[PhilS]

I just obtained a set of AKG K701's. I am using them with a Singlepower Supra amplifier, which was voiced for the Senn HD 650's. With the HD650's, I achieve my typical listening volume at about 9:00 on the volume control on the amp, while with the K701's, I have to turn the volume up to about 11:00. This surprised me, given the lower impedance of the K701's. I know sensitivity factors into this as well, but from a rather technical thread I read about a month ago on impedance and sensitivity, it seemed that the volume setting for both cans would be roughly similar. Perhaps it's related to the Singlepower tube amp I am using.

In any event, I am wondering if anybody has any explanation for this, or if anyone using any of the Singlepower amps that were voiced for the Senn headphones have experienced the same thing.

 

[humanflyz]

It could be that the tubes on your Supra don't put out enough current for the K701s, which require a lot of it. I'm guessing you are using 6SN7s as output tubes? If so, you should try the 5687 or the 6BL7s, which give much more current than the 6SN7s.

 

[Jam_Master_J]

It's just sensitivity. The k701s low sensitivity is still enough to make it hard to drive despite it's low impedance. My DT880s were even a little easier to drive than the k701s on my amps.