Embarking on a Champ Micro build

Discussion in 'Shock Brother's DIY Amps' started by Lavochkin, Sep 19, 2019.

  1. Lavochkin

    Lavochkin TDPRI Member

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    At the beginning of this year I was looking for a project when I stumbled on Robrob's tube amp site. A stunningly great collection of info, and it convinced me I could build a tube amp. I decided on the Champ Micro (need low power, current amp is a Blackstar Fly 3 watt) and had a couple of emails with Robrob. Finally getting started - I have amp parts and have built a current limiter for start up.

    I'll have to decide on format soon - for some unknown reason the normal Champ "controls facing up and tubes hanging down" bothers me. Does anyone have any thoughts on why or why not I should do the standard configuration? Champ Micro parts.jpg
     
  2. Edvin

    Edvin TDPRI Member

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    The normal layout is for putting chassis in a combo with faceplate upwards.
    If u want this as a stand alone head just put tubes and transformers on top.
     
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  3. sds1

    sds1 Tele-Afflicted

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    No reason you can't do front faceplate, tubes mounted bottom...

    Pro for front faceplate is of course visibility from the front.
     
  4. Lavochkin

    Lavochkin TDPRI Member

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    On his website Rob suggested upload a photo so other eyes can check component placement - seems like a good idea since this is my first build. A few things different from his layout. Added a filter cap bleed resistor and V1B boost cap, both documented on his site. He calls for a 25v rated boost cap, but where I got parts only had a .68uf at a 160v rating. Similarly, they didn't have a 39K 2W, so I used a 27K and 12K in series. Also the wire from the rectifier diodes to B+ is on top rather than underneath. Since nothing is soldered yet and I put that on last, I didn't want to try to get it on underneath.

    I also have a question about the power transformer. There are leads I won't be using - what is the normal way of handling that? Tape the ends? Cut them off short or just roll them up and stick them out of the way?

    Thank you, Matt

    Board rotated.jpg
    champ layout.jpg
     
  5. robrob

    robrob Poster Extraordinaire Ad Free Member

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    Your circuit board looks good.

    I like to heat shrink the extra wire ends then bundle the wires. If you repurpose the transformer in the future you'll be happy you didn't cut those leads.
     
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