Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis

SOLD , now part of a Private Collection

The Audio Research SP-11 MKII is one of those iconic preamps that lives in the pantheon of high-end audio gear, revered by audiophiles as a milestone in hybrid design. Released in the late '80s, it represents a perfect fusion of tube warmth and solid-state precision, making it a timeless piece for those chasing that sweet spot between detail and musicality. If you're hunting for a piece of audio history that still holds its own today, this beast should be on your radar.

*Ships by private courier in 2 boxes (original ARC boxes)

Production
1985
Condition
9.5/10
Serial No.
77034011
Factory Specs

FREQUENCY RESPONSE
High level input: ±1dB 0.2Hz to 100kHz. -3dB below 0.1Hz and above 200kHz. Phono input: ±.2dB of RIAA 20Hz to 40kHz. ±1dB of RIAA 1.0Hz to 100kHz.

DISTORTION (THD)
Harmonic distortion: Less than .005% at 2V RMS output, 5Hz to 20kHz (Typically less than .001% at midband, phono or line input). Intermodulation distortion: Less than .003% at 2V RMS output

NOISE & HUM
IHF weighted, shorted input: Output (Gain down): 6µV (110dB below rated output). Input (High level): 3µV equivalent input (110dB below 1V input). Phono: 0.15µV equivalent input (76dB below 1mV input)

GAIN
At 1kHz, bypass mode: Phono input to tape output: 46dB (0.2V output from 1mV input). Phono input to main output: 75dB (0.175mV input for 1V output). High level input to main output: 29dB (36mV input for 1V output).

INPUT IMPEDANCE
Phono: Front panel selectable 47K, 100, 30, 10, 3 ohms. Phono input capacitance: 150 pF at 10kHz. High level: 20K ohms or higher, depending on switch functions.

OUTPUT IMPEDANCE
250 ohms main, direct, inverted outputs. 500 ohms tape output. Recommended load 60K ohms and 100pF (20Kohms minimum, 1000pF maximum)

OUTPUT POLARITY
Tape outputs, direct output: Non-inverting. Invert output: Inverting. Main outputs (2): Selectable non-inverting or inverting. All outputs may be used simultaneously.

MAXIMUM INPUTS
Phono: 350 mV RMS at 1kHz, 1200 mV RMS at 10kHz (0.1 second maximum duration, 6dB less if continuous). High level: 25V RMS.

RATED OUTPUTS
2V RMS 1Hz to 100kHz main, direct, inverted outputs. (Maximum 80V RMS at 0.2% THD at 1kHz into 60kOhm load with 2.85V RMS high level input).

TUBE COMPLEMENT
(6) 6DJ8/ECC88

POWER REQUIREMENTS
95-135VAC 60Hz, 190-270VAC 50/60Hz, 130 Watts maximum

DIMENSIONS
(Each chassis, EIA Rack panel mounting) 19" (48 cm) W x 5 ¼" (13.4 cm) H x 10 ¼" (26 cm) D. Handles extend 1 ⅝" (4.1 cm) forward of panel. Interconnect cable extends 4" behind rear of chassis.
WEIGHT
SP-11: 14 lbs. (6.4 kg) Net, 23 lbs. (10.5 kg) Shipping.
SP-11PS: 15 lbs. (6.8 kg) Net, 23 lbs. (10.5 kg) Shipping.
Total: 29 lbs. (13.2 kg) Net, 46 lbs. (21.0 kg) Shipping.


 

The History of Audio Research
Audio Research Corporation, affectionately known to fans as ARC, was founded by William Z. Johnson, who began designing custom audio electronics in the early 1950’s and who also operated a specialty audio retail store until the mid-1960’s. Johnson’s efforts almost single-handedly revived vacuum-tube designs at a time...
[ Read More ]
Stock No.
8796842229981

The Audio Research SP-11 MKII is one of those iconic preamps that lives in the pantheon of high-end audio gear, revered by audiophiles as a milestone in hybrid design. Released in the late '80s, it represents a perfect fusion of tube warmth and solid-state precision, making it a timeless piece for those chasing that sweet spot between detail and musicality. If you're hunting for a piece of audio history that still holds its own today, this beast should be on your radar.

*Ships by private courier in 2 boxes (original ARC boxes)



Production

1985

Condition

9.5/10

Serial No.

77034011

Factory Specs

FREQUENCY RESPONSE
High level input: ±1dB 0.2Hz to 100kHz. -3dB below 0.1Hz and above 200kHz. Phono input: ±.2dB of RIAA 20Hz to 40kHz. ±1dB of RIAA 1.0Hz to 100kHz.

DISTORTION (THD)
Harmonic distortion: Less than .005% at 2V RMS output, 5Hz to 20kHz (Typically less than .001% at midband, phono or line input). Intermodulation distortion: Less than .003% at 2V RMS output

NOISE & HUM
IHF weighted, shorted input: Output (Gain down): 6µV (110dB below rated output). Input (High level): 3µV equivalent input (110dB below 1V input). Phono: 0.15µV equivalent input (76dB below 1mV input)

GAIN
At 1kHz, bypass mode: Phono input to tape output: 46dB (0.2V output from 1mV input). Phono input to main output: 75dB (0.175mV input for 1V output). High level input to main output: 29dB (36mV input for 1V output).

INPUT IMPEDANCE
Phono: Front panel selectable 47K, 100, 30, 10, 3 ohms. Phono input capacitance: 150 pF at 10kHz. High level: 20K ohms or higher, depending on switch functions.

OUTPUT IMPEDANCE
250 ohms main, direct, inverted outputs. 500 ohms tape output. Recommended load 60K ohms and 100pF (20Kohms minimum, 1000pF maximum)

OUTPUT POLARITY
Tape outputs, direct output: Non-inverting. Invert output: Inverting. Main outputs (2): Selectable non-inverting or inverting. All outputs may be used simultaneously.

MAXIMUM INPUTS
Phono: 350 mV RMS at 1kHz, 1200 mV RMS at 10kHz (0.1 second maximum duration, 6dB less if continuous). High level: 25V RMS.

RATED OUTPUTS
2V RMS 1Hz to 100kHz main, direct, inverted outputs. (Maximum 80V RMS at 0.2% THD at 1kHz into 60kOhm load with 2.85V RMS high level input).

TUBE COMPLEMENT
(6) 6DJ8/ECC88

POWER REQUIREMENTS
95-135VAC 60Hz, 190-270VAC 50/60Hz, 130 Watts maximum

DIMENSIONS
(Each chassis, EIA Rack panel mounting) 19" (48 cm) W x 5 ¼" (13.4 cm) H x 10 ¼" (26 cm) D. Handles extend 1 ⅝" (4.1 cm) forward of panel. Interconnect cable extends 4" behind rear of chassis.
WEIGHT
SP-11: 14 lbs. (6.4 kg) Net, 23 lbs. (10.5 kg) Shipping.
SP-11PS: 15 lbs. (6.8 kg) Net, 23 lbs. (10.5 kg) Shipping.
Total: 29 lbs. (13.2 kg) Net, 46 lbs. (21.0 kg) Shipping.


 

The History of Audio Research

Audio Research Corporation, affectionately known to fans as ARC, was founded by William Z. Johnson, who began designing custom audio electronics in the early 1950’s and who also operated a specialty audio retail store until the mid-1960’s. Johnson’s efforts almost single-handedly revived vacuum-tube designs at a time...
[ Read More ]

Stock No.

8796842229981

Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis
Vintage / Audio Research SP-11 MKII // Hybrid Tube Preamplifier / Dual Chassis

May We Suggest

Accuphase E-3000 / NEW // Integrated Amplifier

Accuphase E-3000 / New // Integrated Amplifier

MSRP $8,975
Aragon 4004 MKII // Vintage / Dual Mono Solid-State Amplifier / Recapped (051094)

Aragon 4004 Mkii // Vintage / Dual Mono Solid-state Amplifier / Recapped (051094)

$1,499
Aragon Palladium // Vintage / Solid-State Monoblock Amplifiers / Balanced Inputs / 030206/030207

Aragon Palladium // Vintage / Solid-state Monoblock Amplifiers / Balanced Inputs / 030206/030207

$2,999
Aragon Palladium // Vintage / Solid-State Monoblock Amplifiers / Balanced Inputs / 030322/030323

Aragon Palladium // Vintage / Solid-state Monoblock Amplifiers / Balanced Inputs / 030322/030323

$2,999
Aragon Palladium // Vintage / Solid-State Monoblock Amplifiers / Balanced Inputs / 030324/030325

Aragon Palladium // Vintage / Solid-state Monoblock Amplifiers / Balanced Inputs / 030324/030325

$2,999
Aragon Palladium // Vintage / Solid-State Monoblock Amplifiers / Balanced Inputs / 030446/030447

Aragon Palladium // Vintage / Solid-state Monoblock Amplifiers / Balanced Inputs / 030446/030447

$2,999
Audio Hungary Qualiton A75i // New / Integrated Amplifier / Silver

Audio Hungary Qualiton A75i // New / Integrated Amplifier / Silver

$9,250
Audio Innovations 500 // Vintage Integrated Tube Amplifier

Audio Innovations 500 // Vintage Integrated Tube Amplifier

$1,599
Audio Refinement Pre 5 // Vintage Solid-State Preamplifier

Audio Refinement Pre 5 // Vintage Solid-state Preamplifier

$899