I-Tech Series

How can I-Tech produce so much power with only a 20A plug?

The combination of Class-I technology and an innovative PFC power supply enables I-Tech to very efficiently draw power from the A/C mains and deliver it to the speakers. This high efficiency, coupled with a significant amount of energy storage, allows I-Tech to deliver high power much more effectively than conventional designs, and thus reduces the demands on the power cord.

For more information, read this short "Tech Made Simple" article.

Also, to see real current draw numbers for I-Tech, refer to the AC Power Draw and Thermal Dissipation sheets here

Isn't Class-I just like other amplifier classes?

No, Class -I amplifiers are a fundamentally different design from all other amplifier classes on the market. Crown has patented the technology behind Class-I amplifiers and is the only manufacturer in the world building this design. 

For more information about Class-I, read this technical paper.

How does I-Tech recycle energy from the load?

Class-I is unique in that it always provides an electrical path between the amplifier's output and power supply bulk capacitors. This means that when a loudspeaker sends energy back to an I-Tech amplifier it stores it in the power supply for later use. This keeps the output devices from dissipating the energy from the loudspeaker as heat and keeps the power supply from having to work as hard.

Why is the I-Tech 2 ohm power number smaller than the 4 ohm power number?

The question may be better stated, "Why is the 4 ohm number so large?" The 4 Ohm number is so large because Class-I is not fundamentally voltage limited, unlike ALL other amplifier designs available on the market. Competitive amplifier designs require complicated multi-level (Class-H) supplies, which limit the voltage available to the output under low impedance loads. This multiple step supply topology lends itself to the typical power matrix. 

The down side of Class-H is that if the program material asks for a peak higher then the rail voltage limit the amplifier will distort. In other words, headroom is limited. Class-I does not exhibit this limitation. 200V is always available to all loads. As a result the amplifier is capable of producing very high music output peaks without distorting. 

Some view I-Tech's unconventional power matrix to indicate that I-Tech is not "good" or is "unstable" when driving low impedance loads. Nothing could be further from the truth. A fundamental advantage of Class-I is that it cares little about the load impedance. Pile on the speakers. I-Tech isn't afraid.

How does Crown measure power?

Output power is measured using the "Maximum Average Power" method. The Maximum Average Power test is designed to be an easy way to more closely approximate output power with real world musical sources. The test is simple: the amplifier is set up with the level controls turned to the maximum setting, and then a connected sine wave source is increased until the specified total harmonic distortion is reached.

What are your 20Hz to 20kHz specs?

All output power specs for I-Tech are provided at 20Hz to 20kHz.

I heard that PFC could cause the mains to sag and shut the amplifier down. Will I-Techs PFC do that?

No. I-Tech monitors the mains voltage and gently corrects for this rare phenomenon.

What kind of filters are available in I-Tech's DSP?

There are 64 filters total within the I-Tech DSP and they can be placed anywhere within the system. In addition to filtering,each possesses up to +/-24dB of gain. 

The following filters are available: 
Lowpass::Bessel 2-4,Butterworth1-4,and Linkwitz-Riley 4 
Highpass:Bessel 2-4,Butterworth1-4,and Linkwitz-Riley 4 
Lowshelf::Low-frequency shelving EQ 
Highshelf:High-frequency shelving EQ 
Lowpass EQ:Variable Q from 0.1 to 35 
Highpass EQ:Variable Q from 0.1 to 35 
Parametric EQ:Variable Q from 0.1 to 35 
All Pass:1st and 2nd order 

All Pass filters provide no gain change to the output, but provide a phase change at the selected frequency. This corrects the phase relationship of the output without a gain reduction, such as is found in other filters.

How many filters are available in I-Tech's DSP?

There 64 filters available in I-Techs DSP.

How much delay is available in I-Tech's DSP?

I-Tech has over 2 full seconds of delay available on each channel, adjustable in 20 microsecond increments.

What are the adjustment increments for I-Tech's delay setting?

One 48,000th of a second, or 0.02083 millisecond, or approximately 1/4" or about 1 centimeter.

Will other signal processors work with I-Tech? I don't want to use the on board DSP.

Yes, any outboard signal processing can be used with I-Tech. You must remember that all DSP has its own inherent latency and this must be considered when configuring delays.

Note: As in all cases with any amplifier, make sure you re-check the EQ for the room every time the system is setup in a different location. 

What is latency, and does I-Tech have a fixed latency?

The latency of a device is the amount of time it takes a signal to travel from the device's input to its output.

When using the analog inputs, latency has been measured at 1.13ms. The latency of the input/DSP section is fixed, and does not change whether using no processing or maximum- available processing.

Latency with an AES/EBU input varies due to buffering of the signal that occurs before it is sent to the input/DSP stage, and is dependent upon the input AES/EBU data rate as shown below:



32 KHz

2.744 ms

44.1 KHz

2.358 ms

48 KHz

2.275 ms

96 KHz

1.807 ms

In addition to these sources of delay through the amplifier, there is the possibility of some minimal delay due to the wiring of the AES/EBU signal. The AES/EBU standard 110Ω cable has a delay of 6ns/meter. In addition, the I-Tech amplifier has a delay of ~85ns in its active digital loop-thru. To put this in perspective, a system with 50 meters of cable and sixteen amplifiers all looped through each other would have a delay at the last amplifier of 1.575us. This is equivalent to a delay of less than one-quarter inch. This additional source of delay will be inconsequential in almost all systems and can be ignored.

Is post-processed audio available on the analog audio XLR outputs/loop through?

No. Since all I-Tech amplifiers have DSP as standard, post-processed outputs are not necessary.

I cannot find 26dB gain in the sensitivity menu. Is it available in I-Tech?

Yes, many different sensitivities and gains are available depending on the setting of the max input level switch. Refer to the I-Tech Application Guide for a complete list of all 149 sensitivity / gain settings. 

To set the I-Tech amp for 26dB gain, change the max input level switch to 20dBu using IQwic or the front panel display. Upon returning to the sensitivity menu you can set the gain to 26dB.

What is an attenuator limiter?

An attenuator limiter is a control set via the front panel display or through IQwic software that places a limit or lock on the attenuator at a user defined level keeping curious hands from turning the input attenuator beyond your desired level.

How do I set the power limiters on an I-Tech?

Via either the front panel LCD or IQwic software.

Why did you put an LCD on the front?

  • To provide real-time diagnostics: thermal headroom, load monitoring, etc. 
  • To provide much of the IQ Network capabilities without the need to set up a network. 
  • To make monitoring all this information easy.

Do I have to use the LCD?

No. The amplifier was designed for simple plug-and-play operation, and can be quickly setup as though it were a traditional amplifier.

How can I keep unauthorized people from tampering with my settings?

Controls can be fully locked out through front panel LCD or through higher levels of security using IQwic software.

I don't know anything about networking. Can I get I-Tech's networking up and running quickly without reading a book or taking a class?

In IQWic version 7, a network wizard is included under the Setup Menu to assist in the process of setting up your network. The software looks at your computer and configures the address of the amplifier to be on the same network. In many cases, this is all that is required to set up your IQ Network.

What happens if the network breaks or goes down?

Network communication will stop, but the amplifier will continue to operate as last programmed.

What happens if the amp loses digital signal?

The analog connections can be configured as backup and the amplifier will switch to those connections automatically.

Are there filters available for the air inlets?

Yes, two sets are included with the amplifier.

Are the air filters required? How often should I change them?

Although the amplifier is shipped with air filters, they are not required. If you use the air filters, you should clean or change them frequently depending on the dust level of the environment where they are used. The dust should not be allowed to block the airflow into the amplifier.

Why is the screen on the I-Tech 4x3500HD no longer a touch-screen?

Due to supplier issues with quality and delivery, we have removed the touch-screen capability from the I-Tech 4x3500HD. Several of the display screens and menus have been updated to accommodate this change. Performance of the I-Tech 4x3500HD has not been impacted by this change in any way.  If you have any questions regarding this issue, please contact our Technical Support team at support@crownaudio.com.