[robonbass]

hi - I am considering a hypex ncore project run from a passive pre. I wonder if anyone can suggest appropriate pot values - I know this is a can of worms! the source will be a CD player 2v output, output impedance 10K. I can't even find the input impedance for ncore, doesn't seem to be published?? whether I run a 6tf low cap cable to outboard power amps or install pots in power amp are open options and I am sure will illicit different advice ... I would probably get a selection of values cheaply, listen to each, and then buy a decent pot. where to start???

[FullRangeMan]

The usual rule of thumb impedance for pre x amp is 10x more or 100K ohm in your case.

[navi]

hi - I am considering a hypex ncore project run from a passive pre. I wonder if anyone can suggest appropriate pot values - I know this is a can of worms! the source will be a CD player 2v output, output impedance 10K. I can't even find the input impedance for ncore, doesn't seem to be published?? whether I run a 6tf low cap cable to outboard power amps or install pots in power amp are open options and I am sure will illicit different advice ... I would probably get a selection of values cheaply, listen to each, and then buy a decent pot. where to start???

10K for a CD player seems a bit high. what CD player is it?

[poseidonsvoice]

Here is the datasheet where the differential input impedance (105k ohms) is revealed: https://www.diyclassd.com/img/upload/doc/ncore/nc400/Documentation/NC400_04xx.pdf

Plenty of other data and equations are included as well. Best to look over it a few times and save it somewhere.

Best,
Anand.

[Phil A]

Welcome to the forum

[matevana]

For what it's worth I have a similar setup:  CD Player -> Passive Pre -> Wyred 4 Sound ST Power Amp

The W4S amp uses an ICE power module (not Hypex) and my Passive Pre is made by Luminous Audio and contains a 50k audio taper Alps blue pot. It is well matched from the stand point that typical listening occurs near the 12:00 volume knob position.  The passive pre is both transparent and non grainy; I actually prefer it to some of the ladder type stepped attenuators I have tried from Goldpoint, etc. which some believe are superior.