The U87 presents a wide range of features and versatility that make it one of the most desirable mics available. Users are recognising the microphone immediately by its distinctive design. Well-known for its warm and well balanced characteristics, it's your perfect choice as a vocal microphone for all types of music and speech. Most commonly used as the main microphone for orchestra recordings or as spot mic for single instruments it is the ideal general-purpose microphone - in studios, for broadcasting, film and television.
The U87 is equipped with a large dual-diaphragm capsule with three directional patterns: omnidirectional, cardioid and figure-8. These are selectable with a switch below the headgrille. A 10dB pre-attenuation switch is located on the rear; it enables the microphone to handle almost any sound thrown at it. Furthermore, the low frequency response can be reduced to compensate for proximity effect.
Released in 1967 the U87(i) was built as a successor to the U67; changing the tube setup to FET. Housing and electronic components were kept the same, as was the case for the U77.
The U87(i) capsule, K87, had a dual backplate, dual diaphargm 34mm capsule and a spacer isolating each side. The backplates were made of brass while the diaphargm was made of gold sputtered mylar. Four wires were used as the two backplates of the capsule were electrically insulated from each other. This allowed each electrode to be in opposite phase, making figure-8 possible. The capsule used 48V for polarisation when run on 48V phantom power and 46V when powered by 2x22.5V internal batteries.
The U87(i) circuit board was populated with a battery compartment on the front and FET/Transformer setup on the rear. The battery compartment took 2 x22.5V batteries, and the switch below had to be set to INT (internal power supply) to use batteries. With phantom power, the switch would need to have been in EXT (external supply mode).
The U87(i) comprised of three bead blasted housing components; headgrille, tube and endcap. Three mesh sheets gave the headgrille it's robust classic look. The tube had a slit on the rear side (a window to view the battery meter level) and a purple Neumann badge, used exclusively on the fet80 series discreet solid state mics.
The U87(i) came with two types of connectors, an XLR 3 pin and a 7 pin large Tuchel connector. The model name indicates the connector in use:
U87 - Tuchel
U87i - XLR
The 'i' in U87i, refers to the 'i'nternational XLR connector. The Tuchel version: U87, was made as broadcasting companies required these. Both versions, U87 and U87i required 48V phantom power.
Production came to an end in 1986 and the second generation followed later that year. The U87Ai had arrived.
Released in 1986, U87Ai is the second generation U87(i). The U87Ai is identical to its older brother with the only significant change being the introduction of a DC-DC convertor, and the subtraction of a battery compartment.
The capsule reverted back to that found in a U67. Capsule K67 now called K870/K67 is acoustically the same as U87(i)'s K87. The only difference in the two is the two halves of the backplate of the K870/K67 are not electrically insulated from each other. The K870/K67 has a 40-micron spacer made of aluminium where as the K87's spacer is made of plastic (non-conductive) - leading to the typical three connections of a dual-diaphragm design.
As batteries became difficult to find and the battery compartment became redundant, Neumann decided to introduce a DC-DC converter like that of a U77, which would deliver 60V to the capsule. The U87Ai borrowed the DC-DC converter from U89, which had been in use since 1980. However, the amplifier circuits themselves are different in the two mics. This circuit increases the phantom power's available 48VDC to 60VDC, and thereby polarizes the capsule voltage with 12 more volts than in the U87(i). The increase in voltage improves the microphone's Signal to Noise ratio by 3dB, and overall output by 10dB.
Although very similar in physical appearance, a few small changes have been made to the U87Ai. The tube housing no longer has a slit on the rear, as there is no battery meter level to be read. The housing parts have a coarser shine of bead blasting as opposed to the fine matte finish seen on the U87(i).