Phono pre with Jfet and then ad815 at the second stage.. - diyAudio
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Old 23rd January 2015, 03:47 AM   #1
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Default Phono pre with Jfet and then ad815 at the second stage..

Im thinking to use this simple phono pre amplifier

http://diyaudioprojects.com/Solid/JF...-Schematic.png

The above circuit gives about 0.35mV and would that be sufficient to drive the AD815?

after this would like to use the AD815. Will that be ok?
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Old 23rd January 2015, 04:32 AM   #2
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There should be no trouble adding an op amp at the output. But why the AD815? it has fairly high distortion for an op amp and it's designed for driving a low impedance.

There is the LME49720:

LME49720 | Audio Operational Amplifier | Audio | Description & parametrics

it's very low noise!

and there are others.
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Old 23rd January 2015, 04:33 AM   #3
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So the AD815 does the RIAA? You know you can't put caps across the feedback network for CFB amps? 350uV RMS I think might be a bit of a low signal even for the relatively low noise AD815.
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Old 23rd January 2015, 06:53 AM   #4
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Quote:
Originally Posted by abraxalito View Post
So the AD815 does the RIAA? You know you can't put caps across the feedback network for CFB amps? 350uV RMS I think might be a bit of a low signal even for the relatively low noise AD815.
agreed so no chance of using AD815?
actually myrequirement is one phono preamp and one preamp for the DAC output so for phono i thought to use the input stage as the above circuit and the output with AD815 so i think its ruled out there so how about using OPA627 in that place?
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Old 24th January 2015, 12:59 AM   #5
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Quote:
Originally Posted by rhythmsandy View Post
agreed so no chance of using AD815?
Have a look at this appnote - http://www.ti.com/lit/an/slyt099/slyt099.pdf
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