Chet Atkins was Gretsch's first big endorser, and his name sold the 6120 from the mid-1950s. He also hated the hum of its pickups. Those pickups were DeArmond single coils, and the humbucker Ray Butts built to fix them became the Filter'Tron, the heart of what fans call the Great Gretsch Sound. The pickup on a Gretsch tells you roughly when it was made, or which era a modern one copies. Here's how to tell them apart in listing photos.
The DeArmond Dynasonic
DeArmond pickups came from Rowe Industries in Toledo, Ohio, where Harry DeArmond designed pickups for owner Bud Rowe. Rowe's Model 2000 is the one Gretsch put on its better electrics and called the Dynasonic. Gretsch later renamed it the Fidelatone so it wouldn't clash with Rogers drums' Dyna-Sonic snare. You can spot one by its black face with two rows of metal, the pole pieces in one row and the screws that set their height in the other. That double row makes people mistake it for a humbucker, but it's a single coil, and the steel parts of the height mechanism are part of its sound.
In the mid-1950s you'll find two Dynasonics on the 6120, the Duo Jet and its Silver Jet and Jet Firebird siblings, the 6121 Chet Atkins solid body, the Roundup and the White Falcon. Gretsch's Cliff Gallup signature Duo Jet is built as a copy of Gallup's own guitar, a 1954-style Duo Jet that he kept stock.
Ray Butts and the Filter'Tron
Butts was an amp builder from Cairo, Illinois, and a friend of Atkins. He wired two coils in series and out of phase so each cancels the other's hum, and he showed Atkins a working pickup in Nashville in 1954. Atkins put a prototype set in the red 6120 that appears on the cover of his 1956 album Finger-Style Guitar. Gretsch wrote to Butts in December 1955, agreed to make the pickup in-house and pay him royalties, and worked up the production version with Gretsch's Jimmie Webster. The name comes from filtering out electronic hum.
Gretsch showed the pickup at the 1957 NAMM show, the same show where Gibson showed Seth Lover's PAF. Letters in Butts's papers show Gibson president Ted McCarty told him in 1956 to stop or take a license, and Butts replied that Gibson might be the infringer. The companies eventually agreed the two men had invented their pickups independently. Butts got his patent on June 30, 1959, a month before Lover, although Lover had filed first. Our guide to PAF-era Les Pauls covers Gibson's side.
A Filter'Tron isn't a Gretsch-badged PAF. Its bobbins are smaller than Gibson's, which puts the two rows of pole screws closer together, and its alnico bar magnets are twice as thick. Output is low, typically 4,000 to 5,000 ohms. Guitar World calls the sound warm and round but edgy, and Guitar.com places it between the two big names, with less power than a Gibson humbucker or P-90 and less brightness than a Fender single coil.
When each one was used
Gretsch began fitting Filter'Trons in 1957 and over the following years used them in almost every model. In Guitar HQ's model notes, 1958 is the changeover year for the 6120, Duo Jet, 6121 and White Falcon. That's also the year neoclassic thumbprint inlays replaced the humptop markers, so humptops on a fingerboard generally mean 1957 or early 1958 and a likely Dynasonic guitar.
Some models never had Dynasonics. The Country Gentleman arrived in late 1957 with Filter'Trons from the start, and it's the guitar George Harrison played on the Beatles' first Ed Sullivan Show appearance. The Tennessean launched in 1958 with one Filter'Tron at the bridge, and the Anniversary launched the same year with Filter'Trons too. Both later moved to the HiLo'Tron, a single coil with its poles through a black face that Guitar HQ calls a single-coil version of the Filter'Tron. The Anniversary switched in 1960, and the Tennessean went to two HiLo'Trons in 1961. From 1964 Gretsch also used the Super'Tron, which has two metal blades in place of pole screws, and the Country Gentleman got one Super'Tron and one Filter'Tron that year.
Reading a Filter'Tron cover
Filter'Tron covers help date a guitar. Gretsch kept using covers pre-stamped PAT. APPLIED FOR until it ran out of them in 1960, well after the patent was granted. Guitar HQ's summary runs like this.
- 1957 to 1958. No markings on the cover and a smooth plastic frame.
- 1958 to 1960. PAT. APPLIED FOR stamped on the cover and a smooth frame.
- 1960 to 1970. Patent number 2892371 on the cover and a ridged plastic frame.
- 1970 to 1981. A black face with no cover markings, height-adjustable, in an open metal frame.
After Baldwin, and the reissues
Baldwin bought Gretsch in 1967 and moved production from Brooklyn to Arkansas in 1969. Under Baldwin the Filter'Tron was changed several times, with ceramic magnets and new poles and covers, before being replaced, and the old company stopped making guitars in the early 1980s. Fred W. Gretsch restarted production in 1989, with the Professional series built at Terada in Japan, and since Fender took over production and marketing in the early 2000s the Filter'Tron has been back to its original specs. TV Jones made his name with vintage-accurate Filter'Tron-style pickups in those years, and Gretsch fits TV Jones pickups to some current models, such as the Brian Setzer Hot Rod 6120.
Modern Gretsches come both ways. The Duo Jet line includes Dynasonic-loaded versions such as the G6128T-DS next to Filter'Tron models, and the 6120 range includes Dynasonic reissues too. Fender also sold Korean and Indonesian guitars under the DeArmond brand from around 1998, some with Dynasonic-style pickups, so the word DeArmond in a title doesn't mean the 1950s.
Dating and originality
Before 1965 a Gretsch serial is ink-stamped on a label, which sits in the control cavity on solid bodies and inside the back, seen through the f-hole, on most hollow bodies. It only gives a rough year, and Guitar HQ advises dating by serial and specs together. From 1965 the number moves to the headstock in a month, year and rank format, so 118243 is November 1968. On 1950s Gretsches the wire insulation often cracks and the wiring gets replaced, and the binding and glues don't age as well as on other makes, which can mean new binding or a neck reset. Ask what's been done. Because the pickup changed with the year, a 1956 6120 with Filter'Trons or a 1959 with Dynasonics needs a good explanation from the seller.
Which one to buy
If you want the 1950s DeArmond sound, look for a 1955 to 1957 6120, Duo Jet or White Falcon, and Guitar HQ rates the early single-cut White Falcons among the most collectible Gretsches. If you want the Filter'Tron sound, any original-pickup Gretsch from 1958 on has it, and a Country Gentleman, 6120 or Duo Jet is the classic choice. A HiLo'Tron Tennessean or Anniversary is a different, single-coil guitar, so buy one for what it is.
What to check in a listing
- Pickup type. Look closely at the pickups in the photos. A black face with poles and height screws is a Dynasonic, two rows of pole screws under a chrome cover is a Filter'Tron, a single row of poles is a HiLo'Tron and two blades is a Super'Tron.
- Cover stamp. Zoom in on the Filter'Tron covers. A blank cover, PAT. APPLIED FOR or 2892371 should match the year of the guitar.
- Inlays. Check the fretboard markers in the photos. Humptop markers fit 1957 to early 1958, and thumbprints arrived with the Filter'Trons in 1958.
- Serial label. Ask the seller for a photo of the label or headstock number. Its rough year should agree with the pickups and the trim.
- Wiring. Ask for a photo inside the control cavity or through the f-hole. Original or replaced wiring is fine if the listing says which.
- Binding. Look along the body and neck binding in the photos. Crumbling, shrinking or freshly replaced binding should be disclosed.
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