Hamer Quad 12-String Basses

1978 Hamer Quad 12-string bass, the first 12 built by Hamer.

Hamer QUADRAPHONIC 12-String Basses

The first 12-string basses built by Hamer Guitars starting in 1978 are referred to as the Quads due to the quadraphonic electronics. All known Quads are displayed here. Others may exist.

“We went ahead with the 12-string bass and we wanted to make it stereo, and Tom asked if we could make it quadraphonic and we said sure so we built it with a pickup for each of the groups of strings. They were special coiled pickups that looked like half Strat pickups.”

“We asked Seymour Duncan to build a pickup with four outputs and we built a control box on the top portion of the body like a little mixing console / board. The crazier we could make it, the more outrageous… the better! Each group of strings had its own pickup, volume, treble boost and cut, bass boost and cut and a switch to select the frequency the EQ worked at. That bass ended up being refinished a few times. It went from a blonde / natural to an emerald green to finally black."  Jol Dantzig - 2001

Control cavity rout being chiseled out on the first Quad 12-string bass.

Three Quad 12-string bass bodies are in the center stack.

Quad Box 12-string bass interface.

The Quad Box interface had a canon-type connector on one end and four ¼" jacks on the top. This enabled you to split each string / pickup to a separate output to effects, amps, or to pan it between multiple amps. There is a separate ¼" jack on the bass for the normal humbucker pickup output.

“The quad had five outputs, one mono and one for each group of strings. There was the ¼" output jack, and a canon jack that was a low impedance five-pin output with four hot and a common ground like a microphone connector or a DI. I know Tom never used the quad outputs live, he always used the mono output that he plugged into a guitar amp." Jol Dantzig - 2001

“At the absolute most only ten Quads were ever made. They were such a pain in the ass to build and it was a hard enough sell being it was a 12-string bass. To this day I’ll show bass players the 12-string and they’ll say 'Wow, it's so much easier to play than I thought it would be!'' They just don’t view it as a viable instrument and let alone with the Quad it was kind of over the top. The Quad feature really wasn’t that useful. It was interesting when you played it alone. You could put the G string in the left channel and the E string in the right channel and the others in the middle, but there are other ways of doing that now. " Jol Dantzig - 2001


12-Knob Quad Basses

The first group of Hamer Quad 12-string basses include the 12-knob quadraphonic electronics. It is evident from the changes in features and details that a considerable amount of experimentation was involved in the building of these basses.

The First Hamer Quad 12-String Bass - 1978

Tom Petersson with the first Hamer Quad 12-string bass built in 1978. Apparently it tasted good.

This is the first Hamer Quad 12-string bass that was made. It was made for Tom Petersson of Cheap Trick and was first heard on the song ‘Heaven Tonight’ on the Cheap Trick album of the same name. It's distinctive sound was made famous on Cheap Trick's best selling album At Budokan.

The neck has no dots inlays. It is interesting is that the “Hamer” logo that had originally been positioned on top of the front pickup has been removed.

On the first few Quad 12-string basses a 4-saddle bridge was incorporated. Within a year this part had been replaced with an 8-saddle bridge.

The first Hamer Quad 12-string bass after it had been painted black.

An early published write-up of the Hamer Quad 12-string bass.

Tom Petersson with the painted Black Hamer Quad 12-string bass.

Pete Comita also played the Black Hamer Quad 12-string bass in 1980 and 1981.


1978 “Pawn Shop” Hamer Quad 12-string bass

1978 Hamer Sunburst Quad 12-string bass, serial # 0096.

This Hamer Quad 12-string bass was built in 1978 and is serial # 0093. It is in the Sunburst finish with an ebony neck and no dot inlays on the fingerboard.

The inscription "Tom Petersson Quadbass" is on the headstock. The current owner bought this bass at a pawn shop. It is still a mystery as to how it ended up there.


1978 Hamer “Trade Show” Quad 12-string bass

1978 Hamer Natural Quad 12-string bass, serial # 0119.

After disappearing from public view for many years, this bass was discovered at an auction in London, England in early 2020. It has been referred to as the “trade show” Quad 12-string bass because it was displayed at a 1978 musical instrument trade show in London. The bass looks to be in serious need of some tender loving care. The “inlays” on the neck are actually stickers.

“Nitebob” plays this Hamer Quad 12-string bass at the London show.

In the book The Ultimate - An Illustrated History of Hamer Guitars there is a description of this bass: “Although the instrument (Quad bass) was intended to be built for Petersson alone, Paul Hamer mentioned the bass to Jethro Tull's new bass player, John Glasscock, who was interested in the idea. At one point when Tull was in town, Hamer happened to have Tom's bass in the shop for some minor adjustments, so he brought it down for Glasscock to see.”

Photo taken at the London show.

“Glasscock was so impressed that he ordered one immediately. Glasscock's Quadbass was completed just before the 1978 British Musical Instrument Trade Show in London, so Hamer brought it along with him when he flew overseas to attend the show.”

“Hamer asked Glasscock if he could display it at Hamer's booth and Glasscock agreed. Martin Barre arrived at Hamer's booth to demo some instruments and, while there, The Who bassist John Entwistle happened along. He examined the bass and, excited about the possibilities of the instrument, ordered one for himself in the Explorer shape of the Standard.”

“Quad bass” is inscribed on the headstock.


Jon Entwistle’s Hamer Standard Quad 12-string bass

Thanks to Jol Dantzig at Hamer Guitars who provided this photo of the Hamer Quad 12-string bass that was custom built for John Entwistle of The Who. It is exceptional in that this Quad was made in the Standard style, which also would qualify it as the first Hamer Standard 12-string bass built.

Hamer Guitars employee Bill Thome and the 1979 Quad 12-string bass built for Jon Entwistle, serial # 0139. This photo was taken outside of the Hamer Shop in Palatine, Illinois.

This bass has a number of features that distinguish it from the rest of the Quads. Most obviously the switches and the 12 knobs for the quadraphonic circuitry are all at the bottom of the body instead of at the top. The two main knobs are positioned far forward. Although the body was routed for two pick-ups only one was actually included. It had 21 frets with a set neck. The custom double-dot inlays are set to the outsides of the neck with three inlays at the 12th fret.

The serial number of this bass is # 0139. Factory records show a completion date of January 25th, 1979. According to an interview given by Cheap Trick drummer Bun E. Carlos, Entwistle played this bass on the soundtrack for the movie Quadrophenia. The Who re-recorded much of the music from the album Quadrophenia for the movie soundtrack in April of 1979. Much of the re-recording involved strengthening the bass lines. Carlos claimed to have been present at a studio in Germany while Entwistle was recording with it.

A DiMarzio humbucking pickup was eventually added. Entwistle sold this bass in the 1980’s.


1979 Hamer Quad 12-string basses

These two Quad 12-string basses were built in 1979. The Natural finish bass is serial # 0143 and was built for bassist Dave Denisar, it was completed on late January. The Burst finish Quad is serial # 0144. Both are short 30½” scale with Bartolini pickups.

Both of these basses incorporated an 8-saddle bridge. At one time the Burst bass had been fitted with a custom 12-saddle bridge and strung Inverted, but it has been restored to its initial condition.

The Burst Quad serial # 0144 with a custom 12-saddle bridge and strung Inverted.

The headstock of the Natural bass includes the capitalized straight inscription “QUADBASS”.


8-Knob Quad Basses

Two of the three known 8-knob Hamer Quad 12-string basses.

Starting in 1980, Hamer considerably simplified their quadraphonic electronics circuitry. The quad electronics were redesigned from a 12-knob / 8-switch format to an 8-knob / 4-switch arrangement, and the switches were also moved from below the knobs to above them. Only three of the 8-knob Quad 12-string basses are known to exist.


1980 Hamer Quad Bass - Serial # 0378

1980 Hamer Quad Bass - Serial # 0378

This bass was made in the Cherry finish. It has star inlays on the 5th and 12th positions.


1980 Hamer Quad Bass - Serial # 0404

1980 Hamer Quad Bass -  Serial # 0404

1980 Hamer Quad Bass - Serial # 0404

This Quad 12-string bass was made in the Cherry Sunburst finish with the dot inlay neck. A checkerboard pattern is inscribed underneath the Hamer logo on the headstock.


1981 Hamer Quad Bass - Serial # 0426

1981 Hamer Quad 12-string bass in the ‘59 Burst finish and dot inlays, serial # 0426.

Hamer records show that the completion date on this bass was January 2, 1981. As was done in the previous Quad, a checkerboard pattern is inscribed underneath the Hamer logo on the headstock.