I understand this thread is for an Aurender N200 but since you asked, and since the esteemed @blisshifi responded, I will throw my 2 cents in. I just got a Rogue RP-7 preamp. It is very clear and resolving, but I find with the stock tubes the sound is bright and glaring in my system, to the point I have to wear sunglasses while listening. @blisshifi recommended the Brimars and Mullard NOS tubes to me, among others. Mullards are coming Wednesday, and I can report back if interested.
Robert