Here’s a mod I did to my compressor a while back…
The line pressure gauge that came with the compressor was rated up to the maximum pressure of the compressor…, which was something crazy like 200 PSI. So as a result the part of the gauge that you actually use is only 10% of the full range (full scale deflection), making it difficult to tell the difference between 15 PSI and 25 PSI.
So the solution was to buy a replacement gauge from eBay (for about a fiver) with a full scale deflection of 60 PSI. So now 20 PSI is a third of the full range of the gauge and it’s really easy to see where the needle is at airbrush pressures.
Not only that, I also bought some quick fit connectors and some 6mm pneumatic tube and moved the gauge from the compressor to a bracket bolted to the side of my desk.
So now my pressure gauge shows more of the working range for an airbrush, and I can see it easily without having to grovel under the desk.
BTW the compressor I use is a Bambi BB24V. These are mainly used in the dental industry and are practically silent. When it’s on it sounds slightly louder than a fridge compressor, and with the 24 litre tank it sometimes goes for days in between cutting in. These cost heading towards £400 new, but I snagged mine on eBay for £99 in good condition. Often these go for low prices online because people sell them “buyer collects”. So if one crops up in your area for around £100 I’d say snap it up because you won’t find a better modelling compressor.