Amplifiers > Amplifiers in your church sound system
Amplifiers in your church sound system
Amplifiers play an important role in your church sound system. After the sound has been mixed and equalized the signal is then passed on to the amplifier to power the main speakers. It is important to have a decent quality amplifier that matches the speakers in your system.
The power rating of your amplifier should be more than you will use, but not higher (or much higher) than the power handling capability of your speakers. With highly efficient speakers like the Electro-Voice FRX series which we often use in Churches, you really don't need a lot of power. For speech, you will probably use only about 10-20 watts. For live music in an average size church, you could get up to 50 - 100 watts. We often use the 7100 (below) as our main amplifier. It will deliver 200 watts in stereo, which is usually more than you need.
If your speakers have lower efficiency, you need a more powerful amplifier to get the same amount of volume as a high efficiency speaker with less power. For example 50 watts into a speaker system with a rating of 100 dB at 1 watt / 1 metre will give you the same volume of sound as 400 watts with a 91 dB at 1 watt / 1 metre.
Here are a few things to watch for when comparing power amplifiers:
1) When you look at power rating, make sure you are using the proper speaker impedance. Most speakers are 8 ohms.
2) If the amplifier is not located in a back room, fan noise is an issue. An amplifier with a quiet multi-stage fan and high efficiency is important.
3) Just because the amplifier says it can deliver a certain wattage, it doesn't mean it will do it continuously. Unfortunately you won't find this in the specs. We have bench tested some well known amplifiers which can only deliver under half their rated power for less than 20 minutes before overheating and shutting down. If you need continuous power, you need a good amplifier which really delivers what it claims.
Below are some of our favorite choices for amplifiers that we use in our church sound installations.
Electro-Voice 7100 Power Amplifier 
The Electro-Voice 7100 is a clean, quiet two channel power amplifier. It delivers 100 watts per channel into 8 ohms (150 into 4 ohms) with wide power bandwidth, low distortion and full load and amplifier protection. This makes it an excellent choice for live sound reinforcement in mid sized applications. Each channel has an independent gain control and balanced and unbalanced inputs.
The 7100 is the only amplifier in this price and power range which is convection cooled so there is no fan. This makes the amplifier very quiet and reliable. Many of the amplifier problems we repair are due to fan failure.
QSC ISA Series Amplifiers
The ISA 280 is a professional quality, dual channel power amplifier. It provides 185 watts per channel at 8 ohms, 280 watts at 4 ohms and 430 watts at 2 ohms. The ISA series comes with XLR and Barrier strip inputs and barrier strip outputs. Protection includes short circuit, open circuit, thermal, ultrasonic and RF.
ISA models range from 185 watts per channel up to 800 watts per channel into 8 ohms.
QSC RMX Series Amplifiers
The RMX Series of amplifiers are new from QSC. They give you clean, dynamic power with low background (fan) noise.
These amplifiers are available in several power ratings from 200 to 850 watts into 8 ohms (2000 watts into 2 ohms).
Crown CTS Series Amplifiers
If you want to move into the big league, The Crown CTS series lives up to Crown's reputation that can't be beat. We sometimes use the Crown CTS600 which delivers 300 watts into 8 ohms.
These amplifier are available up to 1250 watts into 8 ohms.
View Prices and Data Sheets for all power amplifiers in our web store.