The Broughton Audio Sentinel is an original design MOSFET overdrive and distortion pedal that also doubles as a preamp. It is an analog circuit built around a MOSFET clipping section, which the maker says provides rich harmonic content, and it splits its signal path between a clean path and a distortion path that are mixed back together with a blend knob1. It sits in the same family as other Broughton Audio drives such as the Ascalon, the Locust Star and the Chimera, and it belongs to the broader field of distortion pedals and overdrive pedals.
Status, price and warranty
The Sentinel is no longer in production. Broughton Audio states that the design is archived and is not in current production1. The design began as a one-off entry for a charity auction to raise funds for PCDH19 research, and the same design was later made in a small batch release1.
Because the Sentinel is archived, it may be hard to find new. The maker's page offered a Notify When Available option1.
The pedal was listed at US$185.00 on the maker's product page1. Broughton Audio covers its products for one year to the original owner, with warranty repairs handled by email at sales@broughtonaudio.com1. Returns can be initiated by emailing sales@broughtonaudio.com within 7 days of receiving the product; the buyer pays return shipping, and a refund is issued minus the shipping cost when the product is received in new condition1.
How the circuit works
The Sentinel's signal path is split between a clean path and a distortion path, and these signals can be mixed back together with the blend knob1. The maker says the pedal stands out for the rich harmonic content provided by the MOSFET clipping section1. Because it doubles as a preamp, it can also be used as a tone shaping stage rather than only as a drive1.
Controls
| Control | What it does |
|---|---|
| Gain | Controls the input level of the signal, increasing the harmonics of the distortion as well as the clean volume so blended levels stay proportionate1 |
| Blend | Mixes the clean and distortion signals back together1 |
| Low Clip | Controls the amount of low end sent to the distortion section and determines the character of the distortion1 |
| Bass | Active boost/cut, shelving type, centered at approximately 80 Hz, flat at noon1 |
| Middle | Active boost/cut, frequency variable from 200 Hz to 2 kHz, flat at noon1 |
| Treble | Active boost/cut, shelving type, centered at approximately 3 kHz, flat at noon1 |
The tone control knobs are active boost/cut controls with a flat response at the noon position1. The Low Clip knob is the pedal's character control: Broughton Audio describes low settings as giving a grindy, raspy tone, higher settings as bringing Rat territory, mid focused overdrive, and the top of the range as a full frequency wall of sound1.
Power
The Sentinel requires a DC power supply, which is not included1. It accepts 9 to 24 volts DC; the maker notes that higher voltages increase the headroom of the clean signal path but do not affect the overdrive character1. The supply should be a standard Boss style connector with center negative polarity, and the current draw is 20 mA1.
Questions
Is the Broughton Audio Sentinel still in production?
No. Broughton Audio states on the product page that the design is archived and not in current production with a Notify When Available option. The design began as a one-off entry for a charity auction raising funds for PCDH19 research and was later made in a small batch release.
Is the Sentinel true bypass?
Yes. According to Broughton Audio, the Sentinel has a true bypass switch, so the pedal's circuit is removed from the signal path entirely when it is switched off.
What does the Blend knob do on the Sentinel?
The Blend knob mixes the clean and distortion signals back together. The Sentinel splits its signal path between a clean path and a distortion path, and the Blend control sets how much of each is heard, letting you keep clean low end under the distorted signal.
What is the Low Clip knob on the Sentinel?
The Low Clip knob controls the amount of low end sent to the distortion section and determines the character of the distortion. Broughton Audio describes low settings as a grindy, raspy tone, higher settings as Rat territory, mid focused overdrive, and the top of the range as a full frequency wall of sound.
Does the Sentinel come with a power supply?
No. Broughton Audio states that the Sentinel requires a DC power supply, which is not included. It uses a standard Boss style connector with center negative polarity, accepts 9 to 24 volts DC, and draws 20 mA.
Sources (1)
- Sentinel, Broughton Audio
