NEW! Potentiometers for left handed basses are now available! Select the "lefty" option in the variations.
PREAMP-ONLY ALSO AVAILABLE! If you're looking for just the preamp, please see my other listing here: https://www.ebay.com/itm/226047833560
PREAMP WITH CONTROL PLATE ALSO AVAILABLE! If you're looking for the preamp already mounted onto a control plate, please see my listing here: https://www.ebay.com/itm/227253108086
PEDAL VERSION NOW AVAILABLE! If you have a passive StingRay and want to make it active, this is the pedal for you! Please see my Ray in a Box listing here: https://www.ebay.com/itm/226732250469
Overview:
This is a reproduction of the classic late 1970s Pre-Ernie Ball Music Man StingRay 2-band preamp. Unlike all of the other reproductions I've managed to find online, this one is made with modern manufacturing methods and uses screw terminals to easily attach connections without soldering.
I'm a bass player and computer geek that's a huge StingRay fan, so I decided to design a preamp to recreate the vintage late 1970s StingRay sound - but modernize it and make it easier to work with.
My StingRay preamps come in four products:
- Preamp kit (this listing) - everything you need to upgrade your existing bass' electronics (potentiometers, audio jack, battery clip, wiring).
- Preamp only - replace an existing preamp and reuse all of your existing wiring and potentiometers. https://www.ebay.com/itm/226047833560
- Control Plate kit - the preamp, potentiometer, and jack already mounted to a control plate and ready for install! https://www.ebay.com/itm/227253108086
- Ray in a Box (pedal version) - If you have a passive StingRay and want to make it active, this is the pedal for you! https://www.ebay.com/itm/226732250469
The preamp kits come with the option of potentiometers with 15mm (for control plates) or 18mm (for rear control cavity) shafts.
Both of the kits also have the choice of vintage spec potentiometers (A25K volume and no center detents for bass and treble) or modern (standard) spec potentiometers (B25K volume and bass/treble pots with center detents). Neither of these options will affect the tone. Most people will want the modern spec as the detents make it easier to dial in your settings. The vintage spec pots are mostly for customers that are restoring vintage StingRays or who favor the old style. Left handed potentiometers are available as well, in both modern and vintage specs.
Design goals:
- Must reproduce the exact circuit used in late 1970s StingRays
- Must use the original, now discontinued LM4250CN opamp that's key to the distinctive sound and phenomenal battery life. I've installed the opamp in a socket so it was never exposed to the heat of a soldering iron. This also allows one to experiment with alternative opamps should you desire. Note that any other opamp must match the LM4250's pinout or you risk shorting out your opamp or board.
- Use screw terminals instead of soldered on wires to make installation easier
- Incorporate modern surface mounted electronics
- Attractive silk screening with clearly labeled terminals
- Incorporate a 1kΩ protection resister between the output jack and the LM4250CN opamp. Music Man attached this in between the output jack and the opamp to protect it from shorts that in rare circumstances could fry it. Other reproductions do NOT include this and it must be soldered on separately.
Preamp characteristics:
There are other replicas available online, some with the LM4250CN opamp and some with a substitute, but none that I've found met all of my requirements.
The preamp has the following characteristics:
- Bass boost/cut (+14dB/-7dB at 40Hz)
- Treble boost/cut (+20dB/-16dB at 10kHz)
Preamp dimensions: 49mm x 17mm x 11mm
What's included:
The preamp kit (standard) includes:
- MMSR77 preamp
- B25K (volume) linear taper potentiometer
- A100K (bass) audio taper potentiometer with center detent (C100K for left handed kits)
- C1M (treble) reverse audio taper potentiometer with center detent (A1M for left handed kits)
- Potentiometers come with 15mm (for mounting on control plates) or 18mm (for rear control cavity basses) shafts
- Quality stereo audio jack, wired to preserve battery life
- Chrome metal knobs that press on
- 9V battery clip with included Wago connector (so no additional soldering is needed should you have an existing 9V connector)
- Pre-cut and soldered extra-long wiring, which can be easily shortened to your needed length
The preamp kit (vintage) includes:
- MMSR77 preamp
- A25K (volume) audio taper potentiometer (B25K for left handed kits)
- A100K (bass) audio taper potentiometer without center detent (C100K for left handed kits)
- C1M (treble) reverse audio taper potentiometer without center detent (A1M for left handed kits)
- Potentiometers come with 15mm shafts (for mounting on control plates)
- Quality stereo audio jack, wired to preserve battery life
- Chrome metal knobs that press on
- 9V battery clip with included Wago connector (so no additional soldering is needed should you have an existing 9V connector)
- Pre-cut and soldered extra-long wiring, which can be easily shortened to your needed length
Installation notes (general):
This is an unusually designed preamp as Leo Fender designed it to obtain a particular sound. Thus, to recreate the late 1970s sound exactly the preamp needs to be paired with the following:
- 25kΩ audio (log) or linear taper potentiometer (A25K or B25K). The type of taper won't affect the sound, just the volume curve. Early StingRays used audio tapers, Music Man switched to linear tapers in the early 80s.
- 1MΩ reverse audio (rev log) taper potentiometer (C1M) - A1M for left handed.
- 100kΩ audio (log) taper potentiometer (A100K) - C100K for left handed.
- Music Man style humbucking pickup wired in parallel with around 1800Ω resistance. Nordstrand MM4.2 and MM5.2 pickups are wired to the exact late 1970s specifications and perform very well. Aguilar AG-4M and Seymour Duncan SMB-4A pickups also work great.
There are other replica pickups around, and the circuit will still sound great if you use a higher resistance pickup as the ceramic pickups found in lower-end Sterling by Music Man basses, but it won't necessarily have the exact sound.
When wiring, see the included image for which lug on the potentiometer is the wiper, CW (clockwise), and CCW (counter clockwise). Do not attach a battery until all components have been attached.
This preamp should fit easily into basses with large control cavities or rear cavities (such as 5 string StingRays, StingRays with double humbuckers, and others). It will also fit easily in 4 string StingRays with crescent shaped control cavities, though you will probably want to trim any excess wire (if using the kit). Due to slight differences in routing between different models you may have more or less room.
Shielding your control cavity and pickup cavity are highly recommended. Active preamps that boost treble can also boost noise in your circuit coming from broadcast signals, poor quality power, ungrounded pickups and bridges, and other sources.
There are more detailed manuals and other information online at my website.
Final notes:
Unfortunately I do not usually accept returns or refund requests as it's easy to damage the preamp if you're careless or don't know what you're doing. However, I did design this circuit to be as durable as possible. Please contact me should you have any questions or issues and we can work through them together. I want your project to be a success and for you to be happy with your tone.
Screw terminals on the preamp require a 1.5mm precision flathead screwdriver to tighten and potentiometers require a 10mm and 1/2" wrench to tighten (adjustable wrench is fine).