Love seeing more of these amps out in the wild.
Anyone else getting hiss on dynamic headphones?
Yes I have hiss too.It is more like combination of Hiss and Humm together. In proportion Hiss/Humm as 70/30. Hiss is gradually increases with increase of Volume, but much slower (not like sound increases), while the Humm noise almost reminds on the same level and with Volume increase, suddenly start to distort (depends of RCA or XLR input selected) at 1 or 3 o'clock respectively. Right now I am using Sennheiser HD800S. Hiss/Humm on 4 pin XLR output in all L, M, H impedance positions. Hiss/humm starts to distorted when Volume at 3 o'clock (assuming that the Volume knob traveling from min 7 o'clock to max 5 o'clock position). I am using XLR input from DAC with max volume for me no more than at 9 o'clock position).
In my situation hiss/humm comes from all 1/4, pentagone, and 4pin XLR outputs. Looks like loud valves, but very noticeable when switching between headphone's outputs on minimal volume.
Control test: Unplug everything. No any inputs. Only Power cable. Sennheiser HD800S plugged in into 4 pin XLR output. Hiss starts on the last 2-3 actuators steps on each L,M, H impedances.
Next test: RCA input from DAC. Music on pause. Hiss starts from 1 o'clock volume position, very loud on maximum volume on each L, M, H impedances.
Next test: XLR input from DAC. Music on Pause. Hiss starts from 3 o'clock volume position, noticeable hiss when volume on maximum on each L, M, H impedances again.
RCA input gives the most loud hiss. Usually I am using XLR input and at volume at 9 o'clocks it is inaudible. Will play with better shielded RCA and XLR cables tomorrow.
Also will play tomorrow with Power filtering, DC blocker, Power filter conditioner, good shielded power cable and will do very short run/cable from DAC. may be 3.0inch XLR and RCA with extra shielding.
Also will do more tube burning may be 100 hours.
Will post my results here.
At this moment try to exclude any other reason of hiss.
