Hello once again. I am pondering the purchase of a DMA 100 amp and a DMC15 preamp. Both of these units seem to be in good shape but are still over 10 yrs old. I'm thinking second system long term and would like any advice concerning repairs/maintenance to be done at the factory. I own new Spectral Gear so am still within warranty and have no experience with their service dept. I'm also thinking that maintenance is probably cheaper than repair. Any thoughts?