Miller Audio Ultimate Upgrade ST-70
I’ve been an audiophile since the late 70’s. I’ve always searched for the ultimate accuracy in sound which meant that vacuum tubes were never in my system other than a California Audio Labs CD player in the early 90’s. I don’t even remember which tubes were in this CD player. (It never sounded quite right to me.) Still, I decided I wanted a tube amplifier even if it only spent an occasional listening session in my main system.
I received my Miller Audio Ultimate Upgrade ST-70 on June 10th. It is a basic configuration with Auto Bias and a standard compliment of tubes chosen by Bryan Miller. This consisted of 3 N.O.S. 6SN7 and a matched quad of JJ KT-77. This unit is all new parts assembled by Bryan and not an upgrade of an existing Dynaco ST-70.
Because my experience dealing with Brian was exceptional I wanted to do a review. My comparison was to my current Benchmark AHB2 that I’ve been listening to for the past four years. It is not the only amp that I own but the only one that is used in my main system since receiving it.
Currently I’m using three Cryotone 6SN7 and matched quad of Psvane HorizonEL34. I’m using the Miller ST-70 to drive a pair of GR-Research Bully speakersthat I assembled. Yes my listening room is treated. I’ve played around withcables. I have power conditioners. I use digital and vinyl sources. I like listeningto music of all types but mainly Classic Rock. I do not want to be cured.
Laboring over what to describe in the review I realized that since receiving theMiller ST-70 I have averaged 30-40 hours weekly listening to Music. At the timeI’m writing this, August 29, 2025, I’m at around 400 total hours! In that 10+ weekspan the Benchmark AHB2 has been in the system for no more than 3-4 hours forcomparison purposes.
You don’t need or care to hear my adjectives about the amplifier and it’s musicality. Yes there are many of them. If you want to listen to music and a 35-40 watt amplifier will meet your needs, I can’t think of a more satisfying option than Miller Audio and the Ultimate Upgrade ST-70, especially at the price.