Jensen ATS50rx

Price & Contact: $499; 407-333-8900; www.jensenaudio.com
All measurements @ 14 volts unless otherwise specified
Frequency Response {4-ohm IHF Load 20 Hz to 20 kHz, 1kHz Ref.): +0.08 dB, –0.04 dB
L/R channel error max deviation 20 Hz to 20 kHz: N/A
Phase Response (4-ohm IHF Load 20 Hz to 20 kHz, 1 kHz Ref.): +5.2 degrees, –11 degrees
Signal-to-Noise Ratio (Below Rated Output, “A” weighted): –100 dB
Distortion at Rated Output @ 1 kHz: 0.07% @ 100 watts x 1
Output Power (resistive) minimum output 20 Hz to 20 kHz @ 1%THD+N (all channels driven into 4 ohms): 47 watts x 2 @ 14 volts, 38 watts x 2 @ 12.8 volts, 25 watts x 2 @ 10.5 volts
Output Power (resistive) minimum output 20 Hz to 20kHz @ 1%THD+N (all channels driven into 2 ohms): 77 watts x 2 @ 14 volts, 63 watts x 2 @ 12.8 volts, 40 watts x 2 @ 10.5 volts
Output Power (resistive) (1 kHz @ 1%THD+N, all channels driven into 1 ohm): 131 watts x 2 @ 14 volts, 109 watts x 2 @ 12.8 volts, 70 watts x 2 @ 10.5 volts
Output Power (4-ohm IHF Reactive Load @ 1% THD+N @ 60 Hz): 140 watts
Output Power (2-ohm IHF Reactive Load @ 1% THD+N @ 60 Hz): 266 watts
Crosstalk (Referenced to Rated Output, 20 Hz to 20 kHz): -35 dB
Damping Factor @ 100 Hz, 2 ohms: 178
Voltage for Rated Output: 194 mV to 7.9 volts
Idle Current Draw: 1 amp
Current Draw @ 1/3 Maximum Power: 19.5 amps @ 83.3 watts
Efficiency @ 1/3 Maximum Power: 31%
Power-Up Noise: 29.5 dB SPL
Power-Down Noise: 23.23 dB SPL

Max Output @ 1 kHz: 9.2 volts
Signal-to-Noise Ratio (Below Max Output, “A” weighted): –121 dB
L/R channel error (max deviation 20 Hz to 20 kHz): .05 dB
Output Impedance: 221 ohms
Crosstalk (Referenced to Max Output, 20 Hz to 20 kHz}: –80 dB
Crossover frequency: Variable from 55 Hz to 575 Hz
Crossover roll-off rate: 12 dB-per-octave (increases to 24 dB-per-octave on LP as corner frequency is raised)

		Jensen ATS50rx www.jensenaudio.com
		Jensen’s two-channel ATS50rx offers real-world power and great system flexibility.		Jensen ATS50rx Specs Price & Contact: $499; 407-333-8900; www.jensenaudio.com All measurements @ 14 volts unless otherwise specified Frequency Response {4-ohm IHF Load 20 Hz to 20 kHz, 1kHz Ref.): +0.08 dB, –0.04 dB L/R channel error max deviation 20 Hz to 20 kHz: N/A Phase Response (4-ohm IHF Load 20 Hz to 20 kHz, 1 kHz Ref.): +5.2 degrees, –11 degrees Signal-to-Noise Ratio (Below Rated Output, “A” weighted): –100 dB Distortion at Rated Output @ 1 kHz: 0.07% @ 100 watts x 1 Output Power (resistive) minimum output 20 Hz to 20 kHz @ 1%THD+N (all channels driven into 4 ohms): 47 watts x 2 @ 14 volts, 38 watts x 2 @ 12.8 volts, 25 watts x 2 @ 10.5 volts Output Power (resistive) minimum output 20 Hz to 20kHz @ 1%THD+N (all channels driven into 2 ohms): 77 watts x 2 @ 14 volts, 63 watts x 2 @ 12.8 volts, 40 watts x 2 @ 10.5 volts Output Power (resistive) (1 kHz @ 1%THD+N, all channels driven into 1 ohm): 131 watts x 2 @ 14 volts, 109 watts x 2 @ 12.8 volts, 70 watts x 2 @ 10.5 volts Output Power (4-ohm IHF Reactive Load @ 1% THD+N @ 60 Hz): 140 watts Output Power (2-ohm IHF Reactive Load @ 1% THD+N @ 60 Hz): 266 watts Crosstalk (Referenced to Rated Output, 20 Hz to 20 kHz): -35 dB Damping Factor @ 100 Hz, 2 ohms: 178 Voltage for Rated Output: 194 mV to 7.9 volts Idle Current Draw: 1 amp Current Draw @ 1/3 Maximum Power: 19.5 amps @ 83.3 watts Efficiency @ 1/3 Maximum Power: 31% Power-Up Noise: 29.5 dB SPL Power-Down Noise: 23.23 dB SPL Internal Crossover Max Output @ 1 kHz: 9.2 volts Signal-to-Noise Ratio (Below Max Output, “A” weighted): –121 dB L/R channel error (max deviation 20 Hz to 20 kHz): .05 dB Output Impedance: 221 ohms Crosstalk (Referenced to Max Output, 20 Hz to 20 kHz}: –80 dB Crossover frequency: Variable from 55 Hz to 575 Hz Crossover roll-off rate: 12 dB-per-octave (increases to 24 dB-per-octave on LP as corner frequency is raised)
		by Brian Smith

		The ATS50rx is a two-channel amplifier with power ratings of 25 watts x 2 or 100 watts x1 into 4 ohms, 50 watts x 2 or 150 watts x 1 into 2 ohms, and 75 watts x 2 into 1 ohm. Features include gold-plated connections, fan-forced cooling, high-level inputs, and an independent two-way crossover. The crossover’s low-pass section contains a bass boost circuit that is partially controlled via a wired remote. Bass boost center frequency, boost level, and the crossover’s low-pass output offer continuously variable controls. While housed in the amplifier’s chassis, the crossover has no internal connection to the amp’s input. Performance Performance from the ATS50rx was quite impressive. The amplifier section exceeds, and in some cases nearly doubles its published power ratings. The only test that gave the amp trouble was our resistive power response test with both channels driving 1 ohm. This is a real devil of a test that basically begins by slamming the amp up to full power at 20 Hz and holding it there for several seconds while the computer regulates the amp’s output to 1% THD+N. This amp simply wouldn’t produce a 20 Hz signal with less than 1% distortion while driving 1-ohm-per-channel. Keep in mind that 20 Hz sine waves at full power have choked many fine power supplies, and attempting it with a 1-ohm load only complicates the issue. To give the ATS50rx the benefit of the doubt, we ran a somewhat less demanding test that plots THD+N vs. Output Power at 1 kHz. The ATS50rx had no trouble with this test and probably wouldn’t have any problems with a “1-ohm” speaker load as long as you listen to music and not low-frequency test tones. Since the crossover in this amp is essentially a separate unit housed in the same chassis, we ran a batch of tests on it as a stand-alone unit. Although the circuit has no gain, it will pass a maximum of 9.2 volts at 1% THD+N and has a signal-to-noise ratio of –121 dB. The crossover frequency is variable from 55 Hz to 575 Hz with a 12 dB-per-octave roll-off. On the low pass side, the roll off increases to 24 dB-per-octave as the cutoff frequency is increased. Connections & Adjustments Connections to the ATS50rx’s amplifier section include RCA inputs, high-level input receptacle (with supplied harness), and 3/8-inch spade receptacles for all power and speaker connections. Adjustments to the amplifier consist solely of input sensitivity, with an adjustment for each channel. Connections to the crossover section include a telephone-style receptacle for the wired remote and RCA connectors for both the inputs and the high- and low-pass outputs. Crossover frequency and bass boost center frequency adjustments are located in the chassis while the wired remote controls bass boost level and low-pass output level. Installation The ATS50rx offers a surprising amount of installation flexibility. The crossover allows the option of piping either the high or low frequencies to the amplifier section, leaving the alternate output for another amp, or to use the crossover and amp sections independently. One of the big advantages in this type of set-up lies in keeping both crossover functions in one place, controlled by one knob. Trying to use the HP filter in one amp and the LP filter in another without test equipment or even remote adjustment can be a harrowing task. We’ve seen this type of crossover layout a few times in the past but not nearly often enough. Another neat option is the adjustable mounting feet. The amp’s heat sink has an extruded slot down each side. The adjustable feet have a protrusion that slides into this slot allowing you to place the feet anywhere along the length of the amp. The amp can also be installed with the non-adjustable mounting tabs that are part of the end plate stamping. With the end caps installed, these mounting tabs are hidden, so the amp appears to float about a quarter of an inch above the mounting surface. Overall, the ATS50rx is a pretty impressive little package. It has a great crossover, lots of installation flexibility, and drives reactive loads without complaint. In the real world, it’s hard to ask for much more.