Unless you are talking about the GFP-750, be wary of expensive upgrades to Adcom preamps. You'll quickly find yourself throwing money at products with limited performance potential and poor resale value. "Reasonably priced" and cottage industry audio modifications don't co-exist in the same universe. If someone has the skills to experiment along these lines without incurring labor charges, fine, go for it. But if you are paying someone to do these mods to a mid or lower level adcom product, you might as well pour money down a hole IMO.
moding and the inexperienced
hi,i'm looking at adcom preamps and from reading alot of posts have begun to be curious about it better caps transformers etc.but i have no elelectrical experience to figure any of this out.does anyone know of some good firms thet do mods for you and are reasonably priced?