Updated: 14.11.2025 (content, terms)
A fault in the Naim (or Xiam) amplifier in Bentley cars, which results in complete silence from the speakers, is most often caused by damage to sensitive electronic components on the main board. It is triggered by a voltage surge (for example from a “booster”) and leads to a constant current draw (approx. 1A), which drains the battery.
Complete silence instead of premium sound. A flat battery after a night parked up. If you own a Bentley with the Naim system and are experiencing these symptoms, your amplifier is probably damaged.
In a car of this class, such a fault should not happen. The “Naim for Bentley” system is a audiophile unit, but its electronics are extremely sensitive to sudden voltage surges - most often caused by jump-starting the car with a “booster” after a long period of standing.
As specialists in this particular fault, we explain how it happens and present an effective solution. Our offer is clear: refurbishment takes 1-3 days, you receive a 24-month warranty, and the cost is 4000 zł incl. VAT.
Most (90%) of these faults are identical. Buying a used amplifier, often priced at 4000–8000 zł, without full diagnostics is a serious risk - it may have the same defect or fail soon after fitting. Our refurbishment removes the effects of the damage and restores 100% functionality, which we confirm on a dedicated test bench.
How do you identify the Naim amplifier in a Bentley?
The unit has a distinctive black metal housing.
The most reliable identification is by checking the label and part number (Part NO) against the list below.
Identification details
- Manufacturer: Naim or Xiam (depending on version and production date)
- Car models: Bentley Continental GT, GTC, Flying Spur
- Model years: 2004 – 2017
- Part numbers (Part NO):
- 3W0035466
- 3W0035466A
- 3W0035466D
- 3W0035466E
- 3W0035466F
- 3W0035466G
- 3W0035466H
- 3W0035466J
- 3W0035466K
- 3W0035466L
- 3W0035466M
- 3W0035466N
- 3W0035466P
- 3W8035466
- 3W8035466A
- 4W0035466
- 4W0035466A
- 4W0035466B
- 4W0035466C
Main symptoms of the fault
The two most common symptoms are complete silence from the speakers and a constant current draw (approx. 1A), which drains the battery while parked.
1. Complete silence from the speakers
When the radio or infotainment system is switched on, there is complete silence. Although the radio in the centre console appears to be working properly (for example it displays the map and responds to touch), no sound - neither music nor navigation prompts - reaches the speakers.
2. Battery draining while parked
This is a more deceptive symptom. In the morning, the owner finds the battery completely flat, even though everything was fine the night before. After charging or replacing the battery, the problem returns after one or two nights. Diagnostics show that the faulty amplifier, after the CAN bus has gone to “sleep”, does not switch off correctly and continues to draw around 1A of current.
3. Sudden onset of the fault
The problem does not build up gradually (for example with crackling or the loss of one channel). The fault is sudden and complete. It often occurs immediately after an incident involving unstable voltage.
One of our customers described it like this:
“We repaired the radio from that same Bentley at your place - but after refitting the radio, you could hear that the amplifier had also been hit when it was started with the booster. Last week, after plugging a charger into the cigarette lighter while driving, no sound whatsoever came from the radio.”
Does this scenario sound familiar? Don’t wait for the battery to go flat again.
Causes of the fault - why does the Naim amplifier fail?
In 90% of cases, the cause is damage to sensitive electronics by a sudden voltage spike (the so-called “spike”). This most often happens when trying to start the car using a “booster” or a jump starter.
Scenario: Damage caused by a voltage spike
The mechanism behind this fault is almost always the same. A typical real-life scenario looks like this:
- The car (often used seasonally) stands unused for a long time.
- The battery discharges naturally.
- The owner tries to start the engine using an external jump-start device (“booster”).
- At the moment the booster is connected or starting is attempted, a sudden, momentary voltage spike occurs in the vehicle’s electrical system.
The electronics in the Naim amplifier are extremely advanced, but because of that they are also very sensitive to such voltage peaks. The voltage spike “burns out” key components on the main board, which immediately leads to failure - silence and the start of a constant current draw.
Now that you know the culprit is a voltage spike, you can see why buying a used unit without a full warranty is so risky.
Costs: Price, time and warranty
Refurbishment the Naim amplifier costs 4000 zł incl. VAT, takes 1-3 working days and comes with a 24-month warranty.
Price details
| Item | Value |
|---|---|
| Repair price | 4000 zł incl. VAT |
| Turnaround time | 1-3 working days (for repair and testing) |
| Warranty | 24 months (written) |
| Diagnostics | Free of charge (even if you withdraw) |
Comparison: Refurbishment vs Used vs New from the dealer
Refurbishment for 4000 zł with a 2-year warranty is the safest and most cost-effective option. A used unit costs the same (or more), but comes with only a 14-day start-up warranty, while a new unit from the dealer costs several thousand pounds.
| Option | Estimated price | Warranty | Risk |
|---|---|---|---|
| OEMatic refurbishment | 4000 zł incl. VAT | 24 months | No fault. Confirmation that the fault has been cleared (1A draw) on the test bench. |
| Buying used | 4000–8000 zł | 14 days (start-up guarantee) | High. No history is known. It may have the same hidden fault or fail when connected. |
| Buying new from the dealer | > 15,000 zł | 24 months | None. Most expensive option. |
Repair process step by step
Our process is designed for your convenience and peace of mind. The whole job (excluding transport time) is completed within 1-3 working days from acceptance of the quote.
1. Shipping and registration
Please contact us (by phone or via the form) for an initial quote and to arrange a date. Then all you need to do is safely pack the unit itself (without cables) and send it to our address.
2. Diagnostics and final quote (1-2 working days)
Once we receive the parcel, we carry out a full assessment on our test bench. We contact you by phone, confirming the diagnosis (e.g. constant 1A draw) and giving the final, guaranteed price of 4000 zł incl. VAT. If you approve, we repair it. If you withdraw, we return the unit with no diagnostics charges.
3. Refurbishment and testing (1-3 working days)
Once you approve, our technicians refurbish the main board, removing the effects of the surge. As a precaution, we also replace other components that we know may fail.
The unit then goes back on the test bench, where we check sound quality and, crucially, confirm zero current draw in standby.
4. Settlement and safe return
After successful testing, we pack the amplifier together with a written 24-month warranty. Once payment has been settled, we send the working unit back to you by insured courier parcel.
Technical details and diagnostics
As one of the few, we have a dedicated test bench that allows us to verify the fault 100% before and after repair. This is our key advantage, giving confidence in an effective refurbishment.
Our test environment
We do not diagnose blindly. We use a complete test bench that simulates the working environment in a Bentley – it includes the radio and the CAN bus. The power supply is connected on a separate, monitored line.
This allows us to measure current draw precisely in standby (after the CAN bus has gone to sleep). It enables us to confirm the fault beyond doubt (constant 1A draw) before repair and its complete removal (near-zero draw) after refurbishment.
How do you diagnose the amplifier yourself? (Current draw test)
This is the key diagnostic test you can carry out to confirm damage to the Naim amplifier, if you have basic knowledge and a meter (ammeter).
- Make sure the audio system and ignition are switched off.
- Wait several, or even a dozen or so, minutes for the CAN bus in the vehicle to go fully to sleep.
- Measure the current draw on the permanent supply (+12V) going to the amplifier.
A sound amplifier after the system has gone to sleep should draw near-zero current (in milliamps). If the meter still shows a constant current draw of 1A (one amp), this is a classic sign of damage.
In extreme cases we have come across, this draw can reach as much as 2A, which leads even faster to a completely flat battery.
Warning: Carrying out this test requires basic knowledge of automotive electronics. If you do not feel confident, have the diagnostics carried out by a workshop or contact us.
FAQ – Frequently asked questions
Here are the answers to the 7 most common questions about repairing Naim amplifiers in Bentley.
About the author of this article
Article prepared by the workshop's technical team. We specialise in advanced diagnostics and repair of factory amplifiers and radio navigation systems, including repairs of Naim for Bentley cars products.
Restore sound in your Bentley – book a repair
Don’t risk buying an expensive used unit or paying a many-thousand-złoty bill at an authorised dealer. Order a professional refurbishment with a 24-month warranty and be sure the current drain problem is resolved.
Contact us for a free quote or send the parcel using the shipping instructions.
