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RE: Roll-your-own Tayloe upgrade

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  • t93x_gordan
    Hi, Are you still happy with this modification ? I am in order OPA1612 if you suggest me! What is your opinion! E72X - Gordan e72x.gordan@gmail.com --- In
    Message 1 of 6 , Sep 16, 2013

       Hi,


      Are you still happy with this modification ? I am in order OPA1612 if you suggest me!


      What is your opinion!


      E72X - Gordan

      e72x.gordan@...




      --- In genesisradio@yahoogroups.com, <k5dbx@...> wrote:

      Well, for me, it was well worth the few dollars and the 20 minutes time. The Audigy2 ZS has an OPA2365 on the input side and combined THD+N on the whole chain is less than the Philips UDA1361T ADC, which in any good design is required, and certainly not present prior to these changes.

      Happy motoring....


      --- In GenesisRadio@yahoogroups.com, "yo9irf" <razvanfatu@...> wrote:
      >
      > Actually, doing the math behind you will see the difference is not that big:
      > - there is noise from all the resistors before the opamps that will add to the total noise figure
      > - when on, the preamp will actually minimize the opamp internal noise impact alot
      > - the lower the opamp gain the smaller the difference too (that noise figure is given for open loop operation)
      >
      > Anyway, all these factors are irellevant if you use a regular soundcard with about 100dB dynamic range and 1V input, because the ADC noise is much higher than the transceiver's.
      >
      > I am using a SDR of my own design and I've tested several opamps, the difference between NE5532 and LT6231 (similar noise with your OPA1612) is about 2dB in noise floor with a good Audigy 24-bit soundcard. It is useles though as with any antenna the general atmospheric noise is much higher than that.
      >
      > What you need to look for in a HF transciever is dynamic range, especially close-in dynamic range.
      >
      > Razvan YO9IRF
      >
      > --- In GenesisRadio@yahoogroups.com, "Bruce kf1z" <kf1z@> wrote:
      > >
      > > ok, from component designation, I assume G11
      > >
      > > Now,
      > > Did you by any chance take any actual measurements?
      > > ( data sheet specs are nice.... but real world even better!)
      > >
      > > Like 'old' and 'new' SNR measurements for example?
      > >
      > > Bruce
      > >
      > >
      > >
      > > From: Bruce kf1z
      > > Sent: Tuesday, July 30, 2013 4:35 PM
      > > To: GenesisRadio@yahoogroups.com
      > > Subject: Re: [GenesisRadio] Roll-your-own Tayloe upgrade
      > >
      > >
      > >
      > > Which radio?
      > >
      > > G11, G59, G3020?
      > >
      > >
      > > bruce
      > > kf1z
      > >
      > >
      > >
      > >
      > >
      > > From: David Box
      > > Sent: Tuesday, July 30, 2013 4:09 PM
      > > To: GenesisRadio@yahoogroups.com
      > > Subject: [GenesisRadio] Roll-your-own Tayloe upgrade
      > >
      > >
      > > Swapped out the 4 NE5532's (U2 thru U5) for TI/BurrBrown OPA1612's today and well pleased with the sensitivity.
      > >
      > > Old
      > > Input Noise 5 nV/ãHz
      > > Slew 9 V/ƒÊs
      > > CMRR 100dB
      > >
      > > New
      > > Input Noise 1.1nV/ãHz
      > > THD 0.000015% at 1kHz
      > > Slew 27 V/ƒÊs
      > > CMRR 120dB
      > > IMD Twin-Tone -143dB (0.000008%)
      > >
      > > Happy rolling-your-own Tayloe...
      > >
      >
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