Thanks for the great forum! This is my third post, and really a prime reason for my joining. I am looking for some help with understanding what might possibly be wrong and how if maybe there is a fix.
My Alesis QSR piano sounds (all of them piano based programs) have wierd behavior where distortion kicks in. It is constant and sporadic. I could attach or link to a example if you like to hear it.
It only happens in the piano sounds. I play a few notes and one starts to wildly randomly distort. I play a full chord, and the whole thing is distorted. I play a few notes in a melodic line and one note starts to distort, on any random key, but primarily or more often in higher registers, but really without any consistency.
Have you ever heard of such a thing, and do you know what might be causing it and how to maybe fix it?
Please let me know if you need any further info or would like a sound bite (byte) example.
Have you tried reinitializing the QSR? That may solve the trouble easily (or it may not…) Here is the process:
If your unit behaves erratically or “freezes”, the first step is to power down the unit
and power it back up again. Disconnect any cables connected to the MIDI IN jack,
and make sure that a sequencer or keyboard is not sending messages to the QSR that
would make it behave erratically (such as a long stream of pitch bend messages on 16
channels simultaneously). If these steps do not solve the problem, you must re-
initialize the software
To re-initialize the QSR, hold down both CURSOR buttons while turning
on the power. This will reset all Global parameters to their default settings, and will
initialize all edit buffers so that all Mix, Program and Effects parameters are reset to
their default settings. However, none of the Programs, Mixes, or Effects are changed
when re-initializing the unit.
I would suspect the op-amp 5532 or capacitors in the audio circuit or power circuit are going bad.
For capacitors look for evidence of “leaking” or anything around them on the circuit board or cracks and swelling of capacitors. unsolder and replace any one suspect…there aren’t that many .
For the op-amps 5532 inject a clean sine wave at the output jack and follow the audio backwards thru the op amps and transistors back to the output of the DAC.
Capacitor failing typically due to heat or age breakdown inject a crunchy distrotion. I suspect you notice it mostly on clean recognizable sounds like an analogue piano sound you are very familiar with, some synths sounds you may actually hear the crunchy addition but like the way it sounds in context.
Capacitors and op amps are inexpensive and easy to replace, well worth just replacing to elimate them as a possibility and future issue clean-up. Once you trace back to the analog output of the DAC there is no reason to go futher back as the digital signal is immune to crunchy noise…hope that helps.
Thank you Ron! I always wanted to learn how to solder and repair this and other old synths.
Most of what you said is over my head at this time. But I am watching lots of Synth Wizard videos and other more tutorial type synth repair videos so am really inspired to give it a go.