Not all grounds are created equal.
There are four main categories that are often referred to as “ground” when it comes to an audio component. They are:
- Safety Ground
- Chassis and Interconnect Cable Shields
- Power Common
- Signal Reference
Each one is very important. And although we ultimately let our ears determine our final designs, we’ve found it useful to apply a few rules along the way.
Rule 0: Safety Ground
The safety ground keeps everyone alive in the event of a catastrophic failure. This is the green (or green / yellow) cable that makes its way through the building’s wiring to the circuit breaker panel and ultimately to the Earth.
Rule 1: No Ground Loops
There’s no excuse for a ground loop showing up in a single component. One way to ensure this is to ensure that each of the following sub-systems are connected to the system Star Ground point by one and only one path.
- All Signal References
- All Power Commons
- The shields of all non-galvanically isolated single ended inputs or outputs
- Safety Ground and Chassis
Rule 2: Balanced Shields to Star Ground
For balanced connections’ shields (think Pin 1 of an XLR cable), that shield should connect to the star ground.
Rule 3: Single-ended Shields to Star Ground
For single-ended connections, keep in mind that the shield represents the signal reference. Therefore, the shield must connect to the Star Ground as well.
Rule 4: Non-galvanically Isolated Circuits to Star Ground
Any circuit related to an input or output that isn’t galvanically isolated must have its signal reference connected directly to the Star Ground. For a player, then, there’s the Ethernet port (input) and a few optional outputs. The Ethernet input is galvanically isolated, meaning the wires of the Ethernet cable do not physically come into contact with the player, they are separated by a transformer. The Standard USB connection, on the other hand, does physically connect. That means the signal reference should connect to the Star Ground.
Rule 5: Each signal reference must be directly connected to its power reference.
Worded differently, no circuit can have its signal reference connected to its power common through another circuit’s signal reference or power common.
Rule 6: Buses are OK
Circuits may be grouped together with their signal references forming a bus, and one end of the bus should be connected to the Star Ground either directly or by a Star of Stars.
These seven rules form the foundation of our exclusive component grounding design philosophy. It is a way to create superior audio gear that sounds amazing and plays well with others.
We don’t know what other equipment will play a role in your listening chain. Some may be Class 2 devices (no third prong connection to earth), some may suffer from Pin 1 Problems (Neil A. Muncy introduced the “Pin 1 Problem” in a Journal of the Audio Engineering Society paper, Volume 43, Number 6, June 1995 Pages 435‐453).
Using these rules as a starting point ensures that regardless of the other gear in the chain, our gear will sound and perform at its best. And, therefore, so will your system.
Want to dive even deeper into the world of grounding? Read Dave Davenport’s article on Audio Component Grounding and Interconnection.