How to get rid of hum from Linn LK140

30% of the time, a hum from the transformer in the amp is a problem with the amp. The other 70% its a problem with your mains supply to the amp.

I would advise that if you have a Linn dealer in your area, go let them hear the amp and ask them what they think. If you choose to, they can send the amp to Linn for you for service. If there is any repair needed, Linn will do it for a flat fee of $250.

Unless you are a really die hard DIY guy, I personally think it would be very wise to send the amp to Linn. In addition to fixing anything that is wrong, they will buff up the amp in other ways as well (for example typically they add any undocumented improvements that have occured in the product since yours was made).

If you are determined to do this yourself, try this question on pinkfishmedia.net. I think you will be able to get some advice there.