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Thinking in building a tweed amp - 1st timer

Discussion in 'Shock Brother's DIY Amps' started by tube.tone, Jul 23, 2009.

  1. JohnnyCrash

    JohnnyCrash Doctor of Teleocity

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    When idling, but what about under load/working conditions?

    I know the cathode voltage will swing a decent bit under load, so wouldn't the resistor under load make more of a difference?

    I've been trying to figure out true wattage/dissipation for cathode biased amps and then the Load Line sheets come in... at which point, I forget about it.

    This is also part of the confusion in many amp makers calling cathode biased "Class A."

    After all of the reading, at the end, I'm still confused :)
     
  2. tube.tone

    tube.tone Tele-Meister

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    Hello, I am back with the first pictures. I have received the kit Yesterday and i started to take the first steps. Although, I already have a few questions for the seniors:

    1- When I installed the power transformer, I noticed there's a red and blue wire, and 2 white and red wires (one is labeled with #6). Were do they go?
    2- One of the two red wires from power transformer to rectifier is labeled with a #5 , but wiring diagram shos that they connect to #4 and #6, any
    clue? Please see attached photo.

    3- Using the socket key as a reference can you help to identify the pins (1,2,3,...)? I prefer to double check before start soldering.

    Thanks

    putting the chassis together:
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
  3. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    I think the numbers on the transformer wires are just for identification -- not for which tube pins they connect to. They "key" in the tube base goes between pins #1 and #8, if that helps. (Pity they don't number the pins on the sockets like they did in the old days!)

    - Scott
     
  4. tube.tone

    tube.tone Tele-Meister

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    Thanks! what you guys usually do with unused wires from power transformer? Tape, heat-shrink?

    I have started the soldering in the chassis...

    [​IMG]
     
  5. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    Coolness! Now's the time to decide how you want to wire the heaters... if you want to keep the heater wires down against the chassis, you'll want to put them in first. If you want the signal wires to hug the chassis, and prop the heater wires into the air (like some blackface amps), then obviously do them last. ;)

    Re: unused wires. I bend each one over, and roll several layers of electrical tape over it so it won't make contact with anything, then bundle it with other unused wires and tuck them away.

    - Scott
     
  6. tube.tone

    tube.tone Tele-Meister

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    Update,

    Here is a pic of filament wires route planing, I order tohave room to work I will have to solder it after circuit board is instaled:
    [​IMG]

    Circuit board ready to solder:
    [​IMG]

    I have opted for TDA filter capacitor:
    [​IMG]

    Orange drop for all other capacitors and carbon comp resistors, so far I have decided to respect the original values:
    [​IMG]
     
  7. tube.tone

    tube.tone Tele-Meister

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    Last edited: Sep 11, 2009
  8. sjhusting

    sjhusting Tele-Afflicted

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    Connecting the 100-ohm resistors like that is fine. It elevates them above ground by the cathode voltage, which reduces hum.

    In tweed chassis, I prefer to tuck the heater wires against the lip of the chassis; this keeps them further from everything else.

    Also, if you are interested in keeping as close as possible to original parts, if those ODs are 715s, that type of capacitor didn't exist in 1957; you would be closer with a 716 or a Mallory. But I don't think it makes much difference. Others do.

    steven
     
  9. celeste

    celeste Friend of Leo's

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    716's are basically 715's with copper leads. 225's would be more original.
     
  10. sjhusting

    sjhusting Tele-Afflicted

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    Right. Faulty memory.
     
  11. tube.tone

    tube.tone Tele-Meister

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    Hey guys, thanks for the imput. The amp is going faster than first thought! I had to place an order for more wire. I have also ordered another pilot lamp assembly, I was not pleased with the one that came with kit.

    Here is a few more pictures,

    Instaling the controls and jacks:
    [​IMG]
    [​IMG]

    Full Chassi waiting for the extra wire:
    [​IMG]
    [​IMG]

    Cheers
     
  12. tube.tone

    tube.tone Tele-Meister

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    Sorry for the spam guys! Today is a very importanday day, the chassi received a new house...
    [​IMG]
    [​IMG]
    [​IMG]
    Best
     
  13. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    Looks very nice and tidy so far! Spam away! :cool:

    - Scott
     
  14. tube.tone

    tube.tone Tele-Meister

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    Thanks! It's not dificult at all, I'm just concerned about the testing procedures... I am sure I'll need help.

    I'll keep you postest
    Best
     
  15. Jelle

    Jelle Tele-Meister

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    Looks great and thanks for posting; I love pics :p
     
  16. tube.tone

    tube.tone Tele-Meister

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    Thanks for the support; this forum is an inspiration for me.

    I have purchased this kit with a European power transformer. Actually, it has, 120v, 220V, 240v taps. I will be using 220V tap. I’ll be moving back to Portugal (my origin Country) next Month.

    For now I have soldered the 120V, so that I can perform the first tests. Later on, when I back to Europe I assume that I just have to desolder the 120V and solder the 220V tap. Is this correct? Should I have any other concern?

    Also, I would like to give my positive feedback on Weber Kit (rest in peace) is a great value for your buck, to say the least. I have ordered almost complete; cabinet, board, transformers, hardware and 12A150 speaker.

    As I have mentioned before, I placed a separate order or capacitors and resistors (Orange Drops, TAD and carbon comp resistors). Also, I ended up using a different cloth wire supplied by Tube Depot (who also does a great service).

    Ted Weber Kit has arrived very well packed, chassis is all chromed and looks pristine, it came with all perforations needed for board and transformers. The cabinet itself is beautiful, strong construction, well finished and ready to instal the chassis. No extra work required, except thight a few screws.

    So far, needless to say that I am very happy,

    Regards
     
  17. sjhusting

    sjhusting Tele-Afflicted

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    When you move to Europe, change the mains fuse to 1/2 what it is now.

    steven
     
  18. tube.tone

    tube.tone Tele-Meister

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  19. sjhusting

    sjhusting Tele-Afflicted

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    The red/blue lead is for the negative bias voltage, if you are building a fixed-bias amp. You are not building one, though, your amp is cathode bias, so you don't use the red/blue lead.

    The red/white leads are used if you want lower HV - the Weber transformer puts out 340-0-340 and 270-0-270, and you use the ones you need for the voltage you need.

    In both cases, clip the lead so there is no bare wire, and shrink-wrap it so that there is no chance of being suprised by a few hundred volts. Make sure the leads are secured so they do not flop around in the chassis.

    steven
     
  20. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    "NC" = not connected. :D
     
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