-=> Roy J. Tellason said to Greg Mayman
 -=> about "BAG OF CHIPS" on 02-05-04  04:06.....

 RJT> Sounds reasonable to me.  What really bugs me is that I *know* I've
 RJT> seen schematics for this sort of thing,  bunches of times over the
 RJT> years,  and can't remember where the heck they've gotten to.  I've done
 RJT> a little bit of digging,  but having a 4-drawer file cabinet of stuff
 RJT> all mixed together I didn't get too terribly far into it.  One of these
 RJT> days I'll probably get back to that,  when I can get to that file
 RJT> cabinet again. 

I've NEVER seen a schematic for this kind of thing, only for RIAA
equalization for magnetic pickups. I had to work this one out
from scratch.

Now, I make no claims that it will make any measureable
improvement in the sound.

OTOH it's a simple network, so it won't hurt to try it.

But I made a colossal booboo in my circuit, by swapping the
positions of the two resistors. Please revise by putting R1 where
R2 is, and R1 where R1 is.

Briefly, the the larger resistor is the one across C1 and the
smaller one is the shunt resistor to ground.

The response is flat below 500 Hz, then rising to about 2KHz and
flat again above that frequency.

The lift above 2KHz is about 6dB relative to the LF end, so I
guess it would be noticeable. Better? Well, given the normal
performance of ceramic pickups, it may not be.

 RJT> Worse yet,  I kicked this around quite extensively a while back,  and
 RJT> lost a bunch of the archived echomail when a drive failed,  so I lost
 RJT> all that discussion.  Oh well.

I remember the discussion, but I didn't save it.
 
 GM> The only other factor is the possible noise in the amplifiers. 

 RJT> Yes.  But the output of a ceramic cartridge is pretty hefty,  so I
 RJT> suspect that won't be much of a problem either,  particularly if I end
 RJT> up using a unity-gain buffer and some equalization as a
"preamp".  The
 RJT> load is going to be the line input of my sound card...

No, noise shouldn't be a problem. I just mentioned it in case ;-)

   ,-./\
  /     \ From Greg Mayman, in beautiful Adelaide, South Australia
  \_,-*_/    "Queen City of The South"    34:55 S  138:36 E
       v

... Men willingly believe what they wish. - Gaius Julius Caesar
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