ITT, I build RobRob's Micro Champ

Discussion in 'Shock Brother's DIY Amps' started by guitarbuyer, Oct 10, 2016.

  1. guitarbuyer

    guitarbuyer Tele-Meister

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    Been a while since I've built anything and got the itch.

    My last build was the 5E8A, which happens to be one of my favorite amps I've ever played but as you can imagine, pretty hard to play at a volume that doesn't aggravate everyone in the neighborhood.

    http://www.tdpri.com/threads/5e8a-low-powered-twin-build-thread.450644/

    I've decided to build Robrob's Micro Champ. Looks quite interesting and as a Champ lover, should be right up my alley. And will be able to be played at a reasonable volume. I'm hoping it will make a good recording amp.

    So, I got everything ordered, or so I thought, and in the house.

    [​IMG]

    I dug out the power transformer that I just knew was the right one, and damn if it is not correct. It is the 40-18019, not 40-18027. I could probably make it work but I'll just pay another unnecessary shipping charge and order the correct one this afternoon.

    In the mean time, I'll get to drilling some holes in the chassis and get rolling. This will be my first time with a blank project box so I'll need to take my time and make sure all the holes get put in a logical place.
    Updates to follow.
     
  2. robrob

    robrob Poster Extraordinaire Ad Free Member

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  3. tweedman2001

    tweedman2001 Tele-Afflicted

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    Ditto. This is on my to do list. Just haven't got there yet.
     
  4. Sandhill69

    Sandhill69 Tele-Holic Silver Supporter

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    Double ditto...I too will do this although I am at this point still torn between an undrilled Hammond box and the lovely SF1 chassis that Rob suggests :)
    Excited!
     
  5. guitarbuyer

    guitarbuyer Tele-Meister

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    Ok, finally got a chance to get started. I got the chassis drilled out and mocked up for a dry run. Not bad.

    [​IMG]

    [​IMG]
    As soon as I finished that, I started looking for the rest of the parts I know are around here somewhere. Unfortunately, I cannot find the volume pots I know are in this house somewhere. So that means I will be wasting another shipping charge. I should have looked first prior to ordering. Still waiting on the right power transformer from Triode which still shows shipping in 2-3 days. perhaps I can call them and have them add the pots to that order since it appears to be backordered for now.

    Interestingly enough, while searching for them, I found in the closet two 5f1 chassis and a tweed cabinet with a 10" inch weber speaker I had forgotten about. So now I am thinking I may want to use one of those chassis. I'll have to remake the board as the one I had done is too long for the chassis. Hmm, not sure.

    [​IMG]

    [​IMG]
     
    robrob likes this.
  6. dan40

    dan40 Tele-Afflicted

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    I have also been wanting to build one of these in the near future. I wonder though, if mounting the preamp tube so close to the PT will cause any noise issues.
     
  7. guitarbuyer

    guitarbuyer Tele-Meister

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    Knocked out the board this morning. Sad now because I need to wait on some parts.

    Do you guys think I should move the tube to the other side? Wouldn't be much of a problem. I can scoot everything to the left and put the tubes over to the right side.

    [​IMG]
     
  8. Sandhill69

    Sandhill69 Tele-Holic Silver Supporter

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    A couple of questions, sorry to be so basic

    I assume that the turret board is not off the shelf. I can certainly cut and drill one, but is there a suggested layout somewhere?

    I ordered capacitors and all seemed to go well but when it came to the V1A and V1B coupling caps the parts list/spreadsheet gives me a 404 error when I look for details. There is enough of a price variation that I thought I'd better ask. I ordered

    https://www.tubesandmore.com/products/capacitor-400v-metal-film

    which at 38 cents per can just go in the odd parts box and be forgotten if they're a bad choice. I held off on ordering for example

    https://www.tubesandmore.com/products/capacitor-musicap-600v-polypropylene-coupling

    because at $12.16 each they're...more expensive ;).

    I know that the money for the MusiCaps or some other upgrade from the "generic metal films" might be very well spent. I just don't want to spring for them if the benefit would not follow.
    Thanks,
    Steve
     
  9. Dan Miller

    Dan Miller Tele-Meister

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    I scaled the layout from Rob's site (https://robrobinette.com/Champ_Micro.htm) to fit a 3" x 6" turret board (see attached PDF - note that I omitted the ss rectifier and added the double boost mod (the 0.68uf cap in green)). Print at 100%, tape to the board, and drill where indicated.

    For the coupling caps, I used these: https://www.tubesandmore.com/products/capacitor-mallory-630v-150s-axial-lead
     
  10. Dan Miller

    Dan Miller Tele-Meister

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    Well, the PDF didn't attach (edit to say, weird, now the PDF is attached to this one. go figure). Here is a jpg of my drilling template. If you use it, verify it prints at 3" x 6".

    Champ Micro for Drilling.jpg
     

    Attached Files:

  11. Sandhill69

    Sandhill69 Tele-Holic Silver Supporter

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    Thanks, Dan, just what I needed! I'll have AES add the Mallories to my order, an extra few cents, and the PDF for the board is printed and ready to glue down :)
     
  12. King Fan

    King Fan Friend of Leo's

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    Subscribed.
     
  13. dan40

    dan40 Tele-Afflicted

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    I only mentioned the preamp socket because it is good practice to place the sensitive first preamp stage as far from the power supply as possible. In most amplifiers you will see that V1 is at the far end of the chassis, away from the PT and rectifier. This also helps to cut down on long wiring runs from the board to the V1 socket. Long grid runs can act as an antenna and pick up noise so using shielded wire would be helpful in this case.
     
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  14. guitarbuyer

    guitarbuyer Tele-Meister

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    So sad - still waiting on the power transformer

    Order Status: Will ship in 2-3 days. (clearly a lie)
    Tracking:
    • USPS Shipment
    Order Date: 10/10/2016
     
  15. King Fan

    King Fan Friend of Leo's

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    Triode? Be very afraid...
     
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  16. guitarbuyer

    guitarbuyer Tele-Meister

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    Nothing to be afraid of. They either get one and ship it in the next couple of days or I cancel and find one elsewhere.
     
  17. King Fan

    King Fan Friend of Leo's

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    Exactly. Good plan.
     
  18. guitarbuyer

    guitarbuyer Tele-Meister

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    Lol. Shipped this morning.
     
  19. D'tar

    D'tar Friend of Leo's

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    Hope it's not an empty box. Lol.. I'll be watching this come together hoping you may follow up with some sound clips.
     
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