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Shadders

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About Shadders

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  1. Hi, It is going to happen - Microsoft have stopped access to the e-books : https://www.bbc.co.uk/news/technology-48829661 Will happen to other services and purchases, such as games etc. I always purchase the CD or DVD/Blu-ray, and have never downloaded. There will always be a glitch, dispute, or cessation of service, affecting the customers. Regards, Shadders.
  2. Hi, Farnell has the same issue - despite the transistor being in the system as i could locate it through narrowing the filter criteria, it could never return the device through a search. I noticed that when i completed a search, then "bing" was in the search URL that flashed up. Maybe the target system has moved across to a Microsoft solution ? Regards, Shadders.
  3. Hi, @The Computer Audiophile , if possible, can you move the relevant posts from #15088 onwards, in this thread to the new one created : Thanks and regards, Shadders.
  4. This is the discussion on whether Red Book CD (RBCD) is all we need fro audio reproduction given that amplifiers may or may not have a lower noise floor.
  5. Hi, Not sure how he calculated - the Rane article states : Required Conditions. In order for the published figure to have any meaning, it must include the measurement bandwidth, including any weighting filters and the reference signal level. Stating that a unit has a “S/N = 90 dB” is meaningless without knowing what the signal level is, and over what bandwidth the noise was measured. For example if one product references S/N to their maximum output level of, say, +20 dBu, and another product has the same stated 90 dB S/N, but their reference level is + 4 dBu, then the second product is, in fact, 16 dB quieter. The 130dB has to be referenced to a specific output level. The ASR review is not clear on what output signal level is being used. Regards, Shadders.
  6. Hi, If we assume 200watts in 8ohms specification for the amplifier (i think it is specified at 100watts), then 200watts is 23dB. The SPL 120dB - 23dB = 97dB sensitivity speaker. Not many speakers in that range. I quoted 86dB as this is more probable. Even a 90dB sensitivity speaker requires 1kW amplifier. Is it not the issue that, the lower sensitive speaker requires the amplifier to provide a greater power, increasing THD and hence the stated 120dB SPL etc. statement is not relevant ??? The issue is also, the 130dB figure measured - what were the parameters for this measurement ? If 1watt into 4ohms is -106dB due to THD, then how is -130dB S/N achieved in the test - what were the parameters ? I think the relevance to MQA here is that the noise floor of CD is sufficient, and high resolution is not needed - since any music will mask any noise artefacts, especially at -106dB noise floor, making -130dB a nice figure, but irrelevant ??. Regards, Shadders.
  7. Hi, i do not know - does ASR measure to 1Watt into 8ohms? for all its S/N ? It is not specified for the Benchmark. The review states : "Wow, assuming you play at peak of 120 dBSPL, your noise floor will be at -10 dBSPL! That is absolute silence." If you play at this level, then THD rises, so not sure -10dB SPL is accurate. The 120dB SPL refers to 34dB power (2.5kWatts) for a 86dB sensitivity speaker. This exceeds the Benchmark capability. The RANE site is good for the explanations - the parameters need to be stated for any S/N figure ; https://www.rane.com/note145.html Stereophile specification list for the Benchmark AHB2 does not list the parameters for the 130dB S/N except that it is A weighted. Regards, Shadders.
  8. Hi, Sandyk can confirm this, but the specification for the SC200 was measured for the completed amplifier - not simulation. The ULD was also the measured performance. If you purchase the kits/PCB, and follow the article instructions, then you will achieve the measured performance. Regards, Shadders.
  9. They do all look old, scruffy, and lardy.
  10. Hi sandyk, Yes, there are many excellent DIY designs, which can be built for the fraction of the price. It is a shame that DIY is not more popular. Regards, Shadders.
  11. Hi, If you buy Bob Cordell's new book, there is an example design in chapter 4, with all required ancillary circuits, which has 125watts in 8ohms, and 1kHz THD is 0.0008%, and 20kHz THD is 0.004%, close to the Benchmark. Although the S/N is 100dB A-weighted. Regards, Shadders.
  12. Hi, The specification is A-weighted, so please correct if wrong, removes noise due to the filter. The ASR review probably does not use A-weighting. Regards, Shadders.
  13. Hi, I am not bothered about the ads - i like the ads - seeing other equipment and brands. Regards, Shadders.
  14. Hi, I noticed this about 3 weeks ago - if i have ublock ad blocker turned on, i see the ad at the top and those at the side. If i turn it off, i am prompted to turn it off, and still see the ads at the top and side. I turn it back on, no prompt to turn it off, and still see the ads. So, not sure where the logic problem resides. Regards, Shadders.
  15. Hi, Your subjective listening neither confirms or refutes the objective measurements. You will not know whether you can hear 20kHz+ or not. Again, if you are happy that the manufacturer decides for you regarding your hearing, or that 20kHz+ has no effect in the system reproduction, then ok. The issue is that they present measurements that make their amplifier look better than the usual class A/B amplifier. They restrict the measurements to make their product look better, then claim no other amplifier can be better. I do not think class D should be given such preferential treatment - we should therefore be asking all reviewers to use the 22kHz measurement bandwidth, to level the playing field. Another aspect is the very low output impedance of the unit. I think the performance of the Purifi module is excellent in this regard, but this is at 1amp output current (rms assumed) which equates to 6.83volts peak output into 4ohms. If we have a transient of 20.5volts peak, which is 3amps (rms) into 4ohms, is the output impedance the same ?. At 1amp, the damping factor is 12,000 which is vastly greater than any other amp. The objective measurements are used to present an expectation of performance, and subsequently the listener will hear accordingly. I do not think our hearing is as good as we believe it is. Regards, Shadders.
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