Went with the TP-41.
hopefully will be here in a couple weeks?
Don't know if this helps you Richard, here's some info I found:
The 41 doesn't have USB... it's not for me anyway.
Details
Topping TP41 T-Amp TA2021B Digital Amplifier & Headphone Amp
Feature:
T-Amp:
Tripath TA2021B
Output Power 2 x 25W @ 4ohm, 2 x 14W @ 8ohm
Signal-to-Noise Ratio (SNR) 100dB
Dynamic Range 100dB
IHF-IM Distortion 0.1% @ 1W, 4ohm
THD Distortion
0.05% @ 13W, 4ohm
0.1% @ 15.5W 4ohm
10% @ 25W 4ohm
10% @ 14W 8ohm
Headphone-AMP
Output Power 2 x 60mW @ 16ohm, 2 x 120W @ 32ohm
THD Distortion
0.01% @ 100mW, 32ohm
HIFI Electronic Components:
TOKO digital amplifier Inductance
ALPS Potentiometer
KOA Resistance
nichicon FW Capacitance
ERO Capacitance
EPCOS Capacitance
OMRON Relay
Panasonic Relay
Power input
220V-230V or 100V-110V
Audio input
Audio IN RCA (Left/Right) x 2, Auto or Manual selection
Output
Speaker OUT (Left) x 1 pair (+ / -)
Speaker OUT (Right) x 1 pair (+ / -)
Headphone OUT(6.35mm) x 1
Dimensions
about (W)155mm x (H)60mm x (D)280mm
Net Weight
2.5kg
http://www.houseofdap.com/topping-tp41-t-amp-ta2021b-digital-amplifier-headphone-amp.html