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Building a HackerNAP

Discussion in 'reference' started by hacker, Aug 25, 2012.

  1. Strictly Stereo

    Strictly Stereo Trade: Strictly Stereo

  2. keithsnaim

    keithsnaim Gone Fishing

    Tony !. With so many Hacker builds about to begin, can this thread go in the Reference section please.

    Regards Keith
  3. Bemused

    Bemused What's this all about then?

    You best pm TonyL Keith
    Tony pretty much leaves us alone and seldom calls in
  4. keithsnaim

    keithsnaim Gone Fishing

    Thanks for the pointer Tony.
  5. keithsnaim

    keithsnaim Gone Fishing

    I have asked TonyL if it can be made sticky or put in the reference section.

    Best Keith
  6. Tony L

    Tony L Administrator

    Thanks Keith, looks like a prime candidate for a reference room thread what with all the excellent pics 'n' stuff. The only downside is it now becomes read-only. I can easily make one / more of you a FAQ owner if it needs any maintaining, just drop me a PM.
  7. hacker

    hacker Delicious and nutritious

    Hi all,

    I've posted updated an BOM (v1.7).

    C2: Changed 47uF feedback cap to 68uF.
    C10, C12: Now omit these parts completely.
    C5, C6, C7, C8, C9, C11: Changed from 100uF electrolytic to 2u2 film

    I've also added 2 new workbooks to the spreadsheet, one for front-end PSU and one for the output stage PSU. You'll find links to Qspeed diodes, kendeil caps, etc.

    Build manual PDF: http://hackernap.com/docs/Build Manual v1.2.pdf
    BOM v1.7 PDF: http://hackernap.com/docs/HackerNAP BOM.pdf
    BOM v1.7 Excel: http://hackernap.com/docs/HackerNAP BOM.xls
    All HackerNAP/HackerCAP related files: https://www.box.com/s/jnasoijb2gg7mopasbuo

  8. hacker

    hacker Delicious and nutritious

    Thanks Martin.

    Folks, I've updated the build manual and connection diagram. Nothing major, just reflected a preference for 42-0-42 front-end and added some more pictures.

  9. Jo Sharp

    Jo Sharp Pulls on doors marked push

    Further updated advice from Hacker (in this thread http://www.pinkfishmedia.net/forum/showthread.php?t=151178):

    So yes, the single best thing you can do at present is ditch the film feedback cap (heresy!!) for a wet tant.

    Feedback cap (C2)
    Tantalum, axial, wet, at least 68uF. Voltage not important, there's only a couple of mV across it. Do this if you do anything, it's the best upgrade I've made to my amps. In fact I'd go as far as saying: do not put film feedback caps into a HackerNAP. Period!

    C13 and C14 - Output transistor decoupling caps
    If you can find them and make them fit (definitely not a drop-in mod!), remove the 470uF output decoupling caps (C13/C14) and replace them with 22uF - 68uF polyester film caps rated for 63V+. The difference this makes to bass clarity is very worthwhile. I used obsolete/unobtanium 47uF/63V Evox Rifa MMK for this.

    John Luckins' VBE mod
    I'm too lazy to link to it, but this is a great mod that vastly improves (reduces) the output impedance of the front-end VBE filter, which in turn improves bass response.

    HackerCAP - Output stage
    Ditch the inductors and use chunky wire links instead. This keeps the output imepedance as low as possible. Only do this to the output stage HackerCAPs, not the front-end ones; those should remain heavily filtered with CRCRC.

    C25 - CCS filtering cap
    There's approximately 25V across this cap, which opens up the possibilities for higher capacitance. I moved to a 10uF/50V Wima MKS2, which just drops in.

    Getting silly - wanky caps
    The front-end power rails benefit from the very best decoupling caps you can find/afford. Currently I use brass cased 1uF polystyrene NOS Russian caps at C19 and C11. These are rarer than rocking horse shit but a bargain if you can find them on eBay, etc.

    Also worth doing is the input cap. I use the obsolete/unavailble Evox Rifa SMR polyphenylsulphide caps. You could usefully use a polypropylene type here, although good luck getting it to fit on the PCB.

    This list is based on order of preference, first to last. Every suggestion except the wanky caps is something I would consider a "must do" mod. The fancy caps are really just like the salt and pepper - flavour according to taste. The rest of the changes make a fundamental difference that shouldn't be missed.

    There are more changes in the works. For example, John Luckins has been working on a hot-rodded SuperReg arrangement for the front-end supplies. I fully expect this to be another "must do" mod.

  10. hacker

    hacker Delicious and nutritious

  11. Jo Sharp

    Jo Sharp Pulls on doors marked push

    Whilst looking for useful information to add to the reference room thread, I noticed the posts about the correct orientation of the ZTX753 transistor.

    This diagram from the datasheet shows that the collector is on the left side when viewing with the curved/flat towards you:


    from the hackernap schematic:


    we can see that the emitter of the 753 connects to the power rail and top end of R28; the collector to C4. From this it is possible to establish the correct orientation, which is that the large flat side of the 753 matches the flat side of the symbol on the PCB.
  12. Jo Sharp

    Jo Sharp Pulls on doors marked push

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