Audio Horizons TP 2.0 Preamplifier

La45 I noticed improvements as mentioned in the first few days. But I also recommend leaving it on 24/7 playing a continuous CD source with amp off. After one week of this (168 hours) I noticed another leap in performance - thats when the big grin: "I know with certitude that I am keeping this preamp and it was worth every penny" happened for me.

My Siemens CCa's for #1&3 and gray plate early 60s 88cc's for 2&4, plus Herbies tubes dampers were installed today. I am ready to do some fun tube comparing. As I am new to tube rolling and I expect the diffences to be subtle, do any of you have suggestions on what to listen for, what music to use, how to AB compare etc?
My plan so far is to let them warm up for a hour but given they are all used tubes, start the project without a major breakin period. Also to use pieces like solo flute to check the body and harmonics of notes, and to use my other standard musical selections that I employ for comparing equipment. Any other hints, specific to tubes? Thanks. Joe

I'll let you all in on the tweak I'm going to do. It's not really a secret. I am going to try the V-Cap OIMP, oil-impregnated cap in place of the upgrade Hovlands that Joseph puts in as output caps in his upgrades. Out of curiosity, I asked Joseph if he had tried it and due to long break-in periods and cost, Joseph didn't have a chance to evaluate it, so I asked him if I could give it a try. He gave me the go ahead. If the cap seems that it has potential or proves overall superiority to the Hovland( by the way, a very nice sounding cap in Joseph's circuitry) Joseph could consider it as another upgrade option. Being a tweaker and curious about the V-cap's sonics, I couldn't resist hearing it in the preamp. I just ordered the V-Caps, so it will be a few days before I receive them and the caps will need an additional 200 hours of break-in to realize their potential. I'll give time to time impressions on this thread. http://www.v-cap.com/oilcapacitors.html

Joe, if your NOS Siemens tubes are indeed new, you'll need to allow another 24 hrs. or so for the new tubes to settle in. Please let us know what your impressions are.

Joe, what I heard, especially when putting in the Siemens CCa tubes in location 1 & 3 was a purer tonality of instruments. Pianos took on a more natural timber, with improved dynamics. Soundstage opened up and instrument placement seemed more exact. All instruments and human vocals just took on a more natural "aliveness" sound. The preamp is so precise that changing interconnects and power cords are easily discernable for fine-tuning the sound to please your ears. You are right, though, to listen to recordings that you are most intimate with to better gauge the differences.