Guts | Manley Labs Manley Massive Passive Stereo Tube Equalizer

THE GUTS

AC VOLT CHANGE

GAIN TRIM			GAIN TRIM
+4 / -10 CHANGE			+4 / -10 CHANGE
5751/12AX7			5751/12AX7
6414/12BH7	6414/12BH7	6414/12BH7	6414/12BH7

1)To Open: Disconnect the AC Power cable, let sit 15 minutes to allow the power supply capacitors to discharge. Remember there are high voltages (300VDC) used in the Massive Passive and that the capacitors may continue to hold a charge after power is removed - BE CAREFUL! We suggest using gloves and/or "one hand only" when the top is off.

Remove the single Philips Machine screw located on the top perforated panel (towards the back and center). Slide the perforated panel towards the back.

2)Replacing Tubes: The tubes are marked as to their type 5751/12AX7 (for voltage gain) and 6414/12BH7 (for line drivers). Another warning: Tubes get HOT. Let them cool before you attempt to touch them. Wiggle the tube back and forth as you pull it up. If you suspect a tube, you can swap it with the other channel. If the problem follows the tube, you were right, it is that tube. If not, try swapping another pair of tubes. It is a good idea to have a few spare tubes for emergencies as this will fix better than 90% of most problems.

3)Changing AC MAINS VOLTAGE: Disconnect the AC Power cable. See on the diagram above the "AC VOLT CHANGE". Use a small flat screwdriver set voltage change over switch to 120VAC or 240VAC operation. Replace main Fuse with correct type and value. For fuse information refer to Pg. 29..

4)Changing the 1/4" phone jacks for -10dBv levels: The Massive Passive is factory wired for professional +4dBu levels for both all of the XLR and 1/4" phone jacks. This procedure only changes the 1/4" jacks - not the XLRs. Do not assume that "balanced" implies +4dBu levels or that "unbalanced" implies -10dBv consumer levels. Balanced only means that there are 3 wires in the cable and that 2 of these wires carry signal in opposite phases and that the same impedances (source especially) exist. Unbalanced refers to a cable system with two wires (signal and ground). "+4dBu" refers to professional signal levels (0VU=1.228 volts AC into 600 ohms). "-10dBv" refers to consumer signal levels common to hi-fi and low budget semi-pro gear and is typically 14 db lower than pro levels. The common connector is the RCA style phono jack. 1/4" jacks are used for a wide variety of signal types and levels, including +4, -10, instrument Hi-Z and speakers and headphones. 3 conductor plugs are used for balanced signals, inserts (send and return) and stereo (L&R) which tend to be incompatible. Simply plugging in a 1/4" to 1/4" cable from one piece of gear to the next is not guaranteed to work. You may have to check the operators manuals if you run into problems.

See the diagram above for the DIP SWITCH locations and the next page for a closer look.

Manley Massive Passive Stereo Tube Equalizer specifications

The Manley Massive Passive Stereo Tube Equalizer stands as a hallmark in the world of high-end audio processing, renowned for its unique design and exceptional sound character. This equalizer embodies the brand's commitment to quality and sonic integrity, making it a coveted piece of equipment for professional audio engineers and enthusiasts alike.

One of the standout features of the Massive Passive is its all-tube signal path. Utilizing vacuum tubes, the equalizer imparts a warm, rich tone that is often described as “musical”. This tube-based design works in conjunction with a passive equalization topology, which means that rather than boosting frequencies through active components, it relies on a network of inductors and capacitors, preserving the audio signal's purity while allowing for versatile tone shaping.

The Massive Passive is equipped with a wide range of frequency bands, allowing engineers to tailor their sound precisely. It features a dual-channel configuration with controls for both left and right channels, enabling stereo adjustments that maintain phase coherence. Each channel includes numerous frequency selections across both low and high ranges, granting access to numerous filtering options that highlight or attenuate specific frequencies as required.

An essential aspect of the Massive Passive is its innovative design, characterized by high-quality components, including Manley’s custom-designed transformers and circuit boards. These components are engineered to minimize noise and distortion, ensuring that the equalization process does not compromise the integrity of the source material. Users can enjoy the convenience of both low-frequency and high-frequency adjustments, as well as the ability to boost or cut with a substantial range, from a subtle touch to significant alterations.

One of the intelligent aspects of the Massive Passive is its 'bypass' feature. This allows users to seamlessly compare the processed sound against the original audio, making it easier to make informed decisions on adjustments. The build quality of the unit is also remarkable, showcasing a robust chassis that is both aesthetically pleasing and incredibly durable, signifying Manley Labs’ attention to detail.

Ultimately, the Manley Massive Passive Stereo Tube Equalizer encapsulates the essence of analog warmth and precision in audio processing. By integrating sophisticated engineering with user-friendly controls, it provides both professional and home studios with the tools necessary to achieve that sought-after sonic richness, making it a top choice among discerning audio professionals.