The original Symphony I/O chassis uses a thermal sensor and cooling fan to maintain a temperature that helps the Audio Converter cards to provide its amazing and world-renowned audio quality. Since A/D and D/A conversion generates heat, the cooling fan in a Symphony I/Owould spin faster and therefore louder in units equipped with more conversion channels such as a 2nd module card.
As of late 2012, all new units feature a modified chassis design to help maximize air flow, thus helping reduce the fan speed and the amount of time that it is on. For chassis manufactured prior to this design change, Apogee offered a magnetic strip that can be easily attached to the left side of the unit (when viewing from the front) to block the vents, producing the same result as the new modified chassis design.
In early 2015, the fan was changed to the Sanyo Denki 9S0612F401 which some users report is a bit quieter than the previous model. Apogee does not have these available for purchase, but end-users can look for this model on the open market.
A new Symphony I/O MkII chassis was released in 2016 featuring an all new design with front-facing vents over the I/O module cards, and a special new fan that is virtually silent (note this new fan is not compatible with the original Symphony I/O). Nearly all the original Symphony I/O converter cards are compatible with the Symphony I/O mkII chassis, making it easy to upgrade. See your favorite music gear dealer for pricing.
Additional questions about this new model can be directed to our Technical Support Department: https://apogeedigital.com/support/apogee-technical-support-form