Followings were posted in other threads, and I do not know how to link without repeating here.
Teac NPH750 has been arrived, and burning-in process has been going on. I listen to it through He-6 connected to speaker taps. Out of the box, I can say that SQ is better than AH-01, it sounds fuller. With stock power cable the sound is not grainy. The amplifier section seems CLASS A, because the section was untouchably hot after 10 minutes of use. There are treble and bass control by remote control. The level control seems linear especially in Bass side. And it can tame He-6 with it. The DAC section is pretty good. Even though spec declares not impressive number like SN ratio of 85 dB and THD of 0.5%, but I do not believe the spec of the manufacturers in general. The important matters are inter-relations of the components, in these regards Teac NPH750 performs well unexpectedly. Teac declares the spec honestly, but they should declare the unit operating class A amplifier that headfiers are looking after. Everybody goes after very low THD and current mode driven amplifier for He-6. The consequence is very expensive amplifier to drive He-6. I think this unit can drive other high impedance headphones well. Noise floor is lower than Emotiva mini-X A100, with which my HE-6 sounds shrill and bright. This fact is very important, when high percentage of Emotiva mini-x For the moment NPH-750 sounds little bit bright. The remote control is well built and useful.
The details are there, and harsh has gone away when I changed from Aux1 input to internal DAC through optical input. This might be due to the elimination of interconnection, or good quality design around DAC chip PCM1975. USB connection requires some additional work of installing from Teac site for Windows 7 64 bit machine. The installing was flawless, and after that all is ok and sounds as the same sound signature as of optical connection. Head time is more with Teac NPH750 + He-6, than Conductor + LCD2.2. Temporarily Conductor has been decommissioned in favor of Teac NPH750. However it is not saying that Conductor is inferior, but it provides convenience of remote controlling with subtle difference of sound quality. It has very low noise floor as well. In Comparison with PM6005 of Marantz, I could not find specific fault so that I decided to stay with Teac H750 for the moment. Next thing is to replace the stock power cable with some low-priced Gaofei power cable to see some improvement.
Edited by Joong - 4/17/14 at 7:24pm
Shown above is analog amplifier section in discrete components with large heat sink.