Actually, I'm quite fond of the amplifier because:
- It provides a consistently good first impression
- It is well made
- He is pretty small (because class D and an external power supply - that is, however, larger than the amplifier :-)
- It is good to warm to my 16 Ohm speakers even at high volume (the power supply as well)
- The sound (also of the headphone output) is very good for my subjective feelings
So why only 2 stars?
There are two reasons.
1. The power supply whistles when the amplifier is in standby. So although I can well live, but here is a hi-fi equipment, there should not be. -1 Star.
2. In idle or quiet passages in the music, I hear a faint noise and hiss from the high and midrange my 3-way floorstanding speaker, which is still clearly perceptible even from 3 feet away. (Use the headphone output is not heard this noise.)
I also have a Pioneer AV receiver with Class-D amplifier, in which you can hear absolutely nothing when it is idle. -2 Star.
(I do not compare apples to oranges here, too, the Pioneer has 9 class D amplifiers for 400 Euro, the SMSL has 2 Class-D amplifiers for 120 Euro. As the Pioneer of the is what else he additionally provides per channel much cheaper .).
I have already begun the return and parallel to the amplifier again ordered because I am as I said actually very fond of the part. If the new amplifier no longer displays the error, I will adjust my review according to 4 or 5 stars.
I use the amplifier currently for two 4 ohm borne drivers (Bass Shaker - Bodyshaker) (one per channel) with a Y-cable to the subwoofer preamp my AV Receiver. Here the high frequency noise does not disturb also because the KSW not reproduce these high frequencies.
Here are a few metrics for power consumption:
The power pack alone without load: 0.7 W
Amplifier in standby: 2.2 W
Amplifier is idle on the 4 Ohm KSW: 5.2W
Phil Szymanowski describes in its 2 star review similar experiences on Amazon.com:
http://www.amazon.com/SMSL-TDA7498E-Digital-Amplifier-Headphone/product-reviews/B00NMCPTYA
Addendum: The second amplifier has arrived. - Short, unfortunately he rushes just like the first!
Full description: The very first measurement I made on a media player as a player with a 80cm stereo RCA cable. On a Pioneer Class-D AV receiver and a class AB amplifier NAD building produces no noise. Both SMSL Class-D amplifier noise as described above here.
Then I both SMSL amplifiers the RCA inputs shorted to the source and eliminate the cable as a noise source. The noise in the 16 Ohm 3-way speakers is still available unchanged. The noise level is also independent of the position of the volume control. Then I operated one of SMSL amplifier with an old linear regulated DC power supply. Again, the noise remains unchanged. The noise is (tested by 24V to 35V) independently of the input voltage. That is, the "cheap" 36V switching power supplies, which are supplied with the amplifier will be eliminated as the cause of the noise also. I've also tested a power cord with ground terminal, unfortunately without success.
I also sometimes a single 8 Ohm tweeter directly connected to one of the speaker outputs, also here can be heard the noise.
In the next few days I will return one of the amplifier and keep the second, because it with the body sound transducers (Bass Shaker - Bodyshaker) works well.
For music enjoyment on normal speakers of SMSL amplifier for me is not suitable. That should also the operational area for 99% of buyers be, so I'll stay with the 2 stars.
2. Supplement: (I deliberately destroyed the warranty seal to like to see the inside of the amplifier in order.)
The appendix pictures of the inner life of the amplifier, it is not considered quite the thing is in the product description and is displayed in the product photos. (It is not ALPS potentiometers and it doesn't install air coils.) For the one the customer something pretends here in the product description, I pull from another star. Power then a star.
Further images from the measured frequency response of the left and right channels with a Rohde & Schwarz UPV. Thus, the no ALPS Qualitätspotentiometer was installed, the channels are slightly different sound (0,45dB = 5.32% and 7.77% depending on 0,65dB = output power).
And then a few more screenshots of LeCroy HDO6054 (12 bit, 500 MHz) oscilloscope. The "needles" in the pictures is the switching frequency of the power supply or that which goes to the speakers as a disturbance. The switching frequency is not completely fixed, it varies by 20.6 kHz. It is well used "Spread Spectrum Clocking". The "triangular wave" is the switching frequency (308 kHz) of the TDA7498E. The measurements were made with an input signal of 1,41421Vpp with 991Hz at 4 ohms resistive load at the speaker output.