tubescent Tele-Meister

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    some progress:
    [​IMG]
     
    Last edited: Apr 11, 2010
  7. limbe

    limbe Tele-Afflicted

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    I see that you are using the 240 volt tap on the primary of the transformer which is the standard voltage in England.If you would like to see how EU managed to make 230 volt the standard voltage inside EU without doing a thing go to http://www.coffeetime.wikidot.com/uk-eu-mains-voltage-harmonisation
    I think it´s pretty funny.
    Limbe
     
    Last edited by a moderator: May 4, 2010
  8. tubescent

    tubescent Tele-Meister

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    [​IMG]
    [​IMG]
    I am gonna ad trem and reverb later so that is what the extra holes are for. I tell you I aint ever making my own chassis again - bit too much diy for me :eek:
    I used step drill bits and that worked out pretty good except MAKE SURE YOUR DRILL IS ON A FAST SPEED!!! I skipped to a slow speed at one point thinking that would help me be more accurate but the step-bit just gripped the chassis and the whole thing spun round like a propeller and sent stuff flying. Pretty dangerous but my fault.
     
    Last edited: Apr 29, 2010
  9. tubescent

    tubescent Tele-Meister

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    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    Finished the wiring coming off the power supply today.
     
    Last edited: May 6, 2010
  10. tubescent

    tubescent Tele-Meister

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    i've done all the wiring now except i broke the 1.5k resistor on the 6v6 and i need to get some clips for the speaker lead. i've really found this hard hard going if i'm honest but it's my own fault for biting off more than a newbie should. if i could go back in time i would say loud and clear "your new to this, get a kit and don't try and do too much, just enjoy a simple project". i have trouble with this moral generally methinks :rolleyes:
    could someone tell me what the clips that attach to the speaker are called?
    i need to buy a couple and i didn't know what to call them at an electronics shop and the guy didn't have a clue what i was talking about.
     
    Last edited: May 19, 2010
  11. celeste

    celeste Friend of Leo's

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    Sometimes called Spade connectors, because the male looks like a shovel blade. More specifically called Faston connectors. The two most common sizes here in the US are .187 and .250
     
  12. tubescent

    tubescent Tele-Meister

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    thanks celeste. i also just found a supplier calling the "crimp connectors".
     
  13. kevinlekiller

    kevinlekiller TDPRI Member

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    I have a bag from mouser, I bought some for my champs speaker : .250 FF RECPT 18-14 Tyco Terminals , part number : 571-422822 ( if you are using mouser ). Good luck on your build, everyone needs a champ :)
     
  14. tubescent

    tubescent Tele-Meister

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    well i finished it today and got a bit excited when the pilot came on but then it blew after 2-3 seconds :(
    have checked all the wiring again and it seems right.
    where do i go from here?
     
  15. Wally

    Wally Telefied Ad Free Member

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    Check those filter caps. ARE they in reverse orientation...that is, are they positive to ground. MY eyes tell me that they are in incorrectly. I could be worng.
     
  16. fezz parka

    fezz parka ---------------------------

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    What Wally said. Electrolytics are backwards.
     
  17. Wally

    Wally Telefied Ad Free Member

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    Well, not all of the electrolytics...but the filter caps are definitely in backwards. I would suggest checking that bias cap, also. The violet colored board cap seems to be oriented correctly.
     
  18. Wally

    Wally Telefied Ad Free Member

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    tubescent, are you still with us? Easy mistake to make in the excitement of a first build, bud.
     
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