ASUS Essence One review

Opamps- NE5532P

The good ole’ 5532...rises again!  We would say this chip is the essence of the word generic but that is not to say it is not a good quality chip.  In fact this chip has been used in everything from high end recording mixers to modern receivers.

Equivalent Input Noise Voltage of 5 nV/√Hz Typ at 1 kHz, a Slew Rate of 9 V/ms Typ and a Unity-Gain Bandwidth: 10 MHz Typ.  This unit has a very familiar, analog flavor and sonic characteristics that have been heard and many major musical recordings over the years.  That being said, the unit is a little dated and we would say it was chosen for its performance to price ratio.

NE5532P Spec Sheet

Opamps LM4562NA/LME49720NA

We were not surprised to see the 4562 in this design as they are excellent opamps for the price point.

This unit offers an Input Noise Density 2.7nV/√Hz (typ) a fast Slew Rate ±20V/μs (typ), Gain Bandwidth Product 55MHz (typ) and an incredibly low THD+N of 0.00003%!

This unit offers excellent clarity and detail previously unheard in other opamps at this price point. We would say this chip was an excellent choice and gives the E1 a very refined, detailed profile.

Note: The E1 uses an LME49720NA also but these are identical chips. 

LM4562NA Spec Sheet - LME49720NA Spec Sheet

Head Amp Section

Opamp: LME49600

This chip is the headphone amplifier circuit’s current buffer.  The unit offers a very high Slew Rate of 2000Vµs (typ) and a low THD+N of 0.00003%.  Two of these units are used for the headphone amplifier section of the E1, offering one amplifier chip per channel.

Above is the single LME 49600 chip (Left) and (Right) we have the entire headphone amplifier section.

To clarify, the signal proceeds from the DAC to the I/V 5532 opamps to the LME49720NA and finally to the LME49600 for each channel (L&R). You can see the LME49720NA opamps and LME49600 layout above right. Such a component layout would improve channel isolation and crosstalk for the headphone output. Essentially, the signal is kept in dual mono mode from the DAC right to the headphone output, nice touch!

We had an associate bring over a set of HD650’s to the audio lab which requires amplification and the E1 seemed to have no difficulty in driving them properly.

LME49600 Spec Sheet  

Alpha Volume Potentiometers

The Asus Essence One uses higher end Alpha potentiometers instead of just cheap generic versions.  We were pleased to see these units and they are not cheap and have been used in various high end audio products including units from Benchmark.

Capacitors

We were very interested at which capacitors were used in this design and we were pleasantly surprised to see high end Wima FKP2 (above) and others such as Nichicon.