DECWARE.....ZTPRE anyone have any expeiriance with one ?

Gentlemen....I may just bite the bullet and purchase both the Prima Luna and the ZTPRE....cut heads for 2 weeks and return one. I do have access
to Clio and could perform an RTA  to really check that bottom end on both.I am checking into PM's return policy now.

I really do enjoy these types of discussions as I can get so many educated points of view...then again that's why we all love this "hobby" (addiction, habit, relapsing disorder) so much :}
Have a great day,

Kevin

Hi George,

Yes, I’m pretty certain that what I said is correct.

The example you cited, resulting in the cap seeing 50K, applies if the pot is set at max. But since the amplifier with the 100K input impedance is connected to the wiper of the pot consider what would happen if the pot were set, for example, such that 10% of the pot’s resistance is between the wiper and ground, and 90% of the pot’s resistance is between the wiper and the point where the pot and the cap are connected.

With that setting the resistance between the point where the cap and the pot are connected together and ground (i.e., what the cap sees), assuming the same 100K input impedance of the amplifier, would be:

Cap sees: 90K + (10K in parallel with 100K) = 99.1K, not 50K

The rolloff of the resulting high pass filter in that example will be determined by the combination of 0.1 uf and 99.1K. The rolloff (and the corresponding phase shift) will occur at the point where the cap and the pot are connected together, and it will also occur at the wiper of the pot which in turn is wired to the output connector. The signal at the output connector and the signal at the point where the cap and pot are connected together will differ in terms of amplitude, of course, but not in terms of frequency response (putting aside the possible effects of cable capacitance and amplifier input capacitance on high frequencies).

Finally, to be sure we are looking at the same schematic, I am looking at the one shown on the last page of the manual.

Best regards,
-- Al

viking62 said..."Gentlemen,I may just bite the bullet and purchase both the Prima Luna and the ZTPRE."

Sounds like a plan. Please keep us informed...8)

Finally, to be sure we are looking at the same schematic, I am looking at the one shown on the last page of the manual.

Yes I think that’s the one Al pdf you have to rotate it twice, what I see that the cap sees is if the pot is at half way is a series and two parallel resistances, and yes as you say if full up it get’s closer to just 2 x parallel resistances.
Anyway whatever that cap is too small, and should be at least 1uf to take away the problem if close or full up on the VC.

Cheers George