Amplifier volume crackle

A number if things can be wrong with it, from the audil preamp to the the audio amplifier. Even as simple as a bad volume control. Does the actual noise change patterns when you move the volume?

I'm not sure which amp you're playing thru. but generally the settings you want for a clean sound. check your drive (or Gain ) knob. You want it about half way.and your Channel volume, half way. those are good starts. then let your master volume do the rest. Also, make sure, if you have active pick-ups on your guitar. check the batteries. if they're low, it can cause distortion. if this doesn't resolve, then its internal. could be anything at that point.

Please add more information to improve help, does the amp just distorts in that particular note or teh entire sound is distorted? does the amp distorts at low volumes?

try using less compression

It looks like the Korg c-15s has a internally mounted speaker and so I will assume that the speaker and amplifier are part of the piano base. It sounds like either the speaker is blown (crackling sounds heard as deformed voice coil scrapes the magnet structure) or the audio amplifier is distorting the audio.

Connect the piano's output to an external amplifier and speaker to properly identify problem.

Check for degradation of C144 a 2200mfd/16volt cap.

This is power source for the 5 volt digital hardware. Check for excess ripple with a scope. The voltage should NOT go below 8 volts. If the voltage dips, the DSP will go nut-case.

Using a common lead pencil, gently tap on the smaller tubes in the unit, listening for noises and crackling to change and the drive channel changes.

It is normal to get a slight twang when doing this from the microphonics of the tubes, however, the crackling and up and down volume points to a bad tube.

I have a Korg C-15s and also experiencing loud crackling sounds when I turn it on. The problems seems to be either the sliding volume control or the amplifier itself. Honestly though, I believe the issue is the volume control. I opened my piano to get a closer look and attempted to clean the contacts on the volume. Unfortunately after cleaning the contacts, the crackling sounds became somewhat worse. After I turn the piano on, the volume control is generally rendered useless......volume set to low volume and the noise is quite loud and other times the volume control is set high and get very low volume crackling noise. No real consistency. The noise does diminish after a few minutes but so does the piano sounds to an inaudible level. There were a couple of instances where I turned it on and surprising enough, no no noise and perfect sound. For these reasons I believe the issue is within the volume control and not so much the amplifier. I have an electronics background and noticed that the volume control is very unique in design and is not something that can be substituted with another volume control from other sources.

My recommendation is to check the sound quality of the audio from the RCA L/R audio outs on rear of the piano by connecting to a stereo receiver. If it sounds fine you're in luck. If the crackling sound does not diminish after a few minutes like mine does, I would suggest disconnecting the internal speakers and using the audio out only. You can connect a pair of studio monitors or high quality computer speakers, preferably with a small subwoofer to deliver the full audio range and deeper tone of a real piano. I'm currently using a basic pair of Logitech computer speakers and is quite acceptable until I can afford a high quality set of monitors or relocate my piano closer to my high quality Yamaha receiver.

I hope this info helps a bit.

With everything switched off. I will surmise that you are using the onboard battery with the foot pedal and not a power supply.
1. Plug lead from guitar/instrument into INPUT side of pedal
2. Plug lead from OUTPUT side of pedal into amplifier INPUT.
3. Turn amplifier volume to about 10 o'clock - to stop blowing your ears out.
4. Turn volume up on guitar to acceptable level.
5. press foot switch on pedal and adjust pedal controls to suit your type of distortion.
6. Play like Hendrix.
Good Luck
ps Just as an after thought rechargeable 9volt batteries are the way to go. I've been using them for years as I always get caught up in the power cable.
If you're going to add another pedal like a Phaser, Compressor, Flanger or what just use small connect leads between each pedal but always, always put the compressor pedal last in the line.

Insain is distorted but cleen is not