[pretzel_logic]

I am trying a passive preamp with 2 sets of inputs 1 for phono and 1 for CD.  I'm wondering if I should use the .47 or 1uf caps, I have the 1uf in now.  I have tried the passive with the cornet and had to use resistors between the inputs and the pot, it's a 10k pot.  I first tried a 10k resistor but lost a lot of hf, went with a 1.5k on one set of inputs and 5k on the other and compared between the two, 5k seemed to work best.  

What is the best way of determining which resistors to use if the passive will even work for me.  Right now it's an experiment, I have a cheapo $2.50 pot in it now.  Am trying to figure out how to determine input and output impedances, but not much luck so far, not sure what my amps input impedance is, Modded Dynaco MK III's using Uncle Neds SDS and output boards.

BTW, the Cornet is working great now.  fingers crossed I don't blow another tranny, though am hoping it was the bad rec tube.

Brian

[hagtech]

Don't put any resistors in front of the attenuator.  If it is 10k, then leave it at 10k.  You will also need to up the coupling cap in the Cornet to 1uF.

Step 2, put the attenuator right at the input of the power amp.  That is, VERY short output cables.  Put the distance between the Cornet and the preamp.

Adding the constant current sink to the Cornet output stage will help.  Or go with the octal version.  Roll the 12AU7 until you find a dynamic bitchin' one.  Some will sound really flat.  That's where you put the money.

jh

[pretzel_logic]

Thanks for the advice Jim.  The passive is just an experiment at this point.  So far I have much better dynamics than with the PAS 3 I was using, but w/o the resistors I found the upper highs to be a bit shrill, more so than before.  I think what I'm most happy about is the dynamics though, I'm finally getting all the upper bass notes that I was missing before.  I already have the 1uf Multicaps in place of the .47 and my cables are about 3 feet long between the amps and the passive.  Maybe the CCS should be my next step and also a decent attenuator in the passive.

I'm also looking forward to your new linestage.  That will be my next project I'm sure as I'm very happy with the Cornet, still only has about 25 hours on it and sounds great.

Brian

[pretzel_logic]

After looking over my wiring and fixing the wiring I had backwards, I now have just about perfect gain from the Cornet through the passive pre to the amps.  I definitely have very good dynamics, excellent bass impact and better overall detail.  My highs are a little bright but I will try tube rolling to try and correct that.

Brian