I found that my 99 reached it's potential at about 50 hours. My conversations with Mark & Mark of Rogue confirmed that the tubes which lead to the most improvement when rolled are the ones on the right (facing the unit). I've tried GE/NOS and found them too bright; Sylvania chrome dome red base WGTBs and they have a warm, rich sound. But by far my favorites are RCA WGTBs (blackbase and red lettering). Also I highly recommend adding the tube dampers from Herbies Audio Lab to all four tubes (about @ $12.00). Really clarifies the sound. Another significant improvement was the use of Black Diamond Racing cones (#3s) under the 99 with the cone tips pointing UP - again, another improvement in clarity and openness. The BDR Cones are on MDF which is on Vibrapods on top of a wooden cabinet. Finally, place something heavy on top of the 99 (about 5-10lbs will do - I use a small glass vase filled with lead shot and felt on the base to protect the 99)to dampen the cabinet vibrations (just try tapping on the cabinet top to hear the tinny ringing; after placing the weight on top the ringing stops and therefore cannot be transmitted to the tubes.
I know this sounds a bit obssesive but I'm a restless tweaker and these changes are relatively inexpensive. I have had all my perveived improvements verified by my wife in blind listening tests to try to remove as much tweaker's bias I might have introduced.
The 99 is a great prreamp, but the russian tubes really need to go.
Good luck
I know this sounds a bit obssesive but I'm a restless tweaker and these changes are relatively inexpensive. I have had all my perveived improvements verified by my wife in blind listening tests to try to remove as much tweaker's bias I might have introduced.
The 99 is a great prreamp, but the russian tubes really need to go.
Good luck