Surround
The surround amplifier enjoys less popularity than the surround receiver and comes almost exclusively in the highest price ranges. Many electronics manufacturers have a wide range of surround receivers and topmodel as a surround amplifier. Theoretically, an amp sound better than a receiver because the power of the device have to be shared with the tuner. In addition, the signals in the amplifier is not influenced by the electronics of the tuner. Seek not the cream of the crop (and priced) and you do not want two devices only, then you're probably better off with a surround amplifier.
Power
The output power, in short, how much noise is coming from the amp. The more power the amplifier has the better this "the boss" over the speakers. A better controlled sound is the result. However, you must be careful when comparing to power amplifiers because manufacturers often use different methods. The channel number indicates how many speakers you can plug the amp in a surround setup.
THX Certified
When the device carries this mark, it means that it is capable of very realistic, unrivaled cinema sound to realize. Only the high-end amplifiers or receivers can have this view.
Turntable connection
Not all amplifiers have a connection for the turntable (phono). Some people attach great value to their (old) plates. If you're one of those people, pay attention to whether the desired amplifier does have such a connector. If not then you can always buy a separate phono voorversterkertje you connect eg aux input of the amplifier. For the discerning music lovers may even be wise to separate (better quality) phono preamp to use.
Speaker Selector
With this switch you can use the front speakers on and off. With a selector that only an A state may have a few front speakers on and off. With an A and B mode, it is also possible to use in a second space to connect a pair of speakers. You can then only a few speakers to play simultaneously. When switch A, B and A + B mode, you can also have both pairs of speakers simultaneously play. Additionally, you can in the latter case your front speakers bi-wiring, high and low tones are then connected with separate cables. Note that if you want to connect more speakers, the impedance of the speakers matches the recommendations of the amplifier manufacturer. Generally you need four speakers with an impedance of 8 ohms have to play them simultaneously. Have you, in the event that the speakers have a lower impedance, well informed before you connect all four speakers. A low impedance may cause damage to the amplifier.
Tone Control
Some manufacturers of amplifiers perform their devices without tone. This stems from the belief that sound as natural (as close to the original) may be displayed. A tone control in that respect is out of the question. However, for the average consumer very practical to the treble or bass something to ask.
Source Direct
This switch allows you an alternative (as short as possible) select signal in the amplifier. As example The tone control is beaten about the sound as natural as possible.
Dimensions
Often the dimensions of a particular device is not very carefully watched. If you do not want to customize existing audio rack or replace it is wise to do so! Surround amplifiers are generally much larger than stereo amplifiers. Especially the depth is greater.