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"You ain't heard nothin' 'til it's modded!" ;-)

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spindrifter

In Reply to: RE: VALAB DAC any tweaks yet? posted by magicsam on February 19, 2009 at 05:49:14

FYI, I replaced cheap, unsuitable Russian PIO caps as their early coupling function in the circuit demands better frequency linearity (top to bottom) - I slotted in 0.01uf ERO metallized polypropylene and foil instead. Crucially original totally-inappropriate tantalum output signal couplers were replaced by 2.2uf BC orange drop MKT (owing to severe space retrictions, would have preferred premium foil caps.) But once run in those BC MKTs are not too shabby at all!

I also installed Sanyo OSCON digital decouplers, Panasonic FM main DC reservoir caps, Cardas RCA chassis sockets and upgraded internal wiring etc etc. Undoubtedly worth the effort. These mods transform the DAC's sonic performance. Sounds more like analogue than digital.

BTW Mr Valab advertises his DAC contains 470uf Nippon Chemicon PSC solid aluminium polymer electrolytics. Well, it actually comes supplied with cheaper 330uf Nichicon electro's. In any case that capacitance value is overkill. Suggest you replace all those with 100uf 20V Sanyo OS-CONs for remarkable sonic improvement!

Trust this helps. Happy listening! ;-)

spindrifter

Follow Ups:

RE: "You ain't heard nothin' 'til it's modded!" ;-) - magicsam 11:44:37 02/20/09 (3)
Thanks spindrifter!
I'm new to this tweaking.
Will the following be enough/right stuff to do the job?
8pcs 100uf 20v Sanyo Os-Con SA Radial Capacitors
10 ERO Roederstein 0.01uf 630v KP1838 PP film + foil
14 Philips MKT 2.2uF 250V Poly Metallized Capacitors
- Not quite........ - spindrifter 23:18:46 02/20/09 (2)
  magicSam
  
  While I wouldn't like to discourage anyone from "having a go", this is not an easy project, the equivalent of micro-surgery in a tightly restricted space, fraught with dangers such as static discharge. And if you make even one slight mistake, you'll end up with sparks, smoke 'n tears. :-(
  
  So the usual DIY disclaimers apply - you do so entirely at your own risk. Do you have health insurance and a fire extinguisher?
  
  You'll need -
  
  Skills - steady hand, acute eyesight, the patience of Jobe, basic knowledge of circuits.
  
  Tools/materials - Stable work bench. Small vise. Bright light. Magnifier glass. Pro solder station with adjustable temp and fine round bit. Highest quality silver solder. Solder sucker or wick. Small Dremel drill with selection of micro bits. Set of electronics picks. Various screwdrivers, small accurate cutters, small needle nose pliers, small adjustable wrench. DMM. Wire stripper.
  
  Parts - Cardas RCA GRFA short (thin nut) chassis sockets x 2.
  15 cm 24/26AWG silver plated PC-OCC signal wire teflon insulated (or equivalent).
  8 pcs 100uf 20v Sanyo Os-Con SA Radial Capacitors
  1 pc Panasonic FM 100uf 50V radial cap or equivalent (e.g., Rubycon ZL)
  3 pcs Panasonic FM 1000uf 35V radial caps
  2 pcs ERO Roederstein 0.01uf 630v KP1838 PP film + foil caps
  2 pcs Philips MKT 2.2uF 250V Poly Metallized caps (if they fit - check dimensions and lead type for that particular cap series - longest dimension must be less than 23mm)
  2 pcs Evox MMK 0.47uf 63V radial box caps (or equivalent, 7.5mm pitch)
  
  You might also require a couple of replacement 3mm LEDs and matching load resistors as Mr Valab's cheap LEDs tend to disintegrate once you open the case.
  
  That's about it. Best of luck. Hope it all works out for you.
  
  spindrifter
  
  PS - BTW the modded DAC really benefits from the use of a premium power cord.
  - RE: Not quite........ - magicsam 11:41:04 02/23/09 (1)
    Thanks!
    Turning this over to my friend the electronics engineer.
    What's the single biggest and easiest improvement?
    - Chain only as strong as its weakest link...... - spindrifter 23:56:44 02/23/09 (0)
      Your engineer friend may discover further upgrade options that put mine in the shade. Whenever I assess, plan and implement a project it's either done properly or forget about it. Kind of like listening to music constantly irritated/frustrated that sonics aren't optimal. Why bother?
      
      spindrifter

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