Jump to content


  • Content Count

  • Joined

  • Last visited

  • Days Won


Shadders last won the day on March 21 2019

Shadders had the most liked content!

Community Reputation

250 Excellent

About Shadders

  • Rank
    Experienced Wammer

Wigwam Info

  • Turn Table
  • Tone Arm & Cartridge
  • SUT / Phono Stage
  • Digital Source 1
    Dune HD Base 3D
  • DAC
    Audiolab 8200AP
  • Integrated Amp
    CambAudio Azur 650
  • My Speakers
    DIY Transmission Lin
  • Trade Status
    I am not in the Hi-Fi trade

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. Hi, On the DIY Audio store, there is a chance to purchase a Sony VFET amplifier kit for $499. Apparently, although this was announced on 2nd April 2021, and the thread is 1st April 2021, it is a true offer. https://diyaudiostore.com/pages/vfet-information-page There is another forum where people have been relieved of £2k for a VFET amplifier that does not exist after 7+ years. As such, here is an opportunity to own one at 1/4 of the cost (including chassis and parts etc) Regards. Shadders.
  2. Hi, Keep the CD's and don't sell. Despite it being illegal, if your hard disk(s) suddenly fail then you have nothing. Regards, Shadders.
  3. Hi, Here is a quote from Issac Asimov which can be transferred to Hifi : “There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.” From (https://www.goodreads.com/quotes/456687-there-is-a-cult-of-ignorance-in-the-united-states) Regards, Shadders.
  4. Hi, The circuit is essentially as per the example design in Doug Self's Active Filter book - i changed a few things, but the basics are there. For ADC's and DAC's, i don't have the specific circuit diagrams, but some DSP books and literature on the internet describe the structure. I never stated you can create a circuit that is a wire with gain. The low levels of distortion available from some amplifiers do go quite some way to achieve this though. I am interested in audible distortion that cannot be measured - do you have links to the articles ?. Thanks. In my c
  5. Hi, No one stated predicting sound quality was possible. Regards, Shadders.
  6. Hi, Yes, people do like distortion. Nothing wrong in that. The point is, the measurements used today are more than enough to characterise an amplifier. There are, no unknowns in regards to amplifiers and how they sound to the human. The problem is that people are different, so one cannot state an amplifier will sound x, y or z to a human, but we do know why it sounds like x, y, or z. The arguments on amplifier sound is really futile, as the Bob Carver experiment proves amplifiers do sound different, and the objective measurements have proved that. Regards, Shadders.
  7. Hi, I can see the logic that more components will degrade the sound, and this is true - if they are sub-optimal. The TL072 opamp is an old design and there are much better performing opamps as per the 1980's NE5532, and lately the LM4562. I posted on another thread that Bob Carver solved the sound characteristic heard in an amplifier, which is determined by the amplifiers distortion profile. It does not matter how many transistors there are in the path, but what does matter is the distortion profile. In this thread i have seen references to analogue crossovers, which i have not
  8. Hi, For amplifiers, it has been solved, and probably applies to DAC's too. Bob Carver solved this in the 1980's - they used a generic cheap amplifier, and using his engineering skills modified the generic amplifier distortion profile to be the same as another amplifier, and the reviewers (Stereophile) could not determine the difference. Please see : https://en.wikipedia.org/wiki/Bob_Carver Amplifier modelling section has the details. The current measurements are sufficient, else Bob Carver would not have been able to emulate another amplifier using 1980's technology. R
  9. Hi, Wadia used to make their own DAC's which were near discrete, but the DI322 uses the ESS DAC IC, and Chord use an FPGA DAC, which is essentially PWM (from memory, Hifi News review). For the Wadia Di322, which uses the ESS Sabre 9016S DAC IC, the IC can achieve a S/N 128dB, but the Wadia implementation reduces this to 110dB. So Wadia have done something to reduce the performance. For the Chord using PWM implemented in an FPGA, this is a proprietary design, and therefore the signal processing can affect the output significantly even though there is a flat spectrum. Other tests
  10. Hi, Yes, you can. https://www.maximintegrated.com/en/products/analog/audio/MAX9709.html Regards, Shadders.
  11. Hi, I disagree. The PWM signal transition from positive to negative is not discrete in the time domain. If the PWM transition was discrete in the time domain, then it could be considered a digital conversion in the time domain. Regards, Shadders.
  12. Hi, No, there is no ADC in most class D designs, it is a comparison between the input audio signal and sawtooth waveform that translates to the PWM signal. EDIT : You could interpret that the conversion/translation process is a 1bit modulator- which is used by ADC's. Regards, Shadders.
  13. Hi, The crossover and bandwidth limitation of the driver only reproduces the sound relevant for the driver. They are a filter in themselves (obviously for a crossover) - the PWM signal although bipolar and rectangular, mathematically contains the audio signal. Regards, Shadders.
  14. Hi, The "conversion" is just a simple LC 2nd order filter. You literally are listening to a rectangular wave passed through a coil of wire before it gets to your speakers. If you omitted the coil you would still hear the sound, but with increased noise. It may affect your tweeter or midrange detrimentally and permanently, but the crossover will deal with most of the energy. There are class D designs such as lowish power chip amps that use no output inductor and connect direct to the speaker. Regards, Shadders.
  15. Breasts and speakers come in pairs, so why not DAC's ?
  • Create New...