As the thirtieth anniversary of the Sony MDR-CD900 and MDR-V6 headphones is upon us, I thought I'd take an opportunity to pay a little homage to the ubiquitous headphones. But before I begin: Sony, Walkman, etc., are all trademarks of Sony Corporation. Sony had nothing to do with this site; all of the photos except for one are mine from my own collection; the text is mine culled from various sources, including other websites, catalogues, and service manuals, so the text and history is Copyright (C) 2016, Kai Harada.

 

And if Koji Nageno reads this page, please contact me; I have some questions...

 

 

HISTORY

 

In the early 1980s, with the advent of the Walkman, Sony pioneered lightweight headphones, allowing users to take quality sound reproduction with them. Most of these headphones (MDR-1, MDR-2, MDR-3, MDR-4, and MDR-5) featured 23mm dome drivers, but higher-end models, such as the MDR-7, used 28mm drivers.  The MDR-4L1S, included with the WM-2 Walkman, became somewhat of a status symbol with their orange earpads.

 

 

MDR-4T HEADPHONES, WITH LONGER CABLE, BLACK HOUSING,

UNIMATCH PLUG, AND NO MUTE SWITCH. ORIGINAL EARPADS WERE BLACK.

 

 

 

MDR-4L1S HEADPHONES, WHICH CAME WITH THE WM-2.

ORIGINAL EARPADS WERE ORANGE.

 

 

 

MDR-5a, MDR-7.

 

 

 

Audio professionals, however, opted for the circumaural (on the ear) DR-series headphones, especially in ENG (Electronic News Gathering) applications.  Originally introduced in the 1970s, the early DR generation sported cone (paper) drivers, but as fidelity became increasingly more important, Sony experimented with other materials, resulting in a dome driver that carried into their lightweight models in the 1980s.

 

The DR-6M, DR-M7, and DR-Z6 models became especially popular because of their ability to be folded for easy carrying. Many Japanese reporters used these models along with early Sony cassette tape recorders, called "Densuke" in Japan, based on a cartoon-character report of the same name and generation.

 

 

DR-Z6 IN ORIGINAL PACKAGING

 

DR-M7

 

DR-6M

 

In 1983, Sony and Phillips introduced the Compact Disc, and with it came a slew of digital recording equipment. Sony engineers realized the need for a higher-quality headphone suitable to reproduce the ful frequency range of the new format. Coinciding with the Compact Disc, Sony released the MDR-CD5 and MDR-CD7 models, both utilizing a 30mm dome driver, specifically designed for digital audio applications. The two models were similar, but the CD7 boasted a gold diaphragm and was a sleek black color, while the CD5 was silver colored and had a standard PET diaphragm. They were extremely lightweight and provided some limited isolation from outside noise with an oval on-the-ear earpad design. The connecting cord terminated at the left ear only, and made them very popular in professional audio applications.

 

 

MDR-CD5; EARPADS HAVE WORN AND REVEALED ORANGE FOAM, BUT

ORIGINALLY THEY WERE BLACK WITH A URETHANE COVER.

 

 

                                                                                                 THE FIRST GENERATION

 

Finally, in late 1985, Sony released the MDR-CD900 in Japan, and the MDR-V6 in the rest of the world, finally bridging the gap between high quality audio and a closed-ear design. These were flagship "DIGITAL MONITOR" headphones with full 20Hz-20kHz (some specifications state 5Hz-30kHz), a closed ("supra-aural") over-the-ear oval design, and could be folded up for portability. They boasted a CCAW voice coil, samarium cobalt magnets, a single-sided coiled cord, and a 40mm diaphragm. The Japan-only MDR-CD900 featured an Amorphous Diamond diaphragm, whereas the Export-Only MDR-V6 had a standard PET diaphragm. All headphones of this series were rated at 63ohm impedance at 1kHz.

 

 

 

THE WHOLE FAMILY:
MDR-CD700, MDR-CD900, MDR-V6, MDR-V7, MDR-7506, MDR-CD900ST

 

 

 

MDR-CD900 - NOTE "DIGITAL MONITOR" AND SHINY SURFACE

 

 

 

MDR-CD900, ORIGINAL

 

 

 

MDR-CD900, FOLDED

 

 

MDR-CD900 ORIGINAL TAG

 

 

 

MDR-CD900, CLOSEUP

 

 

MDR-V6, FOLDED; NOTE "STUDIO MONITOR" AND MATTE SURFACES.

 

MDR-V6, UNFOLDED (PARDON THE DUST BY THE HANGER)

 

 

In 1986, the other members of the family appeared: the MDR-CD700 (Japan) and MDR-V7 (rest of the world) seemed to be designed for at-home "hi-fi" listening, with a non-foldable design and a long, straight cord. The CD700 utilized a 40mm Gold diaphragm, while the V7 used a 40mm titanium diaphragm. (Some sources say that the MDR-V7 had a 50mm diaphragm but this is incorrect). Non-foldable designs had a shorter headband compared to the foldable versions.

 

        

MDR-CD700 (JAPAN ONLY)                                                                    MDR-V7, NOTE CABLE PASSING THROUGH HANGERS

 

 

MDR-CD700 (LEFT), MDR-CD900 (RIGHT)

(NOTE DIFFERENCE IN HEADBAND STYLE)

 

 

 

MDR-V7 IN ORIGINAL PACKAGE (EU VERSION)

 

(30mm-driver "on-the-ear" versions also appeared, namely the MDR-V5, V4, V3, V2, V1, V606, V404, CD500, CD300, and CD100; someday I may write something about those).

 

Although the MDR-V6 was designed for consumer applications, professional sound engineers quickly discovered their utility, and in 1991, Sony released the MDR-7506, which was essentially an MDR-V6 with a gold-plated plug and neodymium magnets in their drivers; they were distributed through Sony's Professional Equipment division and thus came with a better warranty. A Service Manual, listing all repair parts, was also included for easy in-the-field repair.

 

(Contrary to some reports, the wiring for the MDR-V6 and MDR-7506 is EXACTLY THE SAME as all the other Sony headphones in this family).

 

MDR-7506

 

 

MDR-7506, ALSO "STUDIO MONITOR"

 

Back in Japan, Sony worked with its recording studios-- CBS/Sony Shinanomachi Studios-- later Sony Music Studios-- to produce a headphone specifically designed for professional use. Using MDR-CD700 and MDR-CD900 consumer headphones as a base model, sound engineers gave notes to Sony engineers to devise a particular model voiced for studio monitoring applications.

 

These early models were confusingly named: first, modified MDR-CD900 headphones were given a new sticker, and called MDR-CD900/CBS, but they retained the shiny finish of the consumer versions:

 

 

MDR-CD900/CBS, WITH CBS/SONY LABEL (PHOTO FROM A YAHOO! JAPAN AUCTION PAGE; THESE SOLD FOR ABOUT $400 IN 2015).

 

A second series of professional studio-only headphones with design concepts from the CD700 and V7 appeared in late 1989; these were only available through "official" channels. These headphones, also labelled MDR-CD900, were no longer foldable, had a matte finish, and integrated the left-to-right cable pass into the ear hangers. The cable was no longer coiled, and terminated in a 1/4" plug; no Unimatch 1/8" connector with 1/4" adaptor like the original CD900, V6, or 7506.

 

 

MDR-CD900 STUDIO VERSION WITHOUT THE "ST" NAME (1989-1995 VINTAGE)

 

After 1995, the housings were changed to officially name the headphones MDR-CD900ST (STudio, of course), and were available to the public in Japan, packaged in a plain white box (now cardboard colored), with no manual and no warranty. Like the MDR-7506 internationally, the MDR-CD900ST headphones are designed to be easily reparable, and spare parts abound for the professional in Japan. Some special limited-edition variants for promotional use have also been released, as listed below.

 

 

  

RECENT MDR-CD900ST ON LEFT, ORIGINAL MDR-CD900 ON RIGHT

 

MDR-CD900 VARIANTS:

 

Original (consumer) MDR-CD900 (late 1985):

            foldable, long headband with "DIGITAL MONITOR" in gold.

            single sided coiled cord terminating in a 3.5mm gold connector with Unimatch adaptor

            left/right decals were gold

            cable from left to right routed on outside of hanger

            all housings were beautifully shiny

            register front made from a thinner paper

 

MDR-CD900CBS (circa 1988):

            not foldable, shorter headband, like the CD700 and MDR-V7; "STUDIO MONITOR" in gold, like the MDR-V7.

            single-sided 2.0m straight cord terminating in a 1/4" plug,

            later models had matte finish like most of the other in the series,

            labeled as MDR-CD900, some with decal that said "CBS SONY GROUP,"

            left/right decals were red/blue, like the V6,

            driver modified to meet CBS/Sony standards,

            driver register paper different from all others,

            "micron silk" (fiberglass acoustic batting) added behind driver to reduce resonance of cup,

            cable from left to right carried within the ear hanger, preventing accidental crimping and breakage of that cable between the yoke and the ear cup, like the V7.

 

MDR-CD900ST (evolved from CD900CBS around 1989):

            all as the 900CBS, except labeled as MDR-CD900ST,

            cable lengthened to 2.5m, but still straight, terminating in 1/4" plug.

            available for public purchase around 1995.

 

MDR-CD900ST/WR WIRE MODEL:

            a limited edition variant with white housings, and a coiled cord terminating in a 3.5mm Unimatch gold-plated plug, like used on the MDR-7506

 

MDR-CD900ST/OT MODEL:

a limited edition variant with orange housings, and a straight cord terminating a 3.5mm Unimatch gold-plated plug, liked used on the CD700.

 

MDR-CD900ST/LOOPA MODEL:

            a limited edition variant with red housings.

 

 

 

MDR-CD900ST/WR

 

 

                                                                                     40mm first-generation Sony Headphone Comparison Chart:

 

 

 

MODEL / 名前

MDR-CD900 (orig)

MDR-V6

MDR-CD700

MDR-V7

MDR-CD900CBS

MDR-7506

MDR-CD900ST

PRODUCTION / 発売

end 1985 - 1992

end 1985 - present

Oct 1986 - 1989

1987 - ?1992?

1988 - 1995

1991 - present

1989, 1995 - present

MARKET / 市場

JPN ONLY

US, EU, PAC

JPN ONLY

EU, US

JPN ONLY

US, EU, PAC

JPN ONLY

MANUFACTURE / 国系

JPN

JPN/CN/THAI

JPN

JPN

JPN

JPN/CN/THAI

JPN

DRIVER / ドライバーの直径

40mm

40mm

40mm

40mm

40mm

40mm

40mm

VOICE COIL / ボイスコイル

CCAW

CCAW

CCAW

CCAW

CCAW

CCAW

CCAW

MATERIAL / ダヤフラーム

Amorphous Diamond

Mylar/PET

Amorphous Gold

Amorphous Titanium

Mylar/PET

Mylar/PET

Mylar/PET

MAGNET / マグネット

Samarium Cobalt

Samarium Cobalt

?Samarium Cobalt?

?Samarium Cobalt?

Neodymium

Neodymium/Sam Cobalt

Neodymium

IMP / インペーダンス

63

63

63

63

63

63

63

DRIVER ORIG # / ドライバー(旧)

1-505-076-21

1-505-076-11

1-505-076-31

1-505-076-01, 41

1-505-093-11

1-505-076-11

1-505-093-11

DRIVER CURR # / ドライバー(新)

N/A

1-542-491-11, 31

N/A

N/A

N/A

1-542-491-11, 31

1-542-492-21, -31

DRIVER CODE / ドライバーコード

040F002 (we think)

040F001; 040F001P

040F003

040F004

040F005

040F001; 040F001P

040F005; 040F005Q

in 2007; now 040F001Q

in 2002; now 040F001Q

FOLDABLE / 折りたたみ?

YES

YES

NO

NO

NO

YES

NO

HEADBAND LENGTH / ヘッドバンドの長さ

LONG

LONG

SHORT

SHORT

SHORT

LONG

SHORT

HEADBAND TEXT / ヘッドバンドの語句

"DIGITAL MONITOR"

"STUDIO MONITOR"

"DIGITAL MONITOR"

"STUDIO MONITOR"

"STUDIO MONITOR"

"STUDIO MONITOR"

"STUDIO MONITOR"

TEXT COLOR / ヘッドバンドの語句の色

GOLD

SILVER

GOLD

GOLD

GOLD

SILVER

GOLD

L/R LOGO / 「左」「右」ロゴの色

Gold/Gold

Blue/Red

Black/Black

Gold/Gold

Blue/Red

Blue/Red

Blue/Red

STICKER / カップスティッカ

"for DIGITAL"

"for DIGITAL"

"for DIGITAL"

"for DIGITAL"

"for DIGITAL"

"Professional"

"for DIGITAL"

CABLE PATH / ケーブルの通路

CUP

CUP

CUP

HANGER

HANGER

CUP

HANGER

PARTS SHEEN / 光沢

SHINY

MATTE

MATTE

MATTE

SHINY -> MATTE

MATTE

MATTE

SOUNDHOLE / サウンドホール

RECTANGLE (F only)

RECTANGLE (F only)

RECTANGLE (F only)

CIRCLE (Sm on R, Sm on F)

CIRCLE (Lg on R, Sm on F)

RECTANGLE (F only)

OVAL (R only)

POUCH / ポーチ付き?

Yes

Yes

No

No

No

Yes

No

CABLE / ケーブル

Coiled Brown

Coiled Black

Straight Black, 3m

Straight Black, 3m

Straight Black, 2m

Coiled Black

Straight Black, 2.5m

PLUG / プラグ

Unimatch

Unimatch

Unimatch

Unimatch

1/4"

Unimatch

1/4"

METAL / プラグのメッキ

Gold

Nickel

Gold

Gold

Nickel

Black

Nickel

EARPAD / イヤーパッド

2-115-668-03

2-115-668-03

2-115-668-03

2-115-668-03

2-115-695-01

2-115-668-03

2-115-695-01

HANGER LID, L / ハンガ蓋、左

2-113-130-01

2-113-130-11

2-113-130-11

2-115-669-01

2-115-669-01

2-113-130-11

2-115-669-01

HANGER LID, R / ハンガ蓋、右

2-113-131-01

2-113-131-11

2-113-131-11

2-115-670-01

2-115-670-01

2-113-131-11

2-115-670-01

EAR HANGER, L / イヤーハンガー、左

2-113-132-01

2-113-132-11

2-113-132-11

2-115-671-01

2-115-671-01

2-113-132-11

2-115-671-01

EAR HANGER, R / イヤーハンガー、右

2-113-133-01

2-113-133-11

2-113-133-11

2-115-672-01

2-115-672-01

2-113-133-11

2-115-672-01

 

 

 

       

MDR-CD700 GOLD DIAPHRAGM                                                     MDR-CD900 (ORIGINAL) DIAPHRAGM                                                MDR-V7 TITANIUM DIAPHRAGM

 

 

 

   

MDR-7506 DIAPHRAGM                                           MDR-CD900ST DIAPHRAGM (NOTE DIFFERENT PAPER ON BAFFLE)

 

 

MDR-CD900ST WITH MICRON SILK DAMPER IN CUP
(ONLY MODEL WITH THIS ABSORPTION).

 

 

 

Many, many parts from the different series of this generation are interchangeable, leading to a lot of customization possibilities, which I may discuss at some other point.

 

 

 

                                                                                               THE NEXT GENERATIONS

 

After the original V-series was introduced worldwide, Sony introduced several generational improvements over the years, but only the V6/7506/CD900ST have remained in steady production for thirty years.

 

            SECOND GENERATION:            MDR-CD555/666, MDR-CD777/888, MDR-CD999  (~1988)

                        -CD555/666 utilized 30mm drivers with a titanium diaphragm in a newer form factor.

                        -CD777/888 utilized 40mm drivers with a sapphire-evaporated diaphragm in this same newer form factor.

                        -CD999 utilized 50mm drivers with a amorphous diamond diaphragm.

 

            THIRD GENERATION:                MDR-CD250, MDR-CD350, MDR-CD450, MDR-CD550, MDR-CD750, MDR-CD850, MDR-CD950, MDR-CD1000, MDR-CD3000 (~1991), MDR-R10 (1988)

                        -CD250, 350, and 450 utilized 30mm drivers, and differed only in form factor.

                        -CD550 and 750 utilized 40mm drivers.

                        -CD850, 950, and 1000 utilized 50mm drivers; CD950 used amorphous diamond diaphragms, and CD1000 used biocellulose diaphragms.

                        -CD3000 was a flagship model utilizing 50mm drivers with biocellulose diaphragms and a non-resonant housing.

                        -MDR-R10 was THE king of headphones, utilizing 50mm drivers with biocellulose diaphragms, housing from Zelkova wood, and lambskin pads. Only 3000 were made!

 

            THIRD GENERATION "STUDIO MONITOR" SERIES:                  MDR-V600/Z600 (1992), MDR-V900/Z900 (1992)

                        -V600 or Z600 were designed to be direct successors to the V6, addressing some users' complaints that the V6 sound signature was "too bright." A lower-impedance 40mm driver was used.

                        -V900 or Z900 were 50mm versions, and evolved into the V900HD and Z900HD versions with extended high frequency range.

 

            FOURTH GENERATION:            MDR-CD270, MDR-CD370, MDR-CD470, MDR-CD570 (~1994), MDR-CD770 (1996), MDR-CD1700 (1996)

                        -CD270, 370, and 470 utilized 40mm drivers in a new form factor that was designed to reduce mechanical noise when the headphones were moved (which was an issue with the third generation).

                        -CD570 and CD770 utilized 50mm drivers in this same new form factor.

                        -CD1700 utilized 50mm drivers with Vectran biocellulose diaphragms.

 

            FIFTH GENERATION:                 MDR-CD280, MDR-CD380, MDR-CD480, MDR-CD580, MDR-CD780, MDR-CD2000 (2000)

                        -CD280 utilized 30mm drivers in a newer form factor with softer, bigger earpads.

                        -CD380, 480, and 580 utilized 40mm drivers in this same new form factor; 480 and 580 had a detachable cord.

                        -CD780 utilized 50mm drivers, also with detachable cord.

                        -CD2000 utilized 50mm drivers with Vectran biocellulose diaphragms, also with detachable cord.

 

            FIFTH GENERATION "DJ" SERIES:                 MDR-V500DJ/Z500DJ (1999), MDR-V700DJ/Z700DJ (1999)

                        -V500DJ or Z500DJ used 40mm drivers and had fully swivelling earcups, making them popular with DJs.

                        -V700DJ or Z700DJ used 50mm drivers and had fully swivelling earcups, making them popular with DJs.

 

 

 

 

REFERENCES, SOURCES, AND LINKS

 

Sony Music Entertainment's official page on the MDR-CD900ST; Japanese only:

http://www.smci.jp/mob/pageShw.php?site=headp&cd=cd900st

 

A pretty comprehensive list of Sony headphones through the early 2000s is available here; it's in Japanese:

http://20cheaddatebase.web.fc2.com/SONY/sonyindex.html

 

This person's blog in Japan details many modifications and repair procedures for the MDR-CD900ST, which are often applicable to other models; great photos:

http://blogs.yahoo.co.jp/linear_pcm0153/MYBLOG/yblog.html?fid=0&m=lc&sk=0&sv=cd900

 

A bit more history of the CD900ST is here; it's in Japanese:

http://kkkk3150.blog54.fc2.com/blog-entry-25.html

 

Makeup Company services and supports the MDR-CD900ST in Japan:

http://www.cd900st.com/

 

Cartonode Engineering makes special modifications to the MDR-CD900ST; Japan/Japanese only:

http://www.cartonode.com/

 

His blog is here, detailing modifications to the MDR-CD900ST:

http://ceproducts.exblog.jp/i2/

 

Umbrella Company services and supports the MDR-CD900ST in Japan and also makes a balanced headphone amplifier; Japanese only:

http://umbrella-company.jp/buzz/Sony-mdr-cd900st_mod.html

 

This guy just took some nice photos of his MDR-CD900ST; Japanese only:

http://akihikomatsumoto.com/blog/?p=456

 

COMING SOON (OR EVENTUALLY)

 

Fake MDR-7506s from China, and how to identify them.

 

Service Manual collection.

 

Catalogue scans.

 

Modifications to any of the series.