ati amplifier technologies inc
"ATI amplifiers are our specialty and the only products we carry"

Frequently Asked Questions

What is involved in upgrading an ATI amplifier to a unit with more channels?

The AT1800/AT2000/AT3000/AT4000/AT6000 Series amplifiers can be upgraded with more channels, but only within the same family. For example, an AT1802 can be upgraded to anywhere from an AT1803 to an AT1807. An AT4005 can be upgraded to an AT4006 or an AT4007. What this means is that if you purchase a 5 channel amp today and down the road you want to upgrade it to a 7 channel unit, you can do that. However, series cannot be upgraded, e.g. an AT1800 series amplifier cannot be upgraded to an AT2000 or an AT4000 series unit.

Units must be shipped back to the factory for the upgrade. The conversion is not designed to be done by the owner. In addition to amplifier modules being added, transformers and back panels may need to be replaced, based on the particular model and conversion required.

In addition, to the cost of the upgrade, the client is also responsible for shipping charges both ways. If and when you need to upgrade, contact ATI directly to initiate the process. Keep in mind that upgrading your amplifier in the future, will cost you more in total compared to if you had purchased an amplifier with the additional channels today.

Note that the AT520NC and AT540NC series cannot be upgraded.

If my speakers are rated at 150 watts, does that mean that a 180 watt amplifier is not the correct choice?

Not necessarily. A 180 watt amplifier simply means that the unit can output that much power, not that it will do so all the time. If you have speakers that can handle less power than the amplifier's maximum, that is fine. Just do not turn the volume control on your preamp/processor all the way up. The extra power capability will come in handy when you upgrade your speakers. It is also better to have an amplifier that has more power handling capability than not enough; this can prevent clipping and distortion when driven to brief, loud levels such as in action/adventure movies (crashes, gunfire, explosions etc).

I need a home theater power amplifier - what would you recommend?

Our most popular home theater amplifiers are the AT520NC, AT540NC, AT4000 and AT6000 series. The AT4000/6000 amplifiers can be upgraded with more channels (although it will cost you more due to the shipping charges to send the unit back to the factory for the upgrade). However, the AT520/540NC series are not upgradeable.

If you want to save $ today and will be happy with a 5 channel system for the next year or two, then choose the AT4005, AT525NC or AT6005. If you want to go with the best, know that you will probably be upgrading to a 7 channel system within the next couple of years or do not want to deal with the extra cost and hassle of shipping and upgrading the amp at a later date, then go with the AT4007, AT527NC or AT6007.

If you have inefficient speakers, a very large home theater, like to listen to your movies/music at extremely loud listen levels or just want a top-of the-line amplifier, then choose the AT6000 300 watts per channel Signature Series (AT6005 or AT6007) or a couple of amplifiers from the AT540NC series (500 watts per channel), e.g. an AT542NC and AT543NC for a 5 channel system or an AT543NC and AT544NC for a 7 channel setup.

The AT1800 series (180 watts per channel) provide an extremely good value for the cost conscience. If this is your first home theater power amplifier and you are on a tight budget, the AT1805 or AT1807 would be the way to go. They sound great, have lots of power and make a huge difference over the limitations of a (home theater) receiver with their lower output levels and other power amplifier compromises.

The AT4003, AT523NC and AT6003 are popular choices for those that just need a 3 channel amplifier to power the center as well as the left and right front speakers.

In addition to home theater, I also listen to music - how well will your amplifiers work in that application?

Our amplifiers are very accurate, sound clean and have plenty of reserve power. Many of our clients do listen to both music and home theater with their ATI amplifiers and enjoy them tremendously in either scenario.

All I listen to is music and/or movies from 2 speakers - what would you suggest in this situation?

If music is all that you listen to and you only require a 2 channel amplifier, then the AT1802, AT4002, AT522NC, AT542NC and AT6002 would all be very nice choices. Which amp you select would depend on how much power you need.

My speakers are rated at a "nominal 4 ohms" or "nominal 8 ohms" . What does this mean and will your amplifier work satisfactorily with my speakers?

The impedance of speakers changes slightly over frequency. A speaker rated at 8 ohms will actually vary slightly over the 20 Hz to 20 KHz range. Therefore the speaker manufacturers give a nominal impedance so as to give an approximate value. Sometimes this figure may be given at a specified frequency, e.g. 8 ohms at 1 KHz. Your 4 or 8 ohm speakers will work just fine with the various ATI amplifiers. There are no switches or settings that need to be adjusted for the particular impedance of your speaker. Just connect them and enjoy!

Does each amplifier module have its own power supply?

Each amplifier comes with two separate transformers. Each amplifier has its own power supply, i.e. bridge rectifiers, smoothing capacitors etc. These independent power supplies are fed from individual secondary windings from the transformers. This results in excellent channel separation, i.e. the individual channels do not "talk" to each other.

I notice that some of your amplifiers have balanced inputs. When would it be advisable to use them?

Only the AT2000, AT3000, AT4000, AT520NC, AT540NC and AT6000 series amplifiers have balanced inputs in addition to single ended inputs (RCA). If you are like most folks where the amplifier and preamp/processor will be within a short distance of each other and you will be using interconnect cables less than 10 feet, then RCA cables will typically be just fine. If the cables are going to be much longer then you may want to consider using the balanced inputs with the appropriate cables as this can help to reduce noise pickup on "long" cables. Since balanced inputs are quieter, then we'd recommend that if your preamp/processor has balanced outputs, then take advantage and use them regardless of the length of your audio interconnect cables.

How do I control the AT6012 multiroom amplifier and which wall plates/switches are you compatible with?

The AT6012 multiroom amplifier is controlled by a simple momentary rocker switch, such as the Leviton® 5657-2E. The switch is connected to the amplifier via a 3 conductor cable. The rocker switch (one switch per room) has the ability to increase and decrease the volume thus allowing each room to have its own independent volume control.

What kind of output trigger is provided on the processors to be able to turn on and off other devices such as power amplifiers?

A switched DC output is provided via a 3.5 mm (1/8") jack that becomes "live" with 12 volts when the processor is turned on and drops to 0 volts when the processor is turned off. This source of 12 volts DC would typically be used to turn an amplifier on and off. Make sure to use a mono (not stereo) 3.5 mm (1/8") plug to plug into the jack. The wires from the plug can be a small gauge (18 AWG to 26 AWG) as minimal current is involved. The wires would then connect to the device that is looking for this source of switched 12 volts DC, e.g. the input trigger on an ATI amplifier.

What kind of input trigger is provided on the amplifiers such that the amplifier can be turned on and off by other devices?

A 3.5 mm (1/8") input jack is provided that requires 12 volts DC to turn the amplifier on and 0 volts when the amplifier is to be turned off. This source of 12 volts DC would typically come from the output trigger of a preamplifier or processor. Make sure to use a mono (not stereo) 3.5 mm (1/8") plug to plug into the jack. The wires from the plug can be a small gauge (18 AWG to 26 AWG) as minimal current is involved. The wires would then connect back to the device that is providing the switched source of 12 volts DC, e.g. the output trigger from an ATI amplifier.

What type of plug is provided on the end of the AC power cord for the Signature Series and D Class amplifiers?

The AT4000, AT520, AT540 and AT6000 series all come with a standard 15 amp AC plug that will plug right into a regular 15 amp wall socket.

What type of internal power supply technology do the amplifiers utilize?

All of the ATI amps use fan-less linear power supplies. They are silent and produce no electrical noise. Switching power supplies are less expensive but are susceptible to being electrically noisy, can produce EMI (electromagnetic interference) and can conduct dirty power back into your home's 110 volt AC power system, adversely affecting your audio/video gear, computer and other sensitive electronic equipment.

How do I register my amplifier with ATI for warranty purposes?

You can register your amplifier simply by sending an email to or online at Include a copy of the invoice and serial number of your amplifier. This will activate your warranty.

For the amplifiers that can be upgraded in terms of number of channels, can I purchase the amplifier modules from ATI and do the upgrade myself?

No. The amplifier must be sent back to ATI and the upgrade will be performed by factory personnel.

I hear hum and/or noise coming from the speakers. What can I do to fix this issue?

If you have cable TV, try disconnecting the cable (the one that comes from the cable company) from the rear of your cable box. If the hum disappears, then you have a "dirty ground" on the cable. This problem can be eliminated by using an in-line video transformer between the incoming cable and the cable box, e.g Jensen Transformers VRD-1FF.

If, with all input sources removed from you preamp/processor/receiver (which is still connected to your ATI amplifier via audio cables) you are still experiencing hum/noise, try connecting a small gauge wire from the ground terminal of the amp to the ground terminal of your preamp/processor/receiver. By connecting both chassis together, this may eliminate the problem.

For the AT520NC series, what is the minimum current rating that my AC power circuit should have in order to drive the amplifier to full power with all channels driven?

15 amps for the AT522NC, AT523NC and AT524NC. 20 amps for the AT525NC, AT526NC, AT527NC, AT528NC.

For the AT540NC series, what is the minimum current rating that my AC power circuit should have in order to drive the amplifier to full power with all channels driven?

15 amps for the AT542NC. 20 amps for the AT543NC and AT544NC.

For the AT4000 series, what is the minimum current rating that my AC power circuit should have in order to drive the amplifier to full power with all channels driven?

15 amps for the AT4002, AT4003 and AT4004. 20 amps for the AT4005, AT4006 and AT4007.

For the AT6000 series, what is the minimum current rating that my AC power circuit should have in order to drive the amplifier to full power with all channels driven?

15 amps for the AT6002, AT6003 and AT6004. 20 amps for the AT6005, AT6006 and AT6007. Also, for all AT6000 units, both power cords are required to be plugged in for the amplifier to turn on, and the power cords need to be plugged into two separate circuits, with the aforementioned current ratings, in order to achieve full power.

Can I still use a 15 amp circuit if I do not have a 20 amp circuit?

Yes and it will not harm the amplifier. More often than not, 15 amp circuit(s) are fine as no soundtrack has typically full strength signals in all channels simultaneously.

I need more than 200 watts per channel for my speakers that have a 4 Ohm (or lower) impedance. Do you recommend using the AT540NC series?

No. You should use the AT6000 series.