Kevin Wood

Newbie Wammer
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About Kevin Wood

  • Rank
    Junior Wammer

Wigwam Info

  • Turn Table
    SL1210 Mk 2
  • Tone Arm & Cartridge
    Benz ACE L
  • SUT / Phono Stage
    Partridge / VSPS
  • Digital Source 1
  • DAC
  • Pre-Amp
  • Power Amp/s
    Quad 405
  • My Speakers
    Eminent LFT-8b
  • Trade Status
    I am not in the Hi-Fi trade
  1. Power supply build

    .. in fact, the innards shown here don't look any different to me: PSU.htm
  2. Power supply build

    That's what I was worried about. To be honest, what you have there will perform just as well as the regulators in the link you posted, in my view. Decent looking toroidal transformer, rectifier, reasonably generous reservoir cap and an IC regulator. I have no idea what Timestep are selling these days for a SL1210 but I can't see there being a significant improvement to be had.
  3. Power supply build

    To be honest, it's hard to see how you can improve significantly upon what you have. Have they really "come a long way" or is this marketing speak? If you have a regulated power supply already, then the job is done and you'd be better of putting time and money into other aspects of your system - or records to play on it, in my opinion. You have to remember that this supply is just powering the motor, not anything handling audio signals. The more sensitive circuitry such as the reference oscillator and the speed control PLL within the direct drive motor runs from an additional lower voltage regulated supply in the SL1210 and, as long as the power supply isn't so poor that it is causing speed stability issues I don't believe changing it will make any difference. On the other hand, if you fancy the project anyway to get yourself into constructing audio equipment, it's probably not a bad place to start out as long as you're careful to get the mains side of things right.
  4. Power supply build

    Indeed. The only real issue with the standard power supply is that, in some circumstances, the transformer can couple hum into the deck, although whilst mine used to do this, it stopped after I stripped down the deck for repair and then rebuilt it so the first thing to try might be tightening the transformer mounting screws and checking the screen is firmly located! The supply is regulated well enough at 21v inside the turntable, so simply relocating the transformer outside the turntable might be sufficient if hum is an issue. The Timestep is just an offboard 21v regulated DC supply, so it is indeed difficult to imagine how you might improve on this as a DIY effort (other than a significant improvement in cost!). If memory serves, the SL1210 needs 21v DC at a maximum current of just under 1 amp, so this is what you need to aim for in choosing a regulator.
  5. The MQA debate

    Ahh.. It's not D5D, it's "DSD". That stands for "Don't Sit Down". It has detected that the end of the CD is imminent and it's saving you the trouble of getting up again to turn it over. Oh, hang on.. that can't be right, can it?
  6. The MQA debate

    This is the thing. Most of this is down at -100db and it's going to be very difficult if not impossible to detect subjectively, so we tend to gravitate towards things that we consider to be "done right" from a technical perspective. That probably directs our biases too when listening to kit sighted. We just have different values of "done right". I probably ought to build a NOS DAC sometime to see if the fact that its implementation grates with me from a technical perspective makes it subjectively poor too. But.. to get back to the original point of this thread, MQA, if it gets adopted as the de-facto format for digital audio, forces us down the path of either using our existing technologies with somewhat less than 16 bit resolution or with lossily encoded Hi-res material through the MQA-mandated DAC and recovery filter, which neither of us would regard as "done right".
  7. The MQA debate

    No offence intended. Mine was meant humorously too but, on reflection, I can see that my choice of emoji could have been better!
  8. The MQA debate

    The thing is, if you're trying to reproduce a cello you want the harmonics that the cello generated not some harmonics that your DAC generated! If you accurately capture and reproduce the whole audio bandwidth, that's what you've done. The issue with NOS DACs is that they add noise outside the audio bandwidth that can be folded back into the audio range as intermodulation products. These would otherwise have been removed by the oversampling filter (or shifted so high in frequency by oversampling that they can be trivially removed by analogue filtering). I've done very little subjective testing of DACs (one of the side-effects of having something settled as "done right" in your mind is that you don't bother) so I'm not really able to comment there except that dacs like the Audio Note might well be generating some euphonic distortion in their valve output stages which can make acoustic music sound subjectively nice while making more complex stuff sound muddled, in my experience. .. apologies to BatteredHaggis for the use of italics.
  9. The MQA debate

    Fair enough - we have digressed but hopefully in doing so we have also debunked some of the claims that MQA make. Again, I reiterate that most of the intricacies of digital systems are talking about effects that will be masked by noise and other distortions in the analogue stages of a system anyway - so they aren't really worth getting too worried about. If your setup works for you in your system, that's fine.
  10. The MQA debate

    I wouldn't dispute that claim based on the measurements he's presented. It shows a nice low noise floor and low distortion products from the test signals he's presented. It's a lot more money and faff than I'd be prepared to shell out for a DAC, but you can't argue that it's competent with the test signals in his first post. He then goes on to present measurements made with dirac impulses as the test signal, and demonstrates a 50ns rise time at the output. This might be an impressive achievement had he been designing an oscilloscope or a video amplifier but it's completely irrelevant to the reproduction of music. There is no way to get such a signal into your source material unless you have violated the Shannon-Nyquist theorem and failed to band limit your analogue signal before digitising it. What effect such a signal has on your recovery filter (if you have one!) is therefore irrelevant. The XIPH videos linked above demonstrate how important a good recovery filter in your DAC is in recovering the original analogue signal from the series of impulses that represent it in the digital domain, including maintaining the fine temporal resolution, at basic Redbook 16/44.1, that MQA claim is only preserved with their proprietary system. I just fail to understand why you wouldn't want a nice linear phase, pretty much ideal recovery filter implemented in the digital domain followed by a gentle analogue filter post-DAC to tidy up any spurii well above the audio band. You can get this all implemented in a single DAC chip costing a few pounds.
  11. The MQA debate

    I've read a few articles there but I'm not a regular. His choice of colour scheme causes a bit of "transient smearing" to my eyes but he talks a lot of sense. I'll read more.
  12. The MQA debate

    Probably the "Digital Media Primer for Geeks?". Both videos and also wiki discussion of the topics are here: The above is quite a nice introduction to how digital audio works, and it then goes on to talk about digital video for those so inclined.
  13. The MQA debate

    I think this might be the video I was originally looking for:
  14. The MQA debate

    What you do have to remember with digital audio is that the impairments we talk about would be buried under the noise floor in any domestic (or professional, for that matter) analogue system! Most of it was settled 20+ years ago and the obstacles and stumbling blocks you speak of are the likes of MQA and many others desperately trying to invent some problem for which their latest product is a unique solution. I'm sorry you haven't found satisfaction with digital audio. The significant problems with it are, in my experience, in the way a lot of material is mastered, and there the damage is done before our playback systems can do anything with it.
  15. The MQA debate

    I'm sure I've read somewhere in the MQA marketing speak that it "goes beyond Shannon Nyquist". Pull the other one! I have in mind a video I've seen before that's a great into to digital audio and which debunks a lot of the myths. I can't find it at the moment but I did find this rather old and poor quality video by one of my old college lecturers which covers the subject. It gets a bit bogged down on things like jitter for a while but he does deal with subjects like oversampling and analogue versus digital recovery filters at about the 30 minute point and the first section is a good introduction to digital audio. You have to remember it's 22 years old, but the theories haven't changed! :