recordinghacks


Large-Diaphragm Microphone Capsules

On this page you will find a catalog of all the large-diaphragm microphone capsules that are available for mods, repairs, or DIY microphone building.

Click the thumbnail photos to zoom in.

If you’re shopping, click the highlighted prices to purchase. (The links go either to the manufacturer, or to a reseller with the lowest prices for the capsule.)

Measurement note: the “ideal” capacitance value is provided by the manufacturer. The “actual” value was recorded by me, measuring the capacitance of each diaphragm to backplate, individually, then averaging the two.

Jump to:
K47 Capsules
K67 Capsules
CK12 Capsules
M7 Capsules
Miscellaneous Capsules

 

K47-Style Capsules

adk gk47

ADK GK47$400.00 / 400.00

Backplates: Single, 34.0mm diameter
Diaphragms: 27.3mm, 6.0-micron Mylar
Termination: Center
Capacitance: 78.0 pf ideal; 78.9 pF actual
adk gk47

The GK-47 is a recreation of the Neumann K47, built to modern tolerances. According to ADK, the capsule is “nearly a sonic clone” of the Neumann capsule, with the same polar pattern and frequency response, but higher sensitivity (due in part to its ability to run at higher voltage).

See also the GK-49, which offers an alternate voicing (based on the same capsule design).

Like all the 3-Zigma capsules, the GK-47 uses 99.999% pure gold to metallize the Mylar diaphragm. Further, the capsule is “pre-aged” by baking; this removes residual moisture and helps stabilize the capsules.

adk gk49

ADK GK49$400.00 / 400.00

Backplates: Single, 34.0mm diameter
Diaphragms: 27.5mm, 6.0-micron Mylar
Termination: Center
Capacitance: 74.0 pf ideal; 77.3 pF actual
adk gk49

The GK-49 is a subtle variation on the Neumann K47 design. Both are single-backplate capsules that reproduce the characteristic M7/K47 drilling pattern, and both use modern, high-tolerance manufacturing techniques to produce extremely consistent results. According to ADK, “The GK-49 aims to please the early U47 and M49 lovers who like more body and an even smoother top end. You can look at the GK-47 as a standard/modern issue K47 style capsule while the GK-49 is a more retro, late 40’s/early 50’s style capsule.”

Like all the 3-Zigma capsules, the GK-47 uses 99.999% pure gold to metallize the Mylar diaphragm. Further, the capsule is “pre-aged” by baking; this removes residual moisture and helps stabilize the capsules.

advanced audio ak47

Advanced Audio Microphones AK47$99.00 / 99.00

Backplates: Single, 32.0mm diameter
Diaphragms: 26.0mm, 6.0-micron Mylar
Termination: Center
Capacitance: 72.5 pF actual
advanced audio ak47

The AK47 is a 32mm version of the K47 capsule design. It is a true single-backplate capsule, with two center-terminated membranes.

The diaphragm is 6-micron Mylar, installed at the factory in China.

equinox q47d

Equinox Systems Q47D$199.00 / 199.00

Backplates: Single, 34.0mm diameter
Diaphragms: 26.5mm, 4.0-micron Mylar
Termination: Center
Capacitance: 81.8 pF actual
equinox q47d

The Equinox Systems Q47-D is a modern recreation of the Neumann K47, with historically-accurate backplate design. The 3-micron diaphragm is held down with brass tension rings.

Equinox Systems maintains stringent quality control standards, and can provide pairs of capsules matched to within 0.1dB average response (25–20,000 Hz). B-stock capsules are also available, at a discounted rate.

Each capsule includes a patent-pending, proprietary shockmount post/saddle, all necessary mounting screws, and an individual frequency-response chart.

Capsule components are sourced from Asia and the US; final assembly of capsule systems is done in the US.

Only a few hundred of these capsules were ever made; production was discontinued prior to 2014.

microphone parts rk47

Microphone Parts RK-47$119 / 149.00

Backplates: Single, 34.0mm diameter
Diaphragms: 26.5mm, 3.0-micron Mylar
Termination: Center
Capacitance: 90.7 pF actual
microphone parts rk47

The RK-47 is a modern recreation of the Neumann K47; it is a single-backplate capsule with characteristic K47 drilling pattern. The clamping rings in the early production runs were made of white plastic; beginning in 2014, the capsule was redesigned using brass clamping rings. The diaphragm material is 3-micron Mylar. Termination wires are Teflon-insulated oxygen-free copper.

Each RK-47 includes a 10.5mm mounting post, plus the necessary screws and termination wires to install the capsule. The company’s proprietary “supersaddle” is also included.

microphone parts rk7

Microphone Parts RK7$149.00 / 149.00

Backplates: Single, 32.1mm diameter
Diaphragms: 26.1mm, 6.0-micron Mylar
Termination: Center
Capacitance: 72.0 pf ideal; 72.0 pF actual
microphone parts rk7

The RK7 is a variation of the Neumann K47/Gefell M7 capsule design. It shares the single backplate and drilling pattern of the K47, the 32mm outside diameter of the M7, and the screwed-on clamping rings of the K47.

The diameter of the suspended portion of the diaphragm is approximately one-half millimeter smaller than on a 34mm capsule like the RK-47 or the Thiersch M7s. It is made of high-grade 6-micron Japanese Mylar, vapor-deposited with gold.

In 2013, the RK7 was upgraded to use US-made military-spec silver teflon wire. The saddle was also improved.

The capsule includes a 19.5mm mounting pedestal with saddle, termination wire, and all necessary screws.

The RK7 was discontinued in 2015.

peluso cek47

Peluso Microphone Lab CEK-47$236.00 / 236.00

Backplates: Dual, 35.0mm diameter
Diaphragms: 28.5mm, 6.0-micron Mylar
Termination: Center
Capacitance: 56.0 pf ideal; 49.3 pF actual
peluso cek47

The CEK-47 is a variation on the K67 design, although tuned with a lower resonant frequency to approximate the sound of the K47 capsule. It is not intended as an accurate reproduction of the K47, but rather is intended to offer a similar audio response.

Although some online reports state that the CEK-47 is the same capsule as the CEK-367, this is untrue. Both are dual-backplate designs with K67-style backplate drilling patterns, but the measured capacitance values are different, as are the resonant frequencies.

The CEK-47 uses imported metalwork; diaphragms of German Mylar are fitted and tuned in the US.

Note that the target capacitance of 56pF is measured at +65VDC. Our measurements are made at 0VDC.

peluso pk47

Peluso Microphone Lab P-K47$266.00 / 266.00

Backplates: Single, 34.1mm diameter
Diaphragms: 26.5mm, 6.0-micron Mylar
Termination: Center
Capacitance: 82.0 pf ideal; 75.4 pF actual
peluso pk47

The P-K47 is a historically-accurate recreation of the Neumann K47 capsule: a 34mm, single-backplate, center-terminated design with the K47’s characteristic concentric-rings drilling pattern.

Capsule backplates are manufactured in China at an aerospace-parts factory, to exacting specifications. Diaphragms made of German Mylar are sputtered in the US and installed and tuned in Virginia.

The target capacitance of 82pF is measured at +65VDC. Our “actual” capacitance measurement was taken at 0VDC.

 

K67-Style Capsules

adk gk67

ADK GK67$350.00 / 350.00

Backplates: Dual, 34.3mm diameter
Diaphragms: 27.4mm, 6.0-micron Mylar
Termination: Center
Capacitance: 72.0 pf ideal; 75.5 pF actual
adk gk67

Rather than cloning the Neumann K-67/K-87 capsule, which was designed for post-equalization in the amplifier circuit, the GK-67 aims to reproduce the sonic profile of the microphone with that EQ already built in. This allows the capsule to produce the sound typical of a U-67/U-87 while connected to a flat-response amplifier circuit — as ADK describes it, the “smooth top end and low-midrange body expected from a mint U67.”

For mic builders, this means the GK-67 is not the best choice for retrofitting into a U-67 or U-87A, unless the microphone’s built-in high-frequency EQ circuit is disabled. However, the GK-67 is a much better choice than a Neumann K-67 for anyone building a microphone without the negative-feedback circuitry of the U-67/U-87 platforms.

The GK-67, like most of the ADK capsules, has higher sensitivity (and better voltage handling ability) than its namesake. Like all the 3-Zigma capsules, the GK-67 uses 99.999% pure gold to metallize the Mylar diaphragm. Further, the capsule is “pre-aged” by baking; this removes residual moisture and helps stabilize the capsules.

advanced audio ak67

Advanced Audio Microphones AK67$75.00 / 75.00

Backplates: Dual, 35.1mm diameter
Diaphragms: 28.7mm, 6.0-micron Mylar
Termination: Center
Capacitance: 78.0 pf ideal; 70.2 pF actual
advanced audio ak67

According to Dave Thomas, the AK67 is based on the Neumann K67, but incorporates improvements engineered by Verner Ruvalds and John Peluso, resulting in a less-boosted high frequency response. It uses a 35mm backplate design, which is slightly larger than a Neumann K67 (34mm).

Like all K67-type capsules, it uses two backplates and center termination.

The AK67 uses diaphragms made of 6-micron Mylar, installed at the factory in China.

advanced audio ak89

Advanced Audio Microphones AK89$59.00 / 59.00

Backplates: Dual, 32.1mm diameter
Diaphragms: 26.0mm, 6.0-micron Mylar
Termination: Center
Capacitance: 66.0 pf ideal; 55.4 pF actual
advanced audio ak89

The AK89 is a 32mm copy of the Neumann K67. It is Advanced Audio’s version of the condenser capsule most commonly produced in China, and found in numerous imported condensers such as the Apex 460.

According to Dave Thomas, the capsule’s smaller diameter allows it to handle higher SPL than a larger capsule.

As of 2015, the AK89 is no longer offered for sale.

microphone parts k67le

Microphone Parts K67LE249.00

Backplates: Dual, 34.0mm diameter
Diaphragms: 27.1mm, 6.0-micron Mylar
Termination: Center
Capacitance: 57.0 pf ideal; 57.0 pF actual
microphone parts k67le

The K67LE is a premium K67 capsule manufactured at one of the oldest foundries in Europe. It is a dual-backplate, center-terminated design, made with historically accurate geometries and materials. The diaphragms are pre-aged 6-micron European Mylar, metallized with gold.

The capsule is tuned with a lower-amplitude high-frequency peak than most K67 designs, making it somewhat friendlier to linear circuit as it needs less corrective EQ.

It ships with a custom saddle, domed pedestal mount, screws and wires, and includes an individual frequency response chart.

microphone parts rk67

Microphone Parts RK-67$0.00 / 0.00

Backplates: Dual, 34.3mm diameter
Diaphragms: 27.5mm, 6.0-micron Mylar
Termination: Center
Capacitance: 61.0 pf ideal; 61.4 pF actual
microphone parts rk67

The RK-67 is a high-quality copy of the Neumann K67, selected to have the front and rear diaphragms match within 0.5dB for frequency response and sensitivity.

Each capsule includes a premium mounting post with all necessary screws to install the capsule.

The capsule was discontinued in 2014.

microphone parts rk87

Microphone Parts RK-87$119 / 149.00

Backplates: Dual (insulated), 34.1mm diameter
Diaphragms: 26.7mm, 6.0-micron Mylar
Termination: Center
Capacitance: 0.0 pF actual
microphone parts rk87

The RK-87 is K67-style capsule based on the Neumann K87.

The original K87 capsule was acoustically identical to the K67, but used a nonconductive shim between the two backplates, electrically isolating them. The capsule necessarily had 4 wires — one from each diaphragm, and one from each backplate. It was used in the original U87 (prior to the ‘A’ revision).

The RK-87 is a faithful copy of this K87 design, and is an ideal replacement for low-voltage multipattern circuits, such as the U87 (before the U87A revision).

Each RK-87 includes a 10.5mm mounting post, with saddle, termination wires (made of Teflon-insulated oxygen-free copper), and screws. These capsules also include the company’s “supersaddle” for additional mounting options.

peluso cek367

Peluso Microphone Lab CEK-367$225.00 / 225.00

Backplates: Dual, 35.0mm diameter
Diaphragms: 28.7mm, 6.0-micron Mylar
Termination: Center
Capacitance: 68.0 pf ideal; 71.6 pF actual
peluso cek367

The CEK-367 is a variation of the Neumann K67 capsule, tuned to have an extended high end and a less-pronounced presence peak at 8kHz than standard K67 capsules. This tuning is effected by creating a slightly smaller volume behind the diaphragm.

It is named for the Neumann M367, which like the M 269 was an AC701-based variant of the U67, built in very limited quantities for French broadcasting companies.

The capsule metalwork is manufactured at a Chinese aerospace-parts factory. Diaphragms are sputtered in the US and installed by Peluso in Virginia.

The target capacitance value of 68pF is measured at +65VDC; our measurements are made at 0VDC.

peluso cek89

Peluso Microphone Lab CEK-89$184.00 / 175.00

Backplates: Dual, 32.1mm diameter
Diaphragms: 25.9mm, 6.0-micron Mylar
Termination: Center
Capacitance: 50.0 pf ideal; 39.0 pF actual
peluso cek89

The CEK-89 is essentially a 32mm version of the Neumann K67 capsule. The smaller volume behind the diaphragm pushes the resonant frequency higher than is typical for a 34mm K67 capsule.

The capsule was designed for a specific low-cost microphone vendor, and has since been copied by most capsule factories in China. The 32mm K67 is the most common capsule found in imported condenser microphones.

According to John Peluso, the CEK-89 is a convenient drop-in replacement/upgrade for such microphones, due to its higher manufacturing tolerances and better diaphragm material, which provide a smoother, less-hyped high-frequency response than common 32mm Chinese-made capsules.

The CEK-89 is available in single- or dual-diaphragm versions; the two are identical, although the rear diaphragm on the “single” capsule has had its wire clipped off because that diaphragm did not meet Peluso’s performance specifications.

The target capacitance of 50pF is measured at +65VDC. Our measurement is made at 0VDC.

peluso pk67

Peluso Microphone Lab P-K67$266.00 / 255.00

Backplates: Dual, 34.0mm diameter
Diaphragms: 26.5mm, 6.0-micron Mylar
Termination: Center
Capacitance: 62.0 pf ideal; 52.7 pF actual
peluso pk67

The P-K67 is a dimensionally accurate copy of the Neumann K67, a dual-backplate, 34mm design. Because many original K67 capsules were drilled by hand, Peluso measured over 50 capsules to determine the specifications for this backplate.

Capsule metalwork is produced in China at an aerospace-parts factory. Diaphragms made of German Mylar are sputtered in the US and installed and tuned in Virginia. These capsules are tuned to match the original Neumann capsules, with resonant peaks at 8kHz and 10kHz.

The target capacitance of 62pF is measured at +65VDC. Our “actual” measurements are made at 0VDC.

studio projects b3

Studio Projects B3$0.00 / 100.00

Backplates: Dual, 34.1mm diameter
Diaphragms: 27.2mm, 3.0-micron Mylar
Termination: Center
Capacitance: 63.2 pF actual
studio projects b3

The B3 is a Chinese-made copy of the Neumann K67, with a 3-micron diaphragm.

studio projects c3

Studio Projects C3$0.00 / 100.00

Backplates: Dual, 34.1mm diameter
Diaphragms: 26.9mm, 6.0-micron Mylar
Termination: Center
Capacitance: 58.9 pF actual
studio projects c3

The C3 is a Chinese-made copy of the Neumann K67 capsule, with a 6-micron diaphragm.

studio projects cs5

Studio Projects CS5$0.00 / 130.00

Backplates: Dual, 34.1mm diameter
Diaphragms: 27.3mm, 6.0-micron Mylar
Termination: Center
Capacitance: 61.7 pF actual
studio projects cs5

The CS5 is a Chinese-made copy of the Neumann K67. These capsules are selected to meet a narrow range of sensitivity values, enabling any two CS5 microphones (or capsules) to be considered a matched pair.

studio projects lsm

Studio Projects LSM0.00

Backplates: Dual, 34.0mm diameter
Diaphragms: 26.6mm, 6.0-micron Mylar
Termination: Center
Capacitance: 28.2 pF actual
studio projects lsm

The LSM capsule, found in Studio Projects’ entry-level “Little Square Mic,” is a single-sided K67 copy manufactured in China. This is a Cardioid-only capsule, with a 6-micron Mylar diaphragm.

The rear side of the capsule has a clear Mylar diaphragm, as is typical for single-pattern K67-type capsules.

 

CK12-Style Capsules

adk gk12

ADK GK12$300.00 / 300.00

Backplates: Dual, 34.0mm diameter
Diaphragms: 27.4mm, 6.0-micron Mylar
Termination: Edge
Capacitance: 94.0 pf ideal; 97.4 pF actual
adk gk12

The GK-12 is not a physical clone of the AKG C12, but provides a very similar sonic response (both polar pattern and frequency) to a 1960’s C12 sound. According to ADK, the GK-12 retains the characteristic bright sound of 1960s-era CK12s, which had a more linear response than the earliest CK12 capsules.

See also the GK-251 for an alternate voicing.

Like all the ADK/3-Zigma capsules, the GK-12 is built with high-tolerance, modern machining techniques, and is capable of higher sensitivity and lower noise than the original namesake capsule. It uses 99.999% pure gold to metallize its Mylar diaphragm. The capsules are pre-aged by baking to drive off residual moisture.

adk gk251

ADK GK251$450.00 / 450.00

Backplates: Dual, 34.0mm diameter
Diaphragms: 27.7mm, 3.0-micron Mylar
Termination: Edge
Capacitance: 86.0 pf ideal; 89.9 pF actual
adk gk251

The GK-251 is a variation on the AKG CK12 design; like its sibling, the GK-12, it is not a physical clone of the AKG capsule, but provides a similar sonic response. It differs from the GK-12 in the use of a 3-micron (rather than 6-micron) Mylar diaphragm. The thinner material gives the capsule additional “air” on the top end, which ADK characterizes as evocative of the earliest, 1950s-era CK12s. This is a brighter, less linear sound than later CK12s (as emulated by the GK-12).

Like all the ADK/3-Zigma capsules, the GK-251 is built with high-tolerance, modern machining techniques, and is capable of higher sensitivity and lower noise than the original namesake capsule. It uses 99.999% pure gold to metallize its Mylar diaphragm. The capsules are pre-aged by baking to drive off residual moisture.

advanced audio ak12

Advanced Audio Microphones AK12$99.00 / 99.00

Backplates: Dual (insulated), 34.4mm diameter
Diaphragms: 27.8mm, 6.0-micron Mylar
Termination: Edge
Capacitance: 80.0 pf ideal; 83.5 pF actual
advanced audio ak12

The AK12 is a copy of the Peluso CEK-12. It is a dual-backplate capsule that substitutes K67-style backplates with a single inner chamber for the complex inner construction of the original AKG C12.

The diaphragm is 6-micron Mylar, installed at the factory in China.

microphone parts rk12

Microphone Parts RK-12$109 / 149.00

Backplates: Dual, 34.1mm diameter
Diaphragms: 26.5mm, 3.0-micron Mylar
Termination: Edge
Capacitance: 64.4 pF actual
microphone parts rk12

The RK-12 is a modern version of the brass AKG CK-12; it is made with custom backplates and a single interior resonant chamber. It is edge-terminated, with diaphragms are made of gold-plated 3-micron Mylar. The pre-installed termination wires are Teflon-insulated, oxygen-free copper.

Each capsule includes a 10.5mm mounting post with saddle and screws, and the company’s proprietary “supersaddle,” to afford more installation options.

peluso cek12

Peluso Microphone Lab CEK-12$257.00 / 245.00

Backplates: Dual (insulated), 34.2mm diameter
Diaphragms: 27.8mm, 6.0-micron Mylar
Termination: Edge
Capacitance: 78.0 pf ideal; 68.8 pF actual
peluso cek12

The CEK-12 is intended to reproduce the sonic profile of the AKG CK-12, with fewer parts and a less-complex internal construction. It was designed by John Peluso, based on work by former Neumann and Shure employee Verner Ruvalds.

The metalwork is produced at an aerospace factory in China. Backplates are tested in the US; those that meet tolerances are fitted with diaphragms at Peluso’s shop in Virginia. Diaphragm material is 6-micron German Mylar, sputtered in the US.

The “CEK” prefix stands for “Custom Engineering Capsule.”

The ideal 78pF capacitance value is measured at +65VDC; our measurements (69pF) were made at 0VDC.

 

M7-Style Capsules

cathedral pipes m7

Cathedral Pipes M7$0.00 / 0.00

Backplates: Single, 31.7mm diameter
Diaphragms: 26.5mm, 6.0-micron Mylar
Termination: Center
Capacitance: 81.7 pF actual
cathedral pipes m7

The Cathedral Pipes M7 is manufactured in California by Charles Dickinson. The backplates are machined from high-quality brass in the Los Angeles area; the diaphragm material (6-micron Dupont Mylar) is metallized with gold by a factory in the San Francisco Bay Area.

Dickinson tensions and glues the diaphragms by hand in his shop near Los Angeles.

The original design for this M7 was developed by Dale Ulan, but has since been refined, over many years’ research and testing, by Dickinson.

As of 2015, these capsules are no longer for sale to the DIY community.

thiersch blue

Thiersch Elektroakustik STW 7 Blue$358.00 / 358.00

Backplates: Single, 31.8mm diameter
Diaphragms: 26.9mm, PVC
Termination: Center
Capacitance: 77.5 pF actual
thiersch blue

The STW 7 is a historically-accurate reproduction of the Microtech Gefell M7. It is handbuilt in Germany by Thiersch Elektroakustik. The blue tape around the circumference indicates that the membrane material is PVC, as was true of the original M7 capsule.

PVC grows brittle as it ages, changing the timbre of the capsule. Nonetheless, it produces a unique sound, and is still used within some of the finest microphones made by Microtech Gefell.

The STW 7 is also available with additional holes drilled into the outside edge of the backplate, facilitating mounting to a capsule holder. This model is designated the STW 7.1.

The capsule ships bare; any of a variety of mounting post/saddle combinations can be purchased separately.

thiersch red

Thiersch Elektroakustik STW 7 Red$358.00 / 358.00

Backplates: Single, 31.8mm diameter
Diaphragms: 26.9mm, Mylar
Termination: Center
Capacitance: 79.9 pF actual
thiersch red

The STW 7 is a historically-accurate recreation of the Microtech-Gefell M7, built by hand in Germany by Thiersch Elektroakustik. The “red” version of the capsule uses a Mylar diaphragm; the “blue” STW7 is the PVC version of the capsule.

Whereas the diaphragms on most large capsule designs are held in place by screwed-on or snapped-on tensioning rings, the diaphragms on the M7 are glued into place.

Several versions of the M7 mounting system are available separately from Thiersch Elektroakustik.

 

Miscellaneous Capsules

shure rpm124

Shure RPM124100.00

Backplates: Single, 32.6mm diameter
Diaphragms: 21.8mm, 2.5-micron Mylar
Termination: Edge
Capacitance: 51.5 pf ideal; 28.0 pF actual
shure rpm124

The RPM124 is a single-sided, edge-terminated capsule with a Supercardioid polar pattern. It is used in the Beta 27.

It uses a single backplate, with an acoustic resistance network on the back side of the capsule. Its frequency response is flatter than Shure’s other large-diaphragm capsule designs.

The RPM124 is manufactured both in the US (Wheeling, IL) and Mexico (Agua Prieta).

The capsule uses Shure’s standard integrated plastic housing and mount.

shure rpm128

Shure RPM128150.00

Backplates: Single, 32.6mm diameter
Diaphragms: 21.9mm, 2.5-micron Mylar
Termination: Edge
Capacitance: 51.5 pf ideal; 26.2 pF actual
shure rpm128

The RPM128 is a large-diaphragm capsule, used in Shure’s KSM42. It is a dual-diaphragm, edge-terminated design; the rear diaphragm is clear Mylar, neither sputtered nor wired into the circuit.

The capsule was designed to reduce proximity effect, making it more forgiving for close-miked vocal applications.

The RPM128 is manufactured by hand at Shure’s facility in Wheeling, IL. Like all of Shure’s large-diaphragm capsules, it is built into Shure’s standard integrated housing/mount.

shure rpm131

Shure RPM131$0.00 / 296.00

Backplates: Dual, 32.8mm diameter
Diaphragms: 21.9mm, 2.5-micron Mylar
Termination: Edge
Capacitance: 60.5 pf ideal; 62.7 pF actual
shure rpm131

The RPM131 is a multipattern capsule used in Shure’s KSM44A (and KSM44). It is an edge-terminated design with diaphragms made of 2.5-micron Mylar.

Improvements to the production process yield exceptional consistency: less than 0.5dB variation in frequency response across recent production runs.

The RPM131 is manufactured by hand at Shure’s factory in Wheeling, IL. Like all the company’s large-diaphragm capsules, it is built into an integrated plastic housing and mount.

shure rpm140

Shure RPM140154.00

Backplates: Single, 32.6mm diameter
Diaphragms: 21.8mm, 2.5-micron Mylar
Termination: Edge
Capacitance: 51.5 pf ideal; 26.8 pF actual
shure rpm140

The RPM140 is an edge-terminated, large-diaphragm capsule. It is used in Shure’s SM27 and KSM27.

It is a single-backplate, single-diaphragm design. The membrane, as on all of Shure’s large-diaphragm capsules, is 2.5-micron Mylar.

The RPM140 is manufactured both in the US (Wheeling, IL) and Mexico (Agua Prieta).

The capsule uses Shure’s standard integrated housing and mount.