GAS 4 Amp Pro Step Controller - Silent 5-Step AC Fan Speed Control
Best for: growers who want reliable, silent manual step control over a single AC extraction fan without the clicking or buzzing cheaper controllers produce.
Our thoughts
Step controllers get a bad reputation because so many cheap ones click loudly between speeds or make your fan hum at low settings. The Pro Step Controller's transformer-based design with solid-state relays avoids both problems - genuinely silent transitions, no fan buzz. If you just want manual control that behaves properly, this is the straightforward option.
The G.A.S 4 Amp Pro Step Controller gives you easy, manual control over your extraction fan speed, helping you dial in your grow room environment and keep noise down without any complicated programming. It uses digital controller technology with solid-state relays to create a five-step transformer, avoiding the audible clicking between speed steps that cheaper controllers are known for.
Because it's transformer-based rather than a simple triac dimmer, there's no humming or vibration from your AC fan even at the lowest speed setting - a common complaint with basic speed controllers. It comes with a 4 metre ready-wired temperature sensor and two 1.8 metre ready-wired mains cables (one for the fan supply, one for a heater supply if you're using one), and is built in Europe to a consistent quality standard. It's rated to handle fans up to 4 amps.
How it compares
This sits as the manual-only entry point below the Pro Plus version in G.A.S's step controller range.
- Versus the G.A.S 4 Amp Pro Plus Hybrid Controller: the Pro Plus adds an integrated heater control output on top of the same silent step technology; the standard Pro Step Controller is fan speed control only.
- Versus a basic triac-based speed controller: triac dimmers are prone to humming and vibration at low speeds; the Pro Step Controller's transformer-based steps avoid this.
- Versus the RAM Varispeed controller: RAM's version offers similarly straightforward manual speed control as a budget option, without the five discrete steps G.A.S's transformer design provides.
If you just want manual speed control that's genuinely quiet, this covers it without paying for automatic thermostatic features you may not need.
Usage guidance
Installation is wired rather than plug and play.
Installation
Wire in the supplied mains cables to your fan supply (and heater supply if applicable), and position the 4m temperature sensor centrally in your grow space.
Setting fan speed
Select your desired step from the five available speeds to set your extraction rate manually.
Noise check
Run through all five steps once installed to confirm silent, click-free transitions and no fan hum at your chosen setting.
Technical specifications
- Control type: Manual 5-step AC fan speed control
- Manufacturer: Global Air Supplies (G.A.S UK), built in Europe
- Fan current rating: 4 amps
- Technology: Transformer-based steps with solid-state relays, silent transitions
- Included cables: 4m wired temperature sensor, 2 x 1.8m wired mains cables (fan and heater supply)
- Noise: No audible clicking between steps or fan humming at low speed
Who this is for
- Growers running a single AC extraction fan up to 4 amps
- Anyone who's had a cheap step controller click or buzz and wants a quieter alternative
- Growers who prefer manual step control over automatic thermostatic adjustment
Best suited to single AC fan setups where manual control is preferred over automatic temperature response.
Our take
This is proper construction and reliable, quiet step control rather than a gimmick - it does the one job it's designed for without any of the usual step-controller annoyances.
If manual control is what you're after, this is proper construction and light control at a price that makes sense.
