Hi all, just ordered one of these to use as a headphone amp and also maybe a preamp or a valve buffer rather like the MF X10 (I think) but reading the emailed brochure it says not to be used with DC coupled power amps. If I connect the thing to a normal line input instead of the power amp input will this be okay and how do I know if the power amp in my integrated amp is DC coupled? The amp is a musical fidelity A3.5 with a tape loop.