How important is signal to noise ratio when choosing a preamp?

Discussion in 'Archived Threads 2001-2004' started by Keir H, Apr 9, 2002.

  1. Keir H

    Keir H Second Unit

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    So would preamp A: having an 87db snr sound not quite as good as preamp B: with its' 105db snr? WHere do you measure this. Are detail and dynamics lost? Example: the new Outlaw 950 I think has a snr of 120(?)db while say a HK Signature 2.0 has merely 87db. COnfused...thanks for clarifying.
     
  2. John Kotches

    John Kotches Cinematographer

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    Keir,

    SNR affects the noise floor of your system.

    Practical example... Have you ever gone up to some speakers, and heard a hissing sound? That's the noise floor of the system. No sound softer than that hissing can be reproduced -- it will be obscured.

    At the moment, I'm lucky enough to be using a preamp at >110dB SNR published (off the record I'm told 118dB) and an amplifier at a little more than that. My system is dead quiet with no source playing back.

    That's the practical aspect of the difference between the two SNRs.

    Regards,
     
  3. Larry B

    Larry B Screenwriter

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    John:

    What equipment are you using?

    Larry
     
  4. Saurav

    Saurav Cinematographer

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    There was a loooooooooooong thread a while back on SNR and its relevance to sound quality, specially with regard to preamps. If you ran a search for it, you might find some interesting information there.
     
  5. John Kotches

    John Kotches Cinematographer

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    Larry,

    I have a Meitner Switchman Quartet mulit-channel analog preampifier, and a Cinepro 3K6, Series 3 power amp.

    The processor (and multi-channel sources) are fed to the Meitner, which feeds the Cinepro.

    Regards,
     
  6. Kevin. W

    Kevin. W Screenwriter

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  7. Jeff Hipps

    Jeff Hipps Stunt Coordinator

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    Were I to see two prepros, one with S/N spec'ed at 87 dB and the second at 105, my first thought would be that the two were not spec'ed the same way.

    I further suspect that many of the numbers we're seeing reported here are referenced to full output in the analog domain and may not reflect real-world digital S/N's.

    From reserach published by Bob Stuart of Meridian, we need about 18 bit performance to guarantee that the noise floor will not intrude on the performance. This is the equivalent of 108 dB S/N. With today's technology, this is available for line level components and for power amps. It is not, in my opinion, available for phono stages or for Dolby Digital/DTS decoding.

    Jeff
     
  8. Larry B

    Larry B Screenwriter

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    This is directed to all you EE-types:

    I have heard a variety of stereo preamps, rangin in price from 1,000 or so up to about $15,000. The quality of the sound from these units (which, by the way, generally tracked price) spanned a pretty big range. So here's my question: Does the SNR in any way correlate, or better yet, explain, the sonic performance of these units?
     

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