I have just been given a 4040 S2 amplifier. Unfortunately, the left output channel is somewhat distorted. At quiet volumes it sounds fine, then as the volume is turned up, the distortion kicks in.
As the volume is further increased, it is only the distortion that increases - the overall volume of the sound eminating is still relatively quiet. I would describe the distortion itself as sounding a little like white noise, or digital saturation.
Anything that stands out as a possible culprit here? I don't have a schematic
- I have emailed Creek but who knows if they'll reply.
For this type of fault the output stage and related driver circuits will have to be troubleshooted. It is very possible that one or more of the output or driver transistors are defective, or any of the support components. It is impossible to take a guess at this. An experienced tech who is used to troubleshooting these amplifiers can service this for you.
What is your level of skill with regards to servicing electronic equipment? Do you know how to identify the various components found within the amplifier? Do you have the proper tools to do the work? Do you have a basic understanding of the way in which a DC-coupled solid state amplifier works?
If you don't have a basic understanding of how this stuff works, your likelihood of success in repairing it without assistance is very low.
Also, your chance of causing more damage is fairly high.
If the amp has pre-out/main-in jumpers on the back remove them. Replace them with a patch cord so that the left pre-amp out goes to the right main in channel. Does the distortion move to the other channel? If it does, the problem is in the pre-amp (unlikely but possible). If it does not, the problem is in the amp.
If the problem is in the amp, I'd pull the output transistors and test them. Given that the amp (and thus the transistors under test) seems to work fine at low volume, this might be easier said than done without some specific test equipment. If the outputs test OK, get a schematic. Inject a sine wave into the amp's input, and use your oscilloscope to trace the signal path. You'll get to a particular component or group of components or integrated circuit where the signal looks good going in, and distorted coming out. You've found your problem area. Depending on what type of component, what its' function is, where it's located, you may need to test various other components in order to determine what's actually broken. Also, realize that if the outputs are failed, there's a possibility that another fault elsewhere in the amp took them down, and that new ones may blow immediately upon installation.
FWIW, it's an expensive amp that you got for free. I'd pay somebody to fix it rather than take the chance I'd butcher it as my first foray into electronics repair.
Good luck.
Dave
I'd say there's a good chance that it's either an output transistor or a driver/pre-driver on the main amp board, but I'm often wrong.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.