Long a standard in the Brit bike industry, the Tympanium regulator rectifier unit has proved itself over the years to be virtually bulletproof! Can be used on any 12v British bike with a single phase alternator including BSA A50, A65, Triumph twins, triples and singles, TR25W, T120 Bonneville, TR6, Tiger, T140, TR7, Norton Commandos, etc. All units supplied with easily understandable instructions.
Please note: Due the nature of the product, we unfortunately do not accept returns on bearings, service tools or electrical components. Please be confident about your purchase before ordering. If you have questions, please contact us.
Do you have questions about Solid State Regulators? Check out our collection link below:
Our Collection of Classic British Motorcycle Regulators Rectifiers
The product images shown are for illustrative purposes only and may not be an exact representation of the product received. Manufacturers occasionally make minor cosmetic changes to items, such as color, finish, label, or design. These changes do not impact the item’s function or compatibility. Please contact us if you have specific concerns regarding appearance.
The Tympanium regulator/rectifier (PN# TBS-4034) is a 12-volt, 120-watt, single-phase solid-state charging module. It replaces the original Lucas rectifier and Zener diode on alternator-equipped Triumph, BSA and Norton motorcycles. ong a standard in the Brit bike industry, the Tympanium unit has proved itself over the years to be virtually bulletproof. It works on positive-earth and negative-earth bikes, connects to 2-wire or 3-wire single-phase stators, and comes with easy-to-follow instructions.
Features of the Tympanium TBS-4034 Regulator/Rectifier
- Two parts in one: It does the job of both the Lucas rectifier (AC to DC) and the Zener diode voltage regulator.
- 12 volt, single phase, 120 watt: Matched to the standard Lucas-type 10-amp single-phase alternator stator.
- Positive or negative earth: Separate red and brown output leads let you set the polarity during installation.
- Four flying leads: Two yellow (AC in from the alternator), one red (B+) and one brown (B−).
- Solid state: No moving parts and nothing to adjust.
- Instructions included with every unit.
Fitment
The Tympanium unit fits any 12-volt British motorcycle with a single-phase alternator, including:
- BSA: A50 and A65 unit twins, plus 12-volt BSA singles and triples with single-phase alternators.
- Triumph twins: T100 and Tiger 500s, TR6 Trophy, T120 Bonneville, and T140 Bonneville and TR7 Tiger 750s up to 1978.
- Triumph triples and singles: T150 and T160 Trident, TR25W Trophy and other 12-volt unit singles.
- Norton: Commando 750 and 850.
Check your stator first. From 1979, Triumph 650 and 750 twins were fitted with the Lucas RM24 3-phase stator. Those bikes need a 3-phase unit such as the Podtronics 3-phase regulator/rectifier (TBS-4034AT). If you have fitted a 16-amp, 200-watt high-output stator, use the Podtronics 16A/200W regulator/rectifier (TBS-4035).
Installation Overview
- Disconnect the battery earth lead.
- Remove the Zener diode, or disconnect it and insulate its wire.
- Disconnect and remove the old rectifier.
- Bolt the Tympanium to a cool metal surface that gets airflow, or to a heat sink.
- Connect the leads as shown below, then reconnect the battery.
| Tympanium lead | Positive earth (stock British) | Negative earth |
|---|---|---|
| Yellow | Alternator lead | Alternator lead |
| Yellow | Alternator lead | Alternator lead |
| Red (B+) | Frame earth | Battery positive |
| Brown (B−) | Battery negative | Frame earth |
A battery must stay in the circuit, because this is not a battery eliminator. To learn more about how solid-state charging modules work, watch our video about solid-state regulators, or test your charging system with our 12-volt charging system diagnostic guide.
Please note: Due the nature of the product, we unfortunately do not accept returns on bearings, service tools or electrical components. Please be confident about your purchase before ordering. If you have questions, please contact us.
Do you have questions about Solid State Regulators? Check out our collection link below:
Our Collection of Classic British Motorcycle Regulators Rectifiers
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Frequently Asked Questions
What does the Tympanium TBS-4034 regulator/rectifier replace?
It replaces both the original Lucas rectifier and the Zener diode on a 12-volt single-phase charging system. The rectifier turns the alternator’s AC output into DC, and the Zener diode limits charging voltage. The Tympanium does both jobs in one solid-state unit, so the old rectifier and Zener can be removed.
Which motorcycles does the Tympanium regulator/rectifier fit?
It fits any 12-volt British motorcycle with a single-phase alternator. That includes BSA A50 and A65 twins, Triumph 500 and 650 unit twins such as the T120 Bonneville, TR6 and Tiger, 1978-and-earlier T140 and TR7 750s, Trident triples, the TR25W and other singles, and Norton Commandos. If you’re not sure your bike is single-phase, call us at 720-570-7884.
Does the Tympanium work on positive earth (positive ground) bikes?
Yes. It works on positive-earth and negative-earth systems. For stock positive earth, connect the red lead to the frame and the brown lead to battery negative. For negative earth, reverse them: red to battery positive and brown to the frame.
How do I wire the Tympanium regulator/rectifier?
Connect the two yellow leads to the alternator wires that went to the old rectifier. Either yellow can go to either alternator wire. Connect the red and brown leads to frame earth and the battery, according to your bike’s polarity. Then remove the Zener diode, or disconnect it and tape over its wire. The included instructions show both positive-earth and negative-earth wiring.
Can I use it with a 3-wire alternator stator?
Yes. On a 3-wire single-phase stator, join the two darker leads (green/black and green/yellow) and connect them to one yellow Tympanium lead. Connect the light-colored green/white lead to the other yellow lead. This gives you the stator’s full output all the time.
Will it work with a 3-phase stator on a 1979-on Triumph T140 or TR7?
No. The Tympanium TBS-4034 is a single-phase unit, and 1979-on Triumph 650 and 750 twins came with the Lucas RM24 3-phase stator. Use the Podtronics 3-phase regulator/rectifier (TBS-4034AT) or the Lucas universal MOSFET module (MUR25A), which handles single-phase and 3-phase stators.
Can I use the Tympanium with a 200-watt high-output stator?
It’s not recommended. The Tympanium is matched to standard 120-watt, 10-amp single-phase stators. If you’ve fitted a 16-amp, 200-watt stator such as the L.A.P. RM23, use the Podtronics 16A/200W regulator/rectifier (TBS-4035).
Can I run my bike without a battery using the Tympanium?
No. The Tympanium needs a battery in the circuit to smooth and store its output. For a battery-less setup, use a battery eliminator such as the Boyer Power Box (TBS-3572A).
Where should I mount the Tympanium regulator/rectifier?
Bolt it to a cool metal part of the frame or a heat sink, in a spot that gets airflow while you ride. Like the Zener diode it replaces, it gives off heat as it regulates voltage, so don’t enclose it or insulate it from the frame.
What charging voltage should I see after fitting the Tympanium?
With a healthy battery and stator, battery voltage should rise to about 14 to 14.5 volts at around 3,000 rpm and stay there. A reading well above that suggests a regulation or earth fault. A reading that never rises suggests a wiring, stator or rotor problem. Our 12-volt charging system diagnostic guide covers the tests.
Can I return the Tympanium regulator/rectifier if it’s the wrong part?
No. We don’t accept returns on electrical components, so please confirm your bike has a 12-volt single-phase alternator before ordering. If you have questions, call us at 720-570-7884 or text 720-260-4271.
*The product images shown are for illustrative purposes only and may not be an exact representation of the product received. Manufacturers occasionally make minor cosmetic changes to items, such as color, finish, label, or design. These changes do not impact the item’s function or compatibility. Please contact us if you have specific concerns regarding appearance.*
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