1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Scratch Build – In Progress DIY Hifi

Discussion in 'Project Logs' started by Margo Baggins, 24 Mar 2017.

  1. Margo Baggins

    Margo Baggins I'm good at Soldering Super Moderator

    Joined:
    28 May 2010
    Posts:
    5,650
    Likes Received:
    268
    I decided to do away with traditional sound cards as I couldn't bare the noise present on just about every single sound card I ever tried, So I built myself a DAC. When I built the DAC, I wasn't happy with the headphone amp so I built a head phone amp. Then to see if I could I built myself a power amp. Now I'm working on the pre-amp which I should finish sometime before summer 2017.

    Margo's Mods - DAC1

    Modified completed DAC mainboard - as the board is quite small, I moved all the parts for the power supply off the board and built my own power supply. Digital supply I left on the board, because, well, who cares about digital :)

    [​IMG]

    Some stuff didn't fit on the top as I used different parts to what the PC wanted, so I put some stuff on the bottom and used some tall standoffs

    [​IMG]

    Fancy caps to decouple the opamp.

    These are discrete regulators which have just about zero measurable noise, vs traditional regulators which have some noise.

    [​IMG]

    This is the powersupply I built using the regulators. There is 22,000uf of filtering on the +/-15v supply which powers the opamp, there is also +5v which powers the analogue side of the DAC chip.

    [​IMG]

    Boxed up in a nice chinese aluminium box

    [​IMG]

    The opamp in there was just for testing, and I didn't want to put the hideously expensive discrete opamp in until I knew everything was working

    Complete with the discrete opamp

    [​IMG]

    The initial idea, before I decided i wanted to build my entire own hifi, was to build a decent sounding DAC for less than I could have bought one for. Originally this DAC was not supposed to cost very much money.... it ended up costing me about £350, but, it is AMAZING. I don't have the facility to measure anything scientific, but there is zero noise that I can hear with this unit. I can fully turn up the volume on an amp, and hear nothing at all.

    Album is here - http://imgur.com/a/Rmp5S
     
  2. Margo Baggins

    Margo Baggins I'm good at Soldering Super Moderator

    Joined:
    28 May 2010
    Posts:
    5,650
    Likes Received:
    268
    Margo's Mods Amp1
    Album is here - http://imgur.com/a/ODUTz

    Next I built a headphone amp, to power my headphones

    Some ludicrously expensive caps from Hifi collective - resistors that cost 40p each, it's like shopping in maplins hehe except all the stuff is really good.

    [​IMG]

    This project is based on the lehmann headphone amp - however, I used the parts I wanted to use and not what the project dictated. Board partially completed.

    [​IMG]

    Board fully completed

    [​IMG]

    Boxed up in a nice chinese aluminium box, massive input caps make the bass big and deep

    [​IMG]

    set up with the DAC, this is how I listen to music and games now on my PC

    [​IMG]

    The usb -> spdif I didn't make, because I managed to get this nice gold asynchronous one for only £25 which was a real bargain.

    This setup has no noise. Whatever volume you listen to music or games, you do not hear anything other than the sound created, it's wonderful.

    Again this was supposed to be cheap, but it ended up costing me about £200. I want to put a discrete opamp in it but I haven't been willing to buy one yet as they are so expensive.
     
    Last edited: 24 Mar 2017
  3. Margo Baggins

    Margo Baggins I'm good at Soldering Super Moderator

    Joined:
    28 May 2010
    Posts:
    5,650
    Likes Received:
    268
    Margo's Mods - Power Amp1
    Album is here - http://imgur.com/a/qJY88

    When I built this, it was the most ambitious thing I had built (but now superseded by the preamp i'm working on). And I mainly did it to see if I had learned enough and if I "Could" do it. So I mostly made it up as I went along with stuff I had read, and I nearly blew it up, so good learning all round :)

    This is one completed channel (of which there are 2, as it's a stereo amp)

    [​IMG]

    As always, I put what I wanted in the pcb and not what it called for, i'm not sure why, as I don't really know what I'm doing :)

    Sizing up the box, 1kg of heatsinks, 500g each side

    [​IMG]

    some more adjustments

    [​IMG]

    Wiring up the rectifier circuits, 60,000uf of capacitance on each side, 30,000uf pre rail. Super excessive :) Handles music peaks like they aren't peaks.

    first time I completed the unit

    [​IMG]

    However, There were a couple of things up. Once rectified the 45-0-45 was giving me 63v +/- DC, and the spec of the circuits was 60vdc max, so this is bad. Also as there is so much filtering capacitance the amp would keep playing for about 30 seconds to a minute after I turned it off. So back to the drawing board.

    Exterior

    [​IMG]

    Installed a new transformer, much bigger, less volts, gives me 45vdc once rectified, which is what I originally wanted, but as i was making it up as I went along I didn't understand what happened when you retified AC with a capacitor, now I know. Also fitted a small 12v transformer for a speaker protection relay, which also works to kill the output after the unit is turned off so it doesn't keep playing .

    [​IMG]

    Amp completed with a nice silver contact relay on the output

    [​IMG]

    This time I didn't want to scrape and do it cheap, and i went slightly nuts on the parts. cost me about £350 and is about 120ish watts per channel. It's a monster.

    As I like fancy things - the signal wire from the DAC, right through to the output of the power amp is all silver. Apparently silver is a nice conductor, it's expensive, so that's how it works right ? Weighs 14kg so it's a heavy old box.
     
    Last edited: 24 Mar 2017
  4. Margo Baggins

    Margo Baggins I'm good at Soldering Super Moderator

    Joined:
    28 May 2010
    Posts:
    5,650
    Likes Received:
    268
    Reserved for Preamp
     
  5. storm-83

    storm-83 Minimodder

    Joined:
    7 Nov 2014
    Posts:
    452
    Likes Received:
    14
    it's true what they say;
    "Bad sound kills good music!"

    Cool project! Endresult looks really nice :thumb:
    If only i knew how to solder and had any spare money :lol:
     
  6. Mister_Tad

    Mister_Tad Will work for nuts Super Moderator

    Joined:
    27 Dec 2002
    Posts:
    13,276
    Likes Received:
    1,542
    This is awesome. Have you had the opportunity to compare it to any other off the shelf DACs?

    What was the reason you opted for the extenal USB->S/PDIF box over building USB->I2S into the DAC?

    After doing a bunch of mods on my CD player, building my own DAC from a kit was always one of those things I wanted to do, but never got around to. I even went to far as to make the complete shopping list, but then, well... didn't.
     
  7. Margo Baggins

    Margo Baggins I'm good at Soldering Super Moderator

    Joined:
    28 May 2010
    Posts:
    5,650
    Likes Received:
    268
    I have no off the shelf dacs :( they were too expensive the ones I wanted which is why I built my own one! but it means I can't compare it with anything other that memories of using fancy dacs at uni.

    The reason I went with an external USB was mostly for driver support. A lot of the usb > I2S modules looked funky and I didn't want to have to use a dodgy chinese driver or not be able to find a driver down the line, I've heard I2S IS better than spdif though, and I can hack I2S onto my dac pcb if I solder straight to the pins of the chip, which I'm totally down for. I think i'm planning on doing another DAC and then butchering this one again.

    The actual kit to build the dac PCB was only 20 quid, but then I didn't use any of the parts for it and spent a ton of money on discrete parts.

    I'm fairly confident it sounds alright, it sounds better than any of my soundcards I have at home, but then the best one I have is a titanium HD, so not the best soundcard ever.
     
  8. Mister_Tad

    Mister_Tad Will work for nuts Super Moderator

    Joined:
    27 Dec 2002
    Posts:
    13,276
    Likes Received:
    1,542
    What you say RE I2S makes a lot of sense... I didn't even consider that. What a great "up yours" from the universe it would be if you built the best DAC in the world that could never be used :lol:

    I had a similar experience... you start out thinking you'll build something cheap and cheerful, and find by the time you've done all of your homework you've got a single cap on the list that costs more than the entire kit did to start with.

    I have a funny (odd, not haha) past with DACs. There's so much hyperbole kicking around the webs for a handful of "giant killer" DACs that so many communities seem to put on a pedestal, and I got sucked into one, and then another decent dac, but with unwarranted amounts of hype - this is when I decided I would build my own, but then I picked up an Arcam rPAC on a whim and it was truly excellent for the money, so stuck with that for a bit until I eventually stopped using PC audio and was DAC-less for a while. It wasn't until around a year ago that I went shopping, eventually took home the Chord DAC for an in-home demo on my main hi-fi, and ended up never giving it back.

    My door is always open if you want a DAC-off with a Chord 2Qute... I promise I won't be bitter when yours ends up sounding better :D

    I'd love to try out that power amp on my AV setup... find out what real current sounds like, as opposed to my Denon's "165 but not really" watts. That's another thing that's kind of on the to-do list, but I know I'll never get around to.
     
    Last edited: 24 Mar 2017
  9. Margo Baggins

    Margo Baggins I'm good at Soldering Super Moderator

    Joined:
    28 May 2010
    Posts:
    5,650
    Likes Received:
    268
    My receiver is 125 but not really watts per channel - and this amp is much more 120 that that's 125.

    Unfortunately I bought my receiver just before I started doing all this, and it's a fairly decent unit but it doesn't have preamp out :( As I don't really have space for multiple hifis, the big ultimate game plan is to get a different receiver, like a Marantz one, and then build amps and use the receiver just as a pre, I think that would me terrific.

    It just all costs so much time and money. and having a real life to contend with means it's taken me about 18 months to get this far!

    when I get my other dac made i'll ship you this one to play with

    All that being said - I'm still not brave enough to plug my DIY amp into my Dali speakers. As if it blew them up i'd probably cry, as they were 650 quid. Which maybe in the world of hifi isn't that much, but it took me a long old time to decide to actually spend that kind of money on some speakers!
     
  10. Trance

    Trance Two steps forward, one step back

    Joined:
    6 May 2009
    Posts:
    618
    Likes Received:
    32
    Nice few projects, the amount you spent on the caps and resistors makes me wince a bit, to be honest the entirety of hifi collective makes me wince!

    Looking to do a project of my own along these lines if I ever manage to get out the design phase, damn my desire to design from scratch!

    Don't think I've ever seen so much DC filtering on a DAC, overkill to the extreme!
     
  11. Vault-Tec

    Vault-Tec Green Plastic Watering Can

    Joined:
    30 Aug 2015
    Posts:
    12,341
    Likes Received:
    2,095
    Damn you. I've been wanting to build myself a headphone amp for what feels like forever.

    I *had (*past tense) a LD MK2 being used as a pre amp with the output going into my Graham Slee Novo. I had found paradise. The mixture of the valves to flavour the sound ever so slightly and add the warmth I like was just awesome, and the honesty of the GS made sure it sounded fantastic.

    Then the LD MK2 died and was the fourth LD I have had die the same death. Sound cuts out from one channel, wiggle the valve around sound works but stops when you let go. Poor soldering no doubt..

    So now I am basically looking to build myself a valve based pre amp. Been looking at kits just yesterday on the bay.
     
  12. Margo Baggins

    Margo Baggins I'm good at Soldering Super Moderator

    Joined:
    28 May 2010
    Posts:
    5,650
    Likes Received:
    268
    Yeah the prices are bonkers for some of the stuff. I don't mind so much, If I'm going to spend the time making something I like to put in it the best I can afford, similar to PC building. I'm not going to harp on about snake oil, but permium parts are closer in spec, and they last longer in my experience.

    At the same time - I cheaped out on the big caps, and they aren't all from hifi collective. 120,000uf of capacitance for Hifi Collective is about £160 quid with tax, and, well that's too much!

    Ebay kits are good but sometimes the parts are a little crappy, but the circuit boards are normally good. I haven't done any valve stuff, or even really heard valve stuff beyond an old valve receiver I have. The whole reason I got into all this is to be able to one day be good enough to sort it out, needs to be completely recapped and it's point to point and most of the wiring needs to be redone. That will be a project for 2018 I hope.

    i do know from people i've talked to - most of the chinese valves aren't that good, so it's better to source them from elsewhere. American or Russain valves seem to be what people like.
     
  13. Vault-Tec

    Vault-Tec Green Plastic Watering Can

    Joined:
    30 Aug 2015
    Posts:
    12,341
    Likes Received:
    2,095
    You've built some beautiful stuff man. I kinda dived deep into head-fi last year and bought a few too many pairs of headphones. Thing is, I've come to the conclusion that I love valve amps. I tried a few reasonably high end amps that are totally neutral but I just find it all a bit cold.

    I don't need anything crazy. Been checking out kits today, range from like £11 to £100. I only need the pre stage too. I initially ordered a LD MK1 and absolutely loved it. It has valve pre/regular amp stages. When it died I thought I would go the extra mile and order the LD MK2 as surely it was better.. Well it's all valve and it just didn't have the guts to drive a couple of pairs of my cans (Hifiman and Musical Fidelity). So yeah, I ended up running the pre out into the Graham Slee, perfect, until it died.

    I think I have everything I need in my basket now. Really want to use burred walnut for the top of it, or something I can really make shine. Even something like a Little Bear will do. Doesn't need to be huge, just have that valve pre stage :)
     
  14. Margo Baggins

    Margo Baggins I'm good at Soldering Super Moderator

    Joined:
    28 May 2010
    Posts:
    5,650
    Likes Received:
    268
    Maybe i will build a valve pre. The preamp I'm working on at the moment is discrete, based on Marantz HDAM circuits, so no opamps which is nice. The beauty of having it as separates is it's easy enough to swap everything out.

    Just all costs so much money! haha. the 440mm enclosures, even from china, once you've got them here and paid tax, they are as good as 100 quid each.

    Thanks for the kind words though :)

    I've accidentally picked up a few sets of headphones. My favourites though are DT-770 250 ohm. Which aren't massively expensive, I was thinking about getting a set of planar cans to see if that makes much difference, but then, I prefer spending money on electronics than cans now I have found a set of cans I like.
     
  15. Vault-Tec

    Vault-Tec Green Plastic Watering Can

    Joined:
    30 Aug 2015
    Posts:
    12,341
    Likes Received:
    2,095
    I usually jump between Grado RS2E (because I always keep coming back because they're the best pair of cans I've heard, even if they are a little bassless...) my Hifiman HE400S for that big powerful sound and my B&Os. Oddly enough the Grado are the only cans I really like listening to without my valve pre. Even though the sound is very delicate the soundstage itself is just unmatched by anything.

    So if it goes well I might build myself a kit GS Novo to leave on the Grados.
     
  16. Cheapskate

    Cheapskate Insane? or just stupid?

    Joined:
    13 May 2007
    Posts:
    11,835
    Likes Received:
    1,526
    Lovely stuff. :D That bit about over capping- :lol: I'd love be able to do something like this, or just shore up my existing equip. I have a small fortune in not perfect high-end equipment. -including a stone dead amp. I took a look inside and was horrified at the tightly packed mass of wires. I kept it because it feels like throwing a car away.
    I find it ironic that my sound system upgrades as my hearing degrades. The speakers I had in high school sounded like they were buried in sand.
     

Share This Page