Recently purchased a plastic case ESQ-1. Has 3.5 firmware. After a few days I realized the some of the internal sounds didn’t sound quite right. So I did a soft rest which didn’t change things but doing the filter tuning did help. Many of the patches were soo much better and sounded like the demos on YouTube. I should mention that the filter values displayed on the screen were within the desired range. The problem is they were not “saved”. Every time I power off and on, I have to do the filter tuning. At first I thought the problem was related to the low battery message I received on boot. I replaced the battery today, don’t get the low battery message but I still need to do the filter tuning after a power cycle. Any thoughts? Thanks in advance.
Have you fixed the issue yet ?
I haven’t been able to find the cause of the problem yet. I have noticed that if I modify any program and save it, the programs sound fine. So maybe it isn’t the act of filter calibration but saving the values that fix the sound issue (tremolo sounding like a broken spring). I also notice the problem just doesn’t appear after first power on but after some period of inactivity (when powered).
I have the same problem. Did you try unseating and then reseating the filter chips as seen here: Blog | Ensoniq ESQ-1 Filter Replacement | SynthLib ?
Doing so solved the problem for me for a while, but it came back. I then swapped places of the questionable filter with a good one. The problem went away for a while again, but came back. I’ve now noticed that a filter chip tends to fall below its “good” threshold of 140 or so when I play patches that hog up the polyphony and exceed 8 voices. Other than that, I have no working hypothesis. The filter chips seem fine.