My build is complete, and I've been listening to Sennheiser HD650s all evening with expected results. Very enjoyable. Need to let it burn in for a while but definitely don't feel like I need to go rolling tubes, it sounds pretty excellent right out of the box. I did have two cold solder joints that I found during the final check before powering up and everything is rather ideal - balance seems perfect, all volume settings behave as expected, all the voltages were as expected. None of the other problems reported are here.
I have a question about the resistance across the inputs.
I have Crack and a Stereomour - each with a 100k volume pot and 100k input impedance. I've added an additional set of RCAs on to my Stereomour that allows me to connect the Crack in parallel with whatever Stereomour input is selected - reducing the input impedance to 50k. Paul Joppa said this was fine. It allowed me to switch between headphones/speakers without wiring anything around and select the input on my headphone amp easily with the Stereomour selector.
However, I've noticed that the Mainline input impedance is between 20k and 40k depending on the position of the fine attenuator (coarse attenuator doesn't matter). Meaning, if I connected it to my 'aux output' on the Stereomour as I did the crack, the input impedance could be as low as 16k for the system.
I suspect my SACD player and streamer can handle that as they are newer solid state devices and are probably not picky, but my phono stage is a Seduction, which if I recall was designed around 50k input impedance.
So what happens if I hook up a device to something with input impedance this low and the device can't handle it? Is it a risk for any of the equipment or just potentially a reduction in performance? Can the seduction (w/ C4S) handle that low 16k input impedance? Is there any risk to connecting it this way?