Coming up at around 60 hours now. Always sounds amazing, but I will say that some days sound better than others. With my schedule, it will take me a while to rack up the hours for burn in, and unfortunately being an all tube system, turning it on and closing the door for 2 weeks is out of the question. After 60 hours, there is very noticeable increase in micro detail and finesse, although as of late, I feel like the depth could be better. (Could Be the ref 6 still Burning in).......The roller coaster of burn in!
What strikes me all the time however, is how the the ref 75se can unravel complexities so much better then my previous DS450. It is an x ray of the soundfield but it doesn’t sound clinical. It’s musical. Not hi fi pyrotechnic sizzles and boom.
Incidental noises on recordings are more discernible. Chair creaks, coughs, etc..you can see these things very easily. It’s imaging that I’ve rarely encountered before, and it’s satisfying to have it finally in my own system to enjoy. These two pieces work extremely well together.
I do remember reading a thread about a member who was breaking in their ref 6 and complained about it being bass shy at times and being a little on the bright side. Someone had mentioned that’s some people only notice the preamp get better and better and wondered why some people got "schizophrenic ref 6’s". some people, were quick to be dismissive and state there must be something with his system for him to hear differences from day to day.
I wouldnt go that far with mine, but I do concur with OP stating they could hear differences as his ref 6 was burning in. I hear it as well.
I had the ref 6 for about six months before getting the ref 75se. I put about 200 hours on it before the ref 75. While the ref 6 was an obvious improvement on the Ls17, the ref 75se is to my ears, an even bigger improvement on the DS450. I would imagine because the ds450 and ref75 are different topologies all together, while the already tubed LS-17 is more of a scaled and stripped down version of ARC’s better Tube preamps.
The ribbons on the proacs with tubes is absolute magic. It’s true, ARC and ProAc are a phenominal match. Shout out to JohnnyR and his associates at audio connection in Verona, NJ for their guidance and help. Great place to audition this gear. Be prepared though, you may fall in lust.
My love for this hobby has been rekindled, for sure. I have so much old music rediscover and enjoy! Feeling quite blessed. 😌