From Jetter's website:
The Gold Standard concept is simple: Start by combining a Gold Shift and a Helium in a single enclosure then optimize the circuits for maximum performance and seamless integration when stacked. The result is an elevated level of performance that is, in a word, amazing.
The Gold Standard Side
The Gold side is operating very similar to the Gold Shift pedal on which it is based. The circuit was tweaked in several ways: The tonal center on the tone control has been shifted for a somewhat softer attack. Neutral is now at approximately 2 O’Clock. When the switch is selected to the Gold setting, the upper harmonics stay strong but the “bite” has been trimmed back a bit at higher gain settings. Overall, there is a slightly “woodier” tone as well. The “Shift” side of the switch is a smokier, slightly more compressed tone. This setting works particularly well with brightish guitars and amps. The “Shift” setting is also a great choice for achieving the elusive “violin tone”.
The Helium Side
The primary design goal of tweaking the Helium side was to achieve a natural, organic low-gain performance and to compliment the Gold side when stacked. The tonal center was shifted slightly and the overall voice was tweaked, particularly in the lower mids. This is most evident when using a neck pickup, particularly a Strat or Tele; the tones are absolutely stellar!