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Welcome to St. Louis Strings Bass B and C Extensions

Introduction | Bass Machine | C Extensions | Endpins | Bass Stand | Bass Buggie

Bass Machines Bass C Extensions
Slide C-Extension Gated B or C-Extension

These extensions are truly unique.  They are easy to install, easy to adjust and do not mutilate the scroll like other extensions.  

Our extensions are made of brass and help conduct the acoustic vibrations through the scroll.  Their construction and weight of 2.5 lbs. actually increase the volume and depth of sound on the “E” string after it is installed. Among the many jazz and classical professionals using our extensions are: Principal bass of Boston Pops, Principal bass of Indianapolis Symphony, and Principal bass New Orleans Symphony.

Slide C-Extension $450 each.  Extension with installation $1,150.

  • The brass extension with ebony fingerboard has a unique sliding, self-clamping gate.
  • The string glides effortlessly on rollers through the body of the extension and around the scroll.
  • The extension can be easily adjusted to fit on any bass without cutting into the scroll (see slide c-extension instructions, below).
  • Installation instructions
Bass Slide
Bass Slide
The Lever Arm is under spring tension and automatically clamps the attached Lever Foot on top of the string. The unclamping of the string is done manually by pressing the Lever Arm down, using the Thumbpiece below it as support for the hand. With the Lever Arm pressed down, the Gate easily slides along the length of the Gate Runway to any position. Any notes below the clamped Lever Foot are then fingered.
* The top of the scroll needs to be at least 1.5cm below the "neck projection line" (for standard use).
* The Finger board needs to be about 1cm in side thickness.


The top of the scroll needs to be at least 1.5 cm below the projected "neck projection line" (for standard use) (shown in the picture above in dotted blue-green). The finger board needs to be about 1 cm in side thickness. 

The Wood Shim and extra long Extension Body are cut down to fit individual scrolls. Instructions and all parts for installation come with the extension. A craftsman with hand plane and tool skills can do the work.

Gated B Extension $730 each. With installation $1,430.
Gated C Extension $680 each. With installation $1,380.

Bass Gate Bass Gate

The gated C-extension will still work even if the scroll is at or above the neck projection line and no cutting of the scroll will be needed; When our extension is on a bass with the scroll that is 1.5 cm below the neck projection line then all gates open and close on the string normally. This is done by using only the top two fingers of the left hand (and the thumb underneath the brass extension body). When the scroll is higher then the neck projection line then the C string is very high above the extension fingerboard due to the fact that the extension itself is resting on top of the elevated scroll. So you have to press the "C" string down with the bottom two (pinkie) fingers of the left hand before you can close the first gate with the usual top two fingers.

Once one of the gates is closed with this two step process then the "C" string is pressed down and any other gate can be opened and closed with the usual one step process. This extra first step is so quick that it won't interfere with the playing at all.

View installation instructions.

Extension Instructions
Bass Instructions
Read through all instructions before beginning any installation work.
1.   Take off nut.
2.   Cut off the E-string part of the nut. The finished (cut) edge of the remaining nut will be 2.5 mm from the center of the nut A-string groove. (See diagram)
3.   Glue the modified nut back on. (Save the unused piece)
4.   Unscrew the “stopper screw” at the end of the extension body.
5.   Place extension to the side of scroll so that the round part of the brass is centered over the scroll. Mark (on the extension body) and saw off where it extends past nut edge.
6.   Start cutting down the (extension) wood shim while making sure that the extension body continues the trajectory that the E-string would follow toward scroll.
7.   Bend the rear “L” bracket so that it will be flush with the back wall of the peg box.
8.   With the wood shim near final thickness, place the extension so it rests on the scroll and nut area. File end so that it butts-up cleanly to the end of the Bass fingerboard.
9.   Draw the Bass fingerboard curvature, 0.5 mm higher, on end of extension fingerboard. Hand-plane the extension fingerboard to match the curve of the Bass fingerboard.
10.   Cut a little notch for the C-string to go through on the top end of the extension fingerboard. (We have found that the extension itself doesn’t need a nut for the C-string to vibrate cleanly. You can, if you wish, place a piece of lizard skin in the notch
11.   Wind C-string through the extension onto the A-string tuning machine. Even minimum tension on the string will pull the extension body solidly and securely into place.
12.   With the string as a guide, final adjustments can be made by:
  a) Moving the top part of the extension slightly left or right so that the C-string will be centered on the extension fingerboard. Shape shim accordingly.
  b) Cutting down the wood shim so that the clearance of the C-string will be (measuring from the bottom of the string) 5.5 mm of off the bass fingerboard. If you have cut too much off the wood shim, don’t worry, you can place a thin piece of rubber between the
13.   Mark (with awl) the placement of holes on the rear “L” bracket and side “L” bracket where the screws will hold them against the back and side peg box walls respectively.
14.   Take off extension. Color the wood shim black and drill holes in the “L” brackets.
15.   Put extension back on scroll. Run the C-string through the extension.
16.   Drill holes into the peg box walls (through the holes in brass) and screw in “L” brackets.
17.   Slide on the sliding gate. Gage by eye how much needs to be cut of off the ebony foot.
18.   Carve ebony foot (glued to lever arm) to match the curve of the extension fingerboard.
19.   Cut a (C-string radius) groove along the length of the ebony foot so that it clamps straight down on top of the C-string.
20.   Super-glue lizard skin onto the ebony foot. (Overlap skin onto the sides of foot)
21.   Slide the sliding gate to its “E-stop position” so that the edge of the ebony foot lines up directly with the edge of the extension fingerboard. To secure the gate’s position:
  a) Drill and tap hole in the same channel that the original “stopper screw” was in.
  b) Screw in the “stopper screw”. ( Taking into account its surrounding plastic tube)
22.   Cut down the E-string side of nut (that was previously cut off) and glue it on the other side of extension as a decorative side. Cut notch to accommodate “stopper screw”.
Extension (with gates) Installation Instruction
Read through all instructions before beginning any installation work.
1.   Take off the strings.
2.   Take off nut.
3.   Cut off the E-string part of the nut. The finished (cut) edge of the remaining nut will be 2.5 mm from the center of the nut A-string groove. (See diagram)
4.   Glue the modified nut back on.
5.   Replace strings G and D. Wind the A string onto the previous E tuner.
6.   Place extension body along side the fingerboard and scroll.
7.   Draw curvature of scroll onto wood shim and rough cut out shape and place carved shim on top of scroll.
8.   Saw off excess extension body so that it butts up to end of the Bass fingerboard.
9.   If the sides of the bass fingerboard are thinner than 11mm then the bottom of the brass extension body needs to be filed down.
10.   Draw the Bass fingerboard curvature, 0.5 mm higher, on butt end of the extension fingerboard. Hand-plane the extension fingerboard to match the curve of the Bass fingerboard.
11.   Start final cutting of the (extension) wood shim while making sure that the extension body continues the trajectory that the E-string would follow toward scroll.
12.   With the wood shim near final thickness, place the extension so it rests on the scroll and (neck) nut area. Cut a little notch for the C-string to go through on the top end of the extension fingerboard. (We have found that the extension itself doesn’t need
13.   Wind C-string through the extension onto the A-string tuning machine. Even minimum tension on the string will pull the extension body solidly and securely into place. With the string as a guide, final adjustments can be made by:
  a) Moving the top part of the extension slightly left or right so that the C-string will be centered on the extension fingerboard. Shape shim accordingly.
  b) Cutting down the wood shim so that the clearance of the C-string will be (measuring from the bottom of the string) 5.5 mm of off the Bass fingerboard. You will be taking the C-string and extension on and off several times. If you have cut too much off the
14.   Find the right hole (on extension body) for the front “L’’ bracket .
15.   Screw both “L” brackets to the bottom of the brass extension.
16.   Put extension back on scroll. Run the C-string through the extension.
17.   Bend “L” brackets so that they are flush with pegbox wall.
18.   Drill holes and screw “L” brackets to pegbox walls.
19.   Place gates onto extension and regulate their height.
20.   Final placement of gates will be adjusted when the string is tuned.
 
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