5F2 style build

Discussion in 'Shock Brother's DIY Amps' started by Lindsay, Oct 17, 2014.

  1. Lindsay

    Lindsay TDPRI Member

    May 13, 2011
    Goulburn Australia
    Greetings all, this is my first thread on this forum but I've been a lurker on here for a few years.

    I live in Australia a few hours away from regular TDPRI poster Telenut62. I've built a few amps over the past four years but have no formal training, just like many on this forum I enjoy the process of learning and creating.

    My previous builds have been higher wattage so I wanted a practice style amp for my 9 year old to take to music practice and something that wouldn't be too loud at home.

    I decided on a Champ style build but have used transformers wound by a friend. The output transformer has two taps at 5K and 7K for an 8 Ohm load.

    I made the chassis myself from 2mm aluminium and TIG welded the ends in.

    The enamel paint finish was baked in my BBQ, well burnt may be a better description after I got confused between Fahrenheit and Celsius.

    The circuit is a mix of 5F2 and 5F2A with switching for the first stage bypass cap and the NFB.

    It also has a 9 Hy choke. I have 318V on the plate and the preamps at 170V, so I'm about 20V above the original 5F2 values stated on the schematic.

    The circuit board is loosely based of the Hoffman board with a few changes to grounding. I tried a bit of cloth covered wire but I ordered the wrong type as this was cloth sleeved PVC which I found a PITA to strip. It looks a bit of a dogs breakfast combined with the regular wiring on the power supply. Lesson learnt...

    Fired up today without issue and so far I'm gelling with it and it's giving me the sweet clean I was after.

    I need to complete the faceplate which I make myself using an inkjet printer on adhesive aluminium sheets and then connect the 240V neon.

    I've got to decide on a speaker then build a cab.

    Here's a few pics of the build process.

    Regards Lindsay,

    ..... and thanks for the inspiration that this forum provides.






  2. andyfromdenver

    andyfromdenver Friend of Leo's

    Dec 21, 2011
    Looks good! Looking forward to seeing the faceplate.
  3. robrob

    robrob Poster Extraordinaire Ad Free Member

    Dec 29, 2012
    United States
    That's a great looking amp. Very nice TIG welds too--that's not easy on aluminum sheet.
  4. King Fan

    King Fan Friend of Leo's

    Jan 1, 2013
    Salt Lake City
    Wow, super sano chassis and board. Excellent work! Thanks for sharing it.
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