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Old 3rd November 2011, 10:25 AM   #21
AWaudio is offline AWaudio  China
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Oh the power supply is taken out for a standalone photo, after intalled into the enclouse it's there near the transformer in photos in first attached PDF. The AC input is with a fuse at 2A. Thanks for your interest, also I've made a kevin gilmore pure class A headphone amplifier dynahi with an enclousure looks similar, sharing the same power supply, two seperated +/- 30V channels for L and R.

3) Which section shows the first picture of the second attached PDF ??

Thank you for your advices.[/QUOTE]
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Old 3rd November 2011, 10:32 AM   #22
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Quote:
Originally Posted by AWaudio View Post
Appreciate very much for your post about Tone Control information, I'd read it carefully later. I once tried the classic passive and active tone control filter in this E-100 DAC and at last I decide not to include it at this moment, but I do want to include some good performance circuit to enable the EQ. For you question.
1) It's 38$ for 3KG and 45$ for 4KG by Fedex, arriving at around 4 ~6 biz days. I've no idea how much it exactly weighs, may tell you later.
2) No idea have not compared it with PCM1704, maybe you can do it and share the result
3) It's the power supply of the whole machine, two seperated channels of LM317/337, with fully protection diode and sufficient WIMA Rubicon capacitor for filter, 4700uF/63V*2 for main filter. It sounds dead quiet, leave the input or press the pause of your CD player, turn the volume to max you hear nothing as if it's not powered on.
Thank you for your reply so as your shipping cost information and explanations.
Concerning the power supply I would avoid serial voltage regulation with LM317/337 (although most engineers prever this methody), because particularly the LM337 tends to oscillate and provides varius other unwanted effects (unfortunately not often, but sometimes - and strongly dependend of the individual manufacturer and the charges).
I recommend a shunt regulted version, as you can see by the RIAA head amp PP2 from NAD - go to post #5 about
Head Pre for Denon DL 103
now there is the additional advantage of the use of arbitrary values of capacity in parallel to the actually loads (output stage and so on).
This isn't possible by the use of serial voltage regulators behind the regulators.
The not "build in" tone control in your DAC is a good idea, because severeal users uses also analog stuff like record player with RIAA stages, cassette recorders and other such stuff. Thus the tone control must be inside in the actually preamp section, where is also integrated the source select switches and the volume control parts.

Last edited by tiefbassuebertr; 3rd November 2011 at 10:41 AM.
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Old 3rd November 2011, 12:10 PM   #23
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Right I agree, not to serial LM317/337. So in the E-100 DAC the two group of 317/337 are seperated, one group for the low noise signal and another for the power amplifier, the head amp circuit. This seperation is expected to enhance the performance.

I still have no idea if should embed the ton control in the circuit, I'd love to so long as if it's not going to bring in extra system degration.

For some guys without a preamp or dedicated tone controller, allowing them to adjust the EQ might bring a lot of fun. However the preaquisition is no extra performance degration by built the EQ in. or Maybe EQ by DSP processor? That's creazy.
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Old 8th November 2011, 09:19 AM   #24
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I'm now seriously thinking about adding a DSP processor in the system for Digital filter as I think this is much better and will help to filter the over sampling noise, although the high frequency noise can not be heard, but may inter modulation with signals of other frequency. And if you look into the circuit of other top CD players there are usually a DSP inside it as the digital filter. One big plus is you can do EQ with a DSP processor.
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Old 8th November 2011, 09:51 AM   #25
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What is over sampling noise? CD players do use digital filters that's true, but in general they're not DSPs, rather they are dedicated FIR hardware. Including a DSP would allow much more flexibility and be more attractive to customers as then they could select whatever filtering option they like. Few people would actually want EQ though in their CD player, that's a pre-amp function.
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Old 8th November 2011, 04:26 PM   #26
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Check what's in Marants CD7 player

Quote:
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What is over sampling noise? CD players do use digital filters that's true, but in general they're not DSPs, rather they are dedicated FIR hardware. Including a DSP would allow much more flexibility and be more attractive to customers as then they could select whatever filtering option they like. Few people would actually want EQ though in their CD player, that's a pre-amp function.
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Old 8th November 2011, 04:31 PM   #27
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Talking about EQ, every component can contribute to EQ, the tone of the circuit, and frequency components. With a DSP you are able to adjust it as you like, often a slight change/compensation would be enough to bring out your own flavour of music. So EQ in source is not for scaling frequency balance but for flavor.
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Old 8th November 2011, 05:33 PM   #28
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And the art of sound/audio circuit should not restricted to the analog field. Digital technologies brings in revolutionary.
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