audio research

Tube stereo line stage.

From the ARC website

After a successful run of more than three years, and with the introduction of more advanced preamps like the LS25 and REF2, it was time for a successor to the LS15. This new model -- the LS16 Stereo Vacuum-Tube Preamplifier -- offers superior performance, greater flexibility and more intuitive controls.

Chassis size and appearance are almost identical to the previous LS15, with the same complement of balanced / single ended inputs and outputs. The only major operational change is that the "Direct" input path of the LS15 is now a single-ended, unity-gain processor pass-through, a feature also included on the LS25 and RE F2. Incorporation in a home theater while preserving great two-channel sound is easier than ever. Input selections have been relabelled to include CD BAL, Phono, Tuner, Aux SE and Aux BAL.

Two additional mechanical changes deserve mention. Toggle switches are now the bidirectional spring-loaded type used on the more costly LS25. And the microprocessor-controlled volume control is also the same as used on the LS25, with a total of 104 individual steps. Both of these changes add greater control flexibility and a higher-quality operational feel.

Inside the LS16, you will find a new Class A gain circuit using four 6922 twin triodes with our proprietary clear damping rings, plus greater energy storage, the latest Infinicaps and improved power-supply regulation. The result is a sonic presentation that goes way, way beyond the LS15! Highs are better defined with a finer grain structure and less electronic hash, the midrange is more pure and open, while bass control, extension and dynamics are vastly improved from the LS15. Overall, there is much greater musical and tonal coherence from top to bottom, while definition of musical structure is more vivid and natural. This wonderfully balanced preamplifier mates extremely well with every vacuum-tube and solid-state amplifier we've tried.

Once you hear it, you will agree that the LS16 represents a new threshold of value for high-end audio preamplifiers, combining versatile features and improved sonic performance. Because of the many improvements and changes, it is not possible to update an LS15 to the LS16 configuration.



LS16 MKII (2001)

From the ARC website

Since its introduction in 1999, the LS16 has been a best-seller, combining a relaxed, engaging musicality with good flexibility and connection options. So why change a good thing? Well, the enhancements introduced in the Mark II versions of both the Reference 2 and LS25 have proven so popular that we feel it is time to incorporate many of the same technological improvements into the LS16MKII.

Functionally the LS16MKII remains unchanged except for the labeling of the inputs. (Single-ended inputs are now labeled CD, Tuner and Aux; Balanced inputs are labeled Bal 1 and Bal 2). The only other external change is the rear-panel addition of a 12V on/off trigger for remote powering of other linked audio and video components.

Internally the LS16MKII closely follows the evolutionary path established by the LS25MKII - and to a great extent the Reference 2 MKII - by incorporating a JFET input stage followed by a cathode-follower/output driver stage utilizing two 6H30 twin-triodes. Now all three preamps use the same wonderful output driver tube, rated to have an estimated service life of up to 10,000 hours.

Sonically the MKII is a compelling musical step forward, with greater resolution and purity. Everything sounds "faster" with less smearing. There is greater transparency, with better dynamic shading. Images are more precisely focused within an even larger and more holographic soundstage. And bass definition, control and impact are improved significantly. You will love the immediacy and refined musicality from the newest little brother of the Reference 2 MKII.

The MKII update is available to original units as a factory upgrade. New 6H30 tubes with our proprietary clear damping rings are included.


MSRP (US new retail)
$3,495 (LS16 MKII)


Frequency response ±.1dB, 1Hz to 60kHz at rated output. -3dB points below 0.5Hz and above 100kHz
Distortion (THD) .01% at 1V RMS Balanced output
Noise & hum 25µV RMS residual IHF weighted Balanced noise output with gain control with gain control at minimum (98dB below 2V RMS output).
Gain Main Output - 12.2dB unbalanced
Tape output - 0dB
Input impedance 150K ohms Balanced. 75K ohms SE . Inputs (7): AUX SE, PHONO, TUNER, CD BAL, AUX BAL, MONITOR (SE), and PROCESSOR (SE).
Output impedance 600 ohms Balanced, 300 ohms SE Main (2), 40K ohms minimum load and 1000pF maximum capacitance. Outputs (4): 2 Main Bal, 1 Main SE, 1 Record SE.
Output polarity  
Maximum inputs 14V RMS maximum Balanced (7V RMS SE)
Rated outputs 2V RMS (1V RMS SE) into 200K ohm Balanced load (maximum Balanced output capability is 30V RMS at 1% THD at 1kHz).
Power supplies Electronically regulated low and high voltage supplies. Automatic 45-sec. warmup mute. Automatic brown-out mute.
Tube complement :LS16: (4) 6922/E88CC dual triode
  LS16 MKII: (2) 6H30 dual triode
Power requirements 100-135VAC 60Hz (200-270VAC 50/60Hz) 45 watts maximum.
Other Controls: Volume, Input Select. Toggle switches: Power On/Off, Operate/Mute, Monitor/Input, Processor/Input. All functions on Remote Control.
Dimensions 19" (48 cm) W x 5.25" (13.3 cm) H (standard rack panel) x 10.5" (26.7 cm) D. Handles extend 1.50" (3.8 cm) forward of front panel.
Weight 11.9 lbs. (5.4 kg) Net; 21 lbs. (9.5 kg) Shipping.