I’ve been busy: On Tuesday I listened to it in the shop and I also did a very quick comparison with the amp in Sennheiser’s HDVD 800. I then spent yesterday plus the night before and the night after listening to it at home, comparing it with my Bryston BHA-1 and I also compared the Toxic Silver Widow cable (used on the Stockholm High End Show) with my Red Astrachan cable. Thank you Michael at Klutz Design for lending me the cable! I also did a quick listen with HD800 and HE6. So now I’m tired!
I’ll make a write-up of my findings when I have the time. I can give away this much though:
Now I’m the proud owner of one of the first production HPA-21s!
And most of last month’s salary is gone…
Meanwhile Q&A with CanDude and Soo In continues!
Q: Concerning the question on balanced output I did not mean that there is a problem with noise reduction. What I was referring to was that for a so called “balanced” headphone output both channels are totally separated and each channel has its own ground or minus connection (normally a 4-pin XLR is used), as opposed to an “unbalanced” or "single ended" headphone output where both channels share the same ground. Maybe this is not a problem in a current driving amp? Doesn’t the current for the two channels “affect” each other in some way via the common ground? Even though the output resistance is 2.5MΩ, does the movement of the voice coils still generate any current, altering the movement?
A: The balanced driving methodology is effective when the ground is not clean or not precise enough. Our SATRI Circuit's ground impedance is very low and highly precise so that the circuit performs better than the balanced driving method.
Q: When the battery runs out of power, does HPA-21 automatically switch to recharge mode, or do I manually need to turn off the power switch to start recharging the battery? Not used to battery power, I will forget to turn it off and the next day the battery will be empty if it is not automatically recharged.
A: When the battery runs out of power, it switches off automatically but does not star to charge automatically. You still have to manually turn off the power switch as the recharger only begins charging when the switch is physically at the off position. This method is to minimize the recharger interference during the play time.
I can add that I think I’ve already learnt to switch it off while I’m not listening. The battery recharger has a handy LED that is green while not charging and turns red when charging the batteries.
Edited by CanDude - 5/2/13 at 6:13pm