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Building a pre amp and power amp

Discussion in 'd.i.y.' started by Barry, Sep 10, 2019.

  1. Barry

    Barry Member

    i have bought a lp12 with a Acos arm and Supex gst 801. Now I need a amp so I’m looking for suggestions and advice on what to buy. I’m a ex RAF electronics fitter and I have very good soldering skills.
    So any advice will be considered carefully
    Barry ( I’m new to this forum)
  2. Vinny

    Vinny pfm Member

    Welcome Barry

    Well, the world is your oyster really but the first question has to be , how much £££ do you have to spend, and what else do you want the amp' to accept - CD, tuner, etc.?
    Also, are you sure that the Supex is working and in good condition? It is a very old cart' but that does not mean that it is necessarily anything but absolutely fine (although I can find no mention of it online......). If the Supex is fine and you are happy to keep it, it complicates things slightly as it will affect what phono stage you will need, be that stand-alone or on-board the amp'.

    You will get a deluge shortly :)
  3. bugbear

    bugbear pfm Member

    * you'll need a phono amp, a pre-amp and a power amp

    * many pre-amps include a phono stage.

    * many power amps include a pre-amp :)

  4. davidjt

    davidjt pfm Member

    Have you looked at the DIYaudio forum? Many options there.

    Also a few on Hi-Fi Collective - hificollective.co.uk

    Your choice of type/size/format of loudspeaker will narrow things down.
  5. Marra

    Marra pfm Member

    As mentioned lots of choice on diyaudio in particular the Nelson Pass First Watt designs in particular the M2 power amp. Couple it with a Salas DCB1 buffer volume control stage or if you need gain the Salas DCG3 pre/headphone amp.If you fancy a modern take on tubes the Nelson Pass B1 Korg Nutube pre; loads of gain with a sound stage to die for.
    For single ended class A check out Colin Wonfors' for his SECA power amps. I think he still does boards.
  6. 337alant

    337alant Negatively Biased

    Hi Barry and welcome to PFM
    The Avondale audio NCC200 or NCC220 are very good power amplifier boards just build a power supply and you have a seriously good amplifier
    There are plenty of threads on here about building from scratch or alternately you can buy amp boards and cap6 rectifier filter boards ready built just add a transformer
    Give Les Wolstenholme a ring and discuss what you want
    I am using His NCC 300 mono blocks and they are also excellent
    For a pre amp I am using 2 of Les's 821A pre amp boards with a TPR4 regulator board, transformer regulation and smoothing caps, a 6 way switch for multiple inputs and a Volume control
    821A pre amp
    [​IMG]IMG_2036 by Alan Towell, on Flickr

    NCC 200 Voyager mono amp

    [​IMG]voyager 14 by Alan Towell, on Flickr

  7. Matty297

    Matty297 pfm Member

    Last edited: Sep 11, 2019
  8. chiily

    chiily PFM Special Builder

    Hi Barry,

    Another couple of pre-amps to try are the B4 from PD on here https://www.pinkfishmedia.net/forum/threads/b4-pre-amp.107753/ or something like the DIY Audio's Whammy https://www.diyaudio.com/forums/pass-labs/317803-whammy-pass-diy-headphone-amp-guide.html a headphone amp that can be quickly turned into a pre-amp.

    [​IMG]20160416_213845 by Garf Arf, on Flickr

    [​IMG]IMG_20190320_202203 by Garf Arf, on Flickr

    For power amps, I have to agree with Alan above, Les W makes some exceedingly nice amps.

    [​IMG]DSCF5875 by Garf Arf, on Flickr

    Sadly, I just can't build 'em neat!!
  9. davidjt

    davidjt pfm Member

    Looks pretty good to me. I might tidy up the transformer wiring just a tad - otoh I might just case it up, forget about it and enjoy the music. :D

    Reading the 'silver capacitors' thread has just spoiled my day, though. The very best capacitors are £200 a pop. Full range speakers and amps with no caps in the signal path seem to be the only option for us OAPs.
  10. Barry

    Barry Member

    Thanks for the replies, I’m still looking but I’m taking all advice my new(old) LP12 will be with me in a day or two so I can see exactly what I have to do to get it 100%. I’m up for a diy project for sure
    I can’t find a reference to silver caps, can someone point me in the right direction. Why are expensive silver caps needed? There’s plenty of others out there.
  11. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Don't worry, bog standard caps are perfectly good enough.
    Julf likes this.
  12. Barry

    Barry Member

    Thanks, apart from working voltage and maybe leakage I couldn’t see why they might show a large, if any, difference to sound quality
  13. Jeff Young

    Jeff Young pfm Member

  14. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Good link.

    I've done listening tests between various caps at line level (as coupling caps) and any differences were at the "am I imagining that or not?" type level.

    However.... I have found very marked differences between dielectrics in sound quality terms in a very few specific places where a capacitor is called for.
  15. Barry

    Barry Member

    Good Article! Makes perfect sense to me. Obviously silver caps have their use but certainly not in my project. Being a OAP I have to build my amp(s) for the cost of one of those .


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