I am using a sherwood integrated amp. I have had this amp for a few years now never had a problem. I moved house last year, and it was packed away for about a year. I recently used it to play music at a friends house and connected it to the laptop no problem. so i decided to connect it back up when i got it home. When i plugged the laptop in the sound was very distorted and the bass wasnt coming through and other times the bass is loud but the treble messes about. The sound is very quiet as well. I checked the speakers and they are fine, and the laptop is working fine. When i plugged the headphones directly into the amp and the problem was started again, i checked the fuses and all and they seem ok. Now when i turn it on, it sounds as if the amp is not earthed. Sorry if this is long winded. Can anybody help.
What input are you using? Please tell me it's not the Phono input (if your Sherwood has one). If so, it could be that the Phono input has a turntable gain stage which could do pretty much what you've described.
I am connecting the laptop up through the auxillary phonos sockets using a phono to check jack cable. As i have allways done in the past. I am not sure what the turntable gain stage is.
Disconnect everything other than the speakers. With no signal coming into the amp, there should be no noise. If there is silence, then you probably need a new cable for the connection to your laptop.
If there is the same noise in the no signal situation, you need to have the unit serviced. There are numerous causes for the noise you describe, the most common being a defective capacitor. Ask for an estimate of the repair costs and then decide whether the unit is worth saving.
When a similiar problem happened with me where the sound was distorted quiet and unbassy it was because of a fuse that had gone. This was a standard glass fuse in a NAD 3130 which was easy enough to replace with a quick order of the right part number from a website. The hum though could be something different (or more than one fuse gone?)