my sl 1210 is louder on the right channel

having checked alignment, vta, bias, tracking force and everything else i just feel underwhelmed at it's performance it's not as clear on the left channel although sometimes there's more on the left but it just seems a bit muddy to me could it be the often quoted bad quality phono leads or should i just take it back to the shop for an exchange as i really want to keep this deck but it is peeing me off at the moment. Thanks for your help, Engine.