LA Sound S835
www.lasound.com
A solid design and overall stability complement LA Sound's S835 4-channel amplifier.
LA Sound S835 Specs

Price & Contact: available at Sears stores nationwide; 626-961-9700; www.lasound.com
All measurements @ 14 volts unless otherwise specified
Frequency Response (4 Ohm IHF Load 20 Hz to 20 kHz 1 kHz Ref.): +0 dB, –.46 dB
L/R channel error (Max deviation 20 Hz to 20 kHz): .17 dB
Phase Response (4-ohm IHF Load 20 Hz to 20 kHz 1 kHz Ref.): +7.6 degrees, –25.5 degrees
Signal-to-Noise Ratio (Below Full Output, “A” weighted): –97.6 dB
Distortion at Rated Output @ 1 kHz: 6.9% THD+N @ 150 watts x 2
Output Power (resistive) minimum output (20 Hz to 20 kHz @ 1% THD+N, all channels driven into 4 ohms): 44.7 watts x 4 @ 14 volts; 36.5 watts x 4 @ 12.8 volts; 23.5 watts x 4 @ 10.5 volts
Output Power (resistive) minimum output (20 Hz to 20 kHz @ 1% THD+N, all channels driven into 2 ohms): 53.3 watts x 4 @ 14 volts; 44.2 watts x 4 @ 12.8 volts; 28.7 watts x 4 @ 10.5 volts
Output Power (4-ohm IHF Reactive Load @ 1% THD+N @ 60 Hz bridged): 144.8 watts x 2
Crosstalk (Referenced to Full Output, 20 Hz to 20 kHz): –43.4 dB
Damping Factor @ 100 Hz: 25
Voltage for Full Output: 194 mV to 1.85 volts
Idle Current Draw: .8 amps
Current Draw @ 1/3 Maximum Power: 23.3 amps @ 43.8 watts x 2
Efficiency @ 1/3 Maximum Power: 26.90%
Power-Up Noise: 18.6 dB SPL
Power-Down Noise: 45.6 dB SPL
by Brian Smith
The S835 is a four-channel amp rated at 60 watts x 4 into 4 ohms. Features include gold-plated connections, switchable high- and low-pass filters with selectable cutoff frequency, 18 dB of bass boost, and 12 dB of treble boost.

Performance
The S835 fared well during its ride on our test bench. The advertized specs are a bit optimistic, but the power ratings you’re left with add up to a strong, stable 40-watts x 4. That’s a real 40 watts x 4 too — not like the 40 watts x 4 you get in all of those high-powered head units, but that’s another story. The S835 offers good power supply isolation, stability at high output, and the ability to drive reactive loads. Overall, the S835 seems to be a good package worthy of investigation if you need a 4-channel amp.

Installation
Installation should be straightforward — LA Sound even includes hardware. The S835 is one of the more compact 4-channel amps that we’ve seen, and could possibly be mounted under-seat in a larger car.

Connections & Adjustments
Connections to the S835 consist of 5/16–inch spade receptacles for all power and speaker connections and RCA inputs for each channel. Adjustments include input sensitivity, bass boost, treble boost, 2–4 channel selector, and crossover mode select. The crossover cutoff points are rather unusual in that they aren’t complementary. The option for high-pass is 120 Hz or 80 Hz, and the low-pass is selectable between 100 Hz and 50 Hz. This would cause a dip in the overall system response in any configuration but bypass. Of course, if your car just happens to have a large resonance at 110 Hz or 65 Hz, today’s your lucky day.

Manual
The manual for this unit covers both the S835 and the S735 (the 2-channel version). Both subjects are covered reasonably well with system diagrams for several configurations. The biggest surprise came in the system design section. It actually says that speaker placement is the most important consideration for a great sounding system. This is absolutely correct, but you won’t find many amp manufacturers that are willing to print that little pearl of wisdom in their manuals. The truth shall set you free.