Atma-Sphere MP-3

Hi-End tube preamplifier featuring Balanced Differential Design®

The MP-3 preamplifier is based on the concepts pioneered by our MP-1 preamp in a single chassis. Recently updated to Mk 3.3, the MP-3 is a fully differential all-tube preamplifier with a direct-coupled high current output capable of driving low-impedance balanced-lines. The MP-3 easily drives interconnects over 200 feet long! The MP-3 extracts more ambient information with greater image specificity, bass definition and dynamic range than any single-ended preamplifier, owing to its patented direct-coupled output. Furthermore, it perfectly complements the balanced design of our amplifiers or any balanced power amplifier. The patented innovations, developed specifically for this preamplifier, make the MP-3 one of the best preamps made today.

Balanced line technology has been in use in the recording and broadcast industry for decades, and is why the high fidelity era began in the early 1950s, long before exotic interconnects existed. Balanced lines sound better than single-ended cables; are dramatically more resistant to RF, hum, cable artifact and cable length. The low impedance balanced line system is a means of preventing interconnect cables from having a sonic signature. The MP-3 supports this system, so you can run long cables with no need for exotic interconnects and still get exemplery performance.

In addition to its remarkable line section, the MP-3 works well with low-output moving coil cartridges and uses a minimum of connections in the front panel wiring and controls. A low number of gain stages (only three from phono input to line level output) insures low distortion, wide bandwidth and superb dynamic range. The result is a truly musical package of exceptional value.



– Balanced Differential Design®
– XLR connectors for phono and auxiliary inputs (paralleled RCA inputs optional)
– Regulated high voltage standard with Mk3.3 iteration (this used to be a $700 option)
– Two stage Constant Current Sources for each stage of gain (improves performance of each gain stage)
– Dual XLR outputs standard (RCA outputs optional)
– Patented direct-coupled Circlotronic® output
– Zero feedback design throughout

– Balanced differential passive phono equalization
– Precision 23 position stepped volume control built with 96 resistors on a custom built switch
– Two tape monitor inputs, tape functions use RCA jacks
– Precision components used throughout
– Total system phase switch
– Low-noise “star” grounding topology
– Additional options; click on ‘Order’ above
– Three-year general coverage warranty with one year warranty on output tubes
– Additional options on request


Line stage frequency response:

1 Hz-200 KHz, +0 dB, -2dB

Line stage gain:

15 dB

Line stage input impedance:

100 Kohm Ω single-ended / 200 Kohm Ω balanced

Line stage output:


Output impedance:

250 Ohms from 2Hz to 400KHz

Phono stage input impedance:

47 K Ω, adjustable with rear panel loading strip

Phono stage input overload:

500 mV

Phono stage max output:

( at clipping ) 120 V peak-to-peak

Phono stage gain:

55 dB

Phono bandwidth:

0.5 Hz-90 KHz within ½ dB

RIAA accuracy:

Within .1 dB

RIAA Phono sensitivity:

( for 0.5 V @ 1 KHz ) 0.2 mV

Power Supply storage:

50 Joules

Tube complement:

7 x 12AT7

2 x 6SN7GT:

2 x 12AU7


13″ deep x 17″ wide x 5.5″ tall ( 33 x 43 x 14 cm )

Faceplate dimensions:

( standard 3U rack, sans mounts ) 19″ wide x 6″ tall ( 48 x 15 cm )


Three years, transferable
One year for tubes


19 lbs. ( 8.6 kg )

Optional Features

V-CAP Copper foil capacitors for line stage
V-CAP Copper foil capacitors throughout
Caddock resistor package
Caddock volume control
Low output Moving-Coil step-up transformers
for cartridges under 0.2 mV
Damping package
Switchable Tape head input with EQ

Front Panel finish options

Brushed Gold (Anodized)
Custom panel finishes available upon request

Available versions

Available with Low Output Moving Coil phono section, or as line stage only.


Balanced Interconnects
Balanced phono cables
1 meter, DIN to XLR or RCA with ground post to XLR