madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: lincolnic on February 02, 2014, 05:47:16 AM

Title: Zero Point SDX: More usable feedback knob? (And mode question)
Post by: lincolnic on February 02, 2014, 05:47:16 AM
As threatened in the "weekend plans" thread, I did finish up my ZPSDX today. I'm pretty happy with it, but the feedback knob seems to only be usable up to 9:30 or 10 o'clock. After that, it's into self-oscillation. Anything I can do to spread out the usable range?

Also, which of the delay modes are which? In the build doc, they're listed (from top to bottom) as Analog, Tape, Shimmer, and Deep, but the descriptions don't match up (to my ear) from how the rotary switch actually turns. I'd expect the Tape setting to be the grittiest/most saturated, but I get that sound when the rotary is in the third position from the top - what the build doc lists as Shimmer mode. What's the correct order?
Title: Re: Zero Point SDX: More usable feedback knob? (And mode question)
Post by: midwayfair on February 02, 2014, 02:15:14 PM
Quote from: lincolnic on February 02, 2014, 05:47:16 AM
As threatened in the "weekend plans" thread, I did finish up my ZPSDX today. I'm pretty happy with it, but the feedback knob seems to only be usable up to 9:30 or 10 o'clock. After that, it's into self-oscillation. Anything I can do to spread out the usable range?

Use an audio taper, or strap a small resistor across lugs 1 and 2 to change the taper.
Title: Re: Zero Point SDX: More usable feedback knob? (And mode question)
Post by: lincolnic on February 02, 2014, 05:56:06 PM
Thanks, I'll try the resistor method first - if only because it's quicker than changing out the pot altogether. I've done some reading (Secret Life of Pots, AMZ's "Modifying Pot Response") and it looks like I'd want to try a 10k resistor. Does this seem reasonable, or should I go smaller?

Also, if anyone knows the answer to my mode question, that'd be helpful. I'm holding off on labeling the enclosure until I get that sorted.
Title: Re: Zero Point SDX: More usable feedback knob? (And mode question)
Post by: Blues Healer on February 04, 2014, 08:17:17 PM
I kinda doubt this will answer your mode question, but I noticed on a recent build report -- it may have even been for a Multiplex, but the principle is the same -- they had the labeling on the right, and had to reverse the labels. Hard for me to explain without a graphic, but I think you can see why.
Title: Re: Zero Point SDX: More usable feedback knob? (And mode question)
Post by: lincolnic on February 05, 2014, 05:38:35 AM
Thanks, I do understand what you're saying, but unfortunately it doesn't answer my question! Makes sense though.