The phrase "a single knob and" is correct and usable in written English.
It can be used when describing a specific item or feature that includes one knob and is followed by additional information or items.
Example: "The device features a single knob and a touch screen for easy navigation."
Alternatives: "one knob and" or "a lone knob and".
Others have been puzzled by the design of the company's new interior control system, iDrive, which unifies a dizzying array of functions into a single knob and has left some drivers scrambling for the manual just to start a new BMW.
Moving from Reason to Logic and finally to Ableton Live, Spills was dropping advanced production within days of linking his Akai MPK to Live, controlling multiple effects with a single knob and processing found sounds into noisy oblivion.
Instead, it's controlled by a single knob that toggles through audio, navigation and vehicle functions.
Later models do not have the concept of stations and have a single knob to select a sound, along with the tuning control.
This simple tool, that fits in between an effect and the knob that controls it, allows you to map several parameters on one map, meaning several controls can be included on a single map, and subsequently controlled with a single knob.
"I could not turn a single knob on any door, or any faucet, or the stereo or the television set," Ms. Robertson wrote.
In another friend's apartment, hoping for a cup of coffee, I found myself outsmarted by a high-end glass cooktop that was designed without a single knob or switch.
"It was like disassembling a complicated machine only to discover that it's controlled by a single knob," Perron says.
In the middle of the black metal grille on front there's a single knob that's surrounded by a blue light when the speaker is powered on.
All guitar amps contain some form of equalization, often in the form of a single knob labeled "Tone".
And truth be told, many of the complaints about the 7 Series were about the car's interior and controls, including the bewildering I-Drive system, in which a single silver knob was toggled and rotated through a confusing menu of radio and heating configurations.
