Hi, could you tell me where to find a guide to tune DT40 that have a year and very little use. The ones I have are the two drivers on a single board. I sent Jian from DT electronics an e-mail asking if there was a link of some adjustment manual and he answered no. And that he would not know how to explain to me how to do it. Then he suggested I buy a new DT50 directly and discard the DT40 .... what a shitty service !!. I live on the other side of the world of china and it is impossible to send them to tune it. I work in electronics for 25 years and never a technical service gave me an answer so son of a bitch. Never again a DT Electronics product. So,i know its no easy to do the tuning, but can anyone give me a link to an adjustment guide? A couple of years ago I saw in PL a link, but I can not find it. Thanks, from South America.