variable crossfeed?
Nov 8, 2008 at 2:12 AM Thread Starter Post #1 of 5

linuxworks

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I'm looking at cmoy's article:

HeadWize - Project: An Acoustic Simulator for Headphone Amplifiers by Chu Moy

and I see that r1a and r1b are just 2 alternate R's to select the 'level' of crossfade.

so why not have a variable R there, perhaps even limited at both ends (ie, not '0..n').

have people done that? is it a waste of time? any other reason NOT to have a dual pot+R there?

I've seen some ebay amps that have 'variable crossfade'. are they doing this or something else?
 
Nov 8, 2008 at 8:33 AM Post #2 of 5

tangent

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There was a discussion on Headwize not long ago about using one of the ALPS RK097s for this. Most of the thread focused on how to get its 10K resistance down to something suitable for the modified Linkwitz circuit, but there was other discussion that you might find interesting.
 
Nov 8, 2008 at 3:40 PM Post #4 of 5

linuxworks

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I still didn't find too much here on this forum but I did on headwize. cmoy himself says:

Re: the value of R1, I would keep it less than the total of R4 + R5.

so given that r1 seems to be 1.5k at min and cmoy wants the max to be 2*3.3k, it sounds like my first trial should have a 1k R in series with a 5K pot (more or less).

maybe I'll try that later today. I assume that if I panel mount this pot that I'd also want to keep the wiring as short and direct as possible and I'll see what I can do about that. the wiring looks like it might be easiest to just mount that pot+R directly at the rear panel where the in and out RCA jacks would usually be, that way the pot can 'string between' the in and out pins for each channel.
 
May 11, 2010 at 11:05 PM Post #5 of 5

Fred_fred2004

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This is interesting I was trying to do a layout last night, I agee with the resistor in series but I used a 1K5 so that would set the min. and I wanted to get the pot out front of the enclosure
 

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