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stereo coffee

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  1. stereo coffee

    My System this morning

    Can we have a return please of the toe in images.
  2. stereo coffee

    Cambridge Azur 650T AM/FM/DAB+ Tuner

    A few tips - always have the power cord disconnected if covers are removed. Check that the voltage selector - if fitted is still set at your mains voltage. Contact Cambridge for assistance - https://www.cambridgeaudio.com/en/contact
  3. stereo coffee

    Amplifer to drive Revel Performa F30s

    A Quad 909 would both fit the budget and be excellent, partnered with a passive pre.
  4. stereo coffee

    Preamp benefits

    A passive is an excellent choice, you will need a power amplifier with reasonable sensitivity - ideally specified as requiring 1.5v or lower for full output. There are many forms passives can take, from traditional volume controls with the number of inputs you need, to opto coupled passives. You may even want to look at DIY designs.
  5. Yes companding is well known to benefit audio recording and playback, DBX made many models found here: http://vintagedbx.free.fr/index.html DBX founded by David Blackmer were always ahead of Dolby, both companies using emphasis and de-emphasis suggested by Murray Crosby https://en.wikipedia.org/wiki/Crosby_system Ironically both DBX and Dolby were later used as noise reduction systems in FM broadcasting, the irony being where emphasis and demphasis originated as technique to improve signal to noise ratio. https://en.wikipedia.org/wiki/FM_broadcasting
  6. A 75 ohm cable is 75 ohm because of the dimension and the consistency of that dimension between its inner conductor and its shield. It falls into a class of connection called a transmission line. 75 ohm exists to try to preserve the frequencies involved with SPDIF https://en.wikipedia.org/wiki/Transmission_line We can see using a RCA termination straight away disobeys 75 ohm connection, SPDIF should be connected with 75 ohm coax and RF connectors and the BNC is is the obvious candidate. and worse not using a 75 ohm cable guarantee's reflections across the interface of transport to DAC To measure compliance or non compliance to 75 ohm requires insertion of a VSWR meter https://en.wikipedia.org/wiki/S/PDIF "Many S/PDIF implementations cannot fully decouple the final signal from influence of the source or the interconnect. Specifically the process of clock recovery used to synchronize reception may produce jitter " I suggested a way around this in June of 1997 http://enjoythemusic.com/magazine/viewpoint/0401/deficienciesofspdif.htm
  7. stereo coffee

    The job of a pre amp

    But if you remove the impedance matching issue first, by using source components with sufficient ability to drive a load, you are just left with the need to attenuate. Similarly if you have a power amp needing effectively a power amp disguised cleverly as a preamp to drive it, well that's a problem, but can be solved by reviewing the sensitivity for full output figure, lower being better for passives. Its a choice to be made, trying each and knowing which is better, is the thing to do.
  8. stereo coffee

    The job of a pre amp

    Correct, now start looking at those implementations, to see if one might be better than the other. You may find along the way certain technologies are capable of reducing distortions giving you beneficial answers vs others that add distortion.
  9. stereo coffee

    The job of a pre amp

    That's great , that it responds as it should.
  10. stereo coffee

    The job of a pre amp

    Wire if used with the benefit coax brings can largely be ignored at audio frequencies, where coax is not used wire should be considered as an antenna. You are right I was referring to the least number of components vs adding more components to a signal path, does the audio you are hearing improve or does it get worse with more components ?
  11. stereo coffee

    The job of a pre amp

    It was a bit broad I agree, but did it help?
  12. stereo coffee

    The job of a pre amp

    Lets go back to 1986 just say your at a Dire Straits concert, and you have been a fan all your life and due to expenditure on the car last week and the kids wanting more toys, you could just not afford front row tickets when they were on sale 2 months ago. Instead tonight your parked outside the grounds, well its loud enough and you have seen Mark play before on TV so you enjoy what you can, you are accepting certain distortions including sound bouncing off numerous objects and generally nicely distorting the audio event. Lets now go to where you are closer, the front row will do .... is that better or worse.
  13. stereo coffee

    The job of a pre amp

    Measurements of flat frequency response to upper limit of ?, but what happens after that ? If our audio systems were time invariant, or even partially time invariant, we would start to see harmonic distortions begin to cancel. Now factor in an active pre vs a passive in terms of its ability to represent timing of the electrical signal originating at the source. In this context is a short path worse or better ?
  14. stereo coffee

    The job of a pre amp

    Until you have heard it without those distortions.
  15. stereo coffee

    The job of a pre amp

    Thanks davewantsmore, but on this occasion referring to the invention of the rheostat what we use in abundance today as method of altering volume , patented in 1920 by Mary Elizabeth Hallock Greenewalt to indicate (ironically ) light gradations for her musical instrument- Nourathar https://en.wikipedia.org/wiki/Mary_Hallock-Greenewalt http://www2.hsp.org/collections/manuscripts/g/0867Musical.html
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