how long of a break in for 17d3

I find the 17d series to be very detailed and accurate, but never warm or soft, if that is what you are looking for. With some components that already have a bit of an edge, they can tend to sound aggressive. I would have thought the Fosgate might tone that down some, but not so in your case. I am using a SimAudio LP5.3 with PX5.3 power supply which is dead silent even at high volumes, detailed but full sounding. Maybe try a step up transformer to the Fosgate instead of relying on it for the full amplification.

I think the Dynavector sounds fine, the output level is so low it makes you turn the gain on the preamp up enough to hear tube rush noise. The Fosgate has 60 db of gain so with only .3 mv from the Dynavector the gain is marginal.

I made a couple of changes. I put RAM super low noise tubes in the Fosgate which made a significant difference in the noise floor. I also bought a Shelter 901 with .5 mv output. I like the shelter better han the Dyna in most ways, but the Dyna is still a good cartridge.