I liked Frank 845 amp much more than the bhse, although I only listen to the bhse through the sr-009 and did not use the sr-007
Currently there are three very good amplifier to listen to the Stax SR-009 and, also, the JPS Abyss and Audeze LCD3-F headphones.
To listen to the JPS Abyss and the LCD-3F headphones, go see the side of Viva Egoista
To listen to the SR-009, well, the DHT Franck Cooter amp, with 845 tubes, does not leave unmoved (ask to jude,
To listen to both the JPS-Abyss, the LCD3-F, but also the Stax SR-009, go to Munich (in 1 month) at the HIGH-END and listen to the amazing Audiovalve Luminare amp built by Mr. Becker.
Finally, to do justice to the SR-007 mk1 headphone (which is no longer produced), the BHSE amp is a good choice to those who wait two years (or more) of waiting for the order.