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  1. mwofsi

    'noodle' dac (ebay special)

    Quote: Greater than 0dB means it is amplified Oops, thankyou error401. EDIT:If I knew what I was talking about I should have said 3dB decrease is double the ripple rejection that went before. Editted Edit: And ripple rejection can also be expressed in other figures, more being the aim.
  2. mwofsi

    'noodle' dac (ebay special)

    gurusan, if you haven't already check your power supply by ensuring there's no short between the 12-0-12 inputs. If thats ok set up a resistor divider and connect a 9V batterry (less risk than using your 12V wallwart) to the supply. As long as the ground/0 position corresponds it won't matter...
  3. mwofsi

    'noodle' dac (ebay special)

    Quote: I was looking at the LM1086CT-5.0...and it says: Well we're well out of my league here, but looking at the data sheet they're not pin compatible. That is the input/output pins aren't in the same place. Also, I think you'll find that the Ripple Rejection/Supply Voltage...
  4. mwofsi

    Newbie Q, advantages of diy DAC

    Quote: DIY' (ing) is a very expensive hobby, and I think many people make the mistake of approaching this hobby, with their primary motivation being "to save money". Completely agree. I've spent a lot more than I expected. Definitely not 'having a go' btw Tom B., your efforts and...
  5. mwofsi

    'noodle' dac (ebay special)

    Quote: Originally Posted by ls206 It's a shame there's literally no diy audio on ebay UK One gets used to it. Don't think I've had anything of this size/cost fom HK, but I've gotten smaller items. Taiwan as well, also similar and larger items from America. It's all usually...
  6. mwofsi

    'noodle' dac (ebay special)

    Quote: Originally Posted by ls206 is this DAC imported? the only kits I could find are from HK Yes, that's correct
  7. mwofsi

    Problems With An Ori Modded Zhaolu 2.5A. Anyone Have An Original Schematic?

    I'm not sure that it's fair to Ori to give out all the details. It's not as though I've worked out the circuit completely anyway. There seems nothing fancy about it. I believe that it is advertised as an all discreet output stage. What it does do is convert differential dac signals to single...
  8. mwofsi

    Problems With An Ori Modded Zhaolu 2.5A. Anyone Have An Original Schematic?

    I have an Oritek modded Zhaolu, bought at a time when I didn't even want to open a dac let alone mod one. I wanted a solution that people were happy with and this seemed to fit the bill. It is not producing sound other than slight background hiss. It'd been in daily use for 8 months or so...
  9. mwofsi

    CS4397 DAC - Output Stage layout. Advice sought and comments welcome

    00940, How about a dc opamp servo, to get rid of the output cap. I couldn't figure out how to do it? Is the separate output stage just there to produce the right level or does it serve other purposes such as lower distortion and/or crosstalk?
  10. mwofsi

    CS4397 DAC - Output Stage layout. Advice sought and comments welcome

    Quote: Originally Posted by majkel No, for unbalanced you need to connect the analog ground to your amp's and the + analog output of the DAC coupled via the capacitor to the amp's input. For balanced you use both + and - outputs, in some cases even without capacitors (if common mode...
  11. mwofsi

    CS4397 DAC - Output Stage layout. Advice sought and comments welcome

    Quote: Guys, has anybody compared signal coming out of this discrete buffer to the direct coupling of L/R+ DAC outputs Interesting point majkel. Wouldn't that require a balanced amp and headphones? If the join was before that wouldn't the dacs outputs be shorted? One could of course...
  12. mwofsi

    Cambridge DACMagic, anyone?

    Has anyone got any internal pictures, or links to them? Might be an interesting basis for modding if they're not awesome to start with?
  13. mwofsi

    CS4397 DAC - Output Stage layout. Advice sought and comments welcome

    Hello fordgtlover, hadn't read this thread before, and I too have become interested in the noodle/lampucera dac. Also, I know nothing (and what little I learn I forget). In the circuit diagram in your first post you have Q2 as a darlington? This isn't the case in Leo's diagram in the first...
  14. mwofsi

    Good source for inexpensive braided shielding?

    I'm curious about this too. Seems an obvious extension of diy to choose your own internal cables and a simple shield.
  15. mwofsi

    SOHA II - Super SE Hybrid

    Can I ask a couple of power supply design questions (this isn't about the SOHA II, it's more to improve my comprehension) ? What roll does the size of caps in the voltage doubler play? Presumably too small and they'd be fully charged before each phase change? Can they be too large? Do they...
  16. mwofsi

    Post pics of your builds....

    Stereo buffers on a protoboard. Simple stuff with BD139/140 outputs and diode biasing. There is an attempt at a DC offset servo in between. Can you spot the deliberate mistake(!) in this pic? Anyway tried it out as a Soha (mk 1) buffer and it sounds pretty good, quite bright but not...
  17. mwofsi

    Twisted Pear Buffalo Sabre DAC

    They do not look good do they? You could try pressing down on the pins gently with a cocktail stick while listening to see if that confirms a problem.
  18. mwofsi

    SOHA II - Super SE Hybrid

    I'm not in the market but I think those panels are excellent. Very classy, cohesive (had to look that up in a thesaurus!) and professional.
  19. mwofsi

    7-pin zip package (2SJ109, 2SK389)

    Quote: Originally Posted by suds07 Where is the file ? It's an old post, from 2006. As the file doesn't seem to have been added as an attachment the file has probably been deleted/lost from it's host. There was also a HeadFi server problem/crash a while back which messed up a lot...
  20. mwofsi

    Getting started: internal wire, power cable, connectors, casing help please!

    Quote: 1. Internal wiring Suggestions? good size (AWG)? ..... .... When wiring between components, any good rules to follow? I figure signal-bearing wires should be twisted pair, while fluctuating high-power lines should be isolated. I've seen 22awg recomended as a good useful size...
  21. mwofsi

    Zero DAC noise in left channel

    It should also be possible using similar techniques to replace the supplied socket/plug with a shop bought header and socket/terminals. It's quite awkward to get a good crimp of those terminals onto a wire even with a proper crimping tool. Industrial crimping tool versions probably have a higher...
  22. mwofsi

    Zero DAC noise in left channel

    In that case it's probably time to brush up on your desolder technique. Remove with desolder braid as much solder as you can from each of the four pins before gently wiggling and trying to remove the socket as you pass your iron over each of the pins in turn. Else cut into the socket with an...
  23. mwofsi

    Zero DAC noise in left channel

    Nice pictures and well done on the fault finding. The white part that the red and white wires run into is probably a socket. It may be possible to remove it from the board in order to repair it. It may have some form of latching mechanism holding it to the board, it might be friction or it...
  24. mwofsi

    Getting started: internal wire, power cable, connectors, casing help please!

    Ok, I'll take a guess at 3: Torroids have a lower magnetic stray field, any deficiencies they have regards to passing high frequency mains noise have been taken care of in the design of the Twisted's power supplies. They're readily available in reasonable qualities and their lighter weight...
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