John Curl's Blowtorch preamplifier part II

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The spec sheet is often out of date or a quick look doesnt reveal it true potential for audio...... when I used the LT1468 in an oscillator circuit of moderate circuit Z values I easily got -120dB THD over the audio range of freqs. Not for phono carts but works well for many other apps. Some data sheets are conservative and others are minimum and others are max and other specs are typical numbers. Some times you just have to measure it in your circuit and see what you have.


THx-RNMarsh
 
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diyAudio Member RIP
Joined 2005
No, it's one channel shown, and Cart + and Cart - are the cartridge coil connections, which float. L is cartridge coil inductance in uH, R is cartridge coil resistance in ohms. It's a floating MM/MI phono preamp with partial transimpedance loading, essentially forming the 75uS RIAA pole as a freeby.
Yes billshurv is right, I meant inductance and resistance. I figured it was some fancy synthetic loading. If you can believe this, I was working on a somewhat similar approach yesterday, although with no attempt to make things balanced.

Bernie was a smart dude, although by all accounts he did not suffer fools gladly. I wish I had known him.
 
diyAudio Member RIP
Joined 2005
Who is Bernie?
Yeah I guess Barney was the more common appellation.

He published a lot. I have a collection of his writings that was a sort-of-tribute but by no means includes everything.

He's almost gotten his name attached to biasing schemes for class AB output stages --- had he a fancy name like Hawksford or Baxandall he might have more success in that regard. He and Cage edited a popular electronic measurements book. I like his paper Thermal and Quantum Noise a lot, although it is becoming a tad dated according to some.
 
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