Lexicon LXP-5 Pot Deterioration - 100% EASY FIX

[coachla]

I've been using a pair of LXP-5's for the past 35 years to elevate my vertical mix. The pitch delay algorithm has an ambient Reverb that can be detuned to help with this. I bought this particular LXP-5 along with another 20 years ago. This one had seen a lot of use and had deterioration of the pots and some drifting of the encoders, but it was still very functional until just recently. The other of this pair never had such a problem and still today has no deterioration of the pots (only the encoders). So it can't be said that they all do it, but I think most of them pretty much go south at some point. I just wanted to post a quick solution for anybody who owns one of these units which has been impossible to use because of the awful crashing noise that they tend to make.

I set my inputs at 12 o'clock, Mix wide open wet, and the outputs at 2 o'clock. I didn't have the resistors at hand to replicate this, but no matter, it just means re-adjusting my sends and returns a bit.

See the photo of the board and notice I am using only the left channel (in both). The LXP-5 mixes the stereo inputs which is of no use to me since the objective is to separate high frequencies as much as possible. The ambient reverb by default is sent to the left output channel in the LXP-5.

Since I use only Sounddiver to edit all my equipment, I had removed the encoders quite some time ago because of their annoying erratic drifting. Now I removed the Input, Mix and Output pots.

Note that input (from physical jack) is on the left, ground is on the right and wiper (to amp input) is in the center. I only had a handful of resistors, so based on what I had measured my knob settings to be I needed to have the proportions be 7:1, so input to wiper is 7 times wiper to ground. Substituting the Mix pot I simply made a jumper from a resistor lead bridging the physical input to the amp input, ignoring the ground, and likewise for the Output pot. So resistors need only be used to replace the Input pot. Just bridging does not work in the case of the Input pot.

I removed the pots from the other of the pair, so they are equally balanced. They sound very good. I hope someone will find this helpful.

[mrhappy]

Thanks for that coachla! I’ve never used those units but have always been intrigued! Seems like a visit to eBay might be in order!