Originally Posted by brandtlj
Any idea why this might have happened?
If you take a screwdriver to the GFS-4 and open it up I'm 99% sure you'll see that other than switches it has zero
electronics. it is just a bunch of passive switches wired in parallel. Unlike other speaker selectors such as Adcom's GFS-3, GFS-6, and GFS-300 there are no resistors or anything else to possibly engage for impedance protection.
The GFS-4 is truly an audiophile grade loudspeaker switching system. It was designed to be the best product of its type available regardless of price.
During its design and construction particular attention was paid to the critical internal wiring and connections to insure that no degradation of sound quality would be audible in use.
Among the many important construction details in the GFS-4 are:
Extremely low internal resistance for minimum power loss; well below the contact resistance of the amplifier output connectors.
The highest grade of heavy-duty, gold-plated, solid-brass, 5-way binding posts, found only in the finest quality instrumentation-grade equipment.
Glass fiber epoxy (NEMA FR-4 grade) circuit board construction with the widest signal traces for minimum power loss; resistance of less than 0.001 ohms; will not degrade the damping-factor of any amplifier.
Oxygen Free Copper (OFC), internal wire jumpers of 12AWG stranded cable to insure signal integrity.
Massive nickel-plated-copper ground buss-bar; to insure lowest connection resistance between grounds.
Designed to be wired between your amplifier and the loudspeakers, it may be used to connect from one to four pairs of loudspeaker systems simply and conveniently.
You can play more than one speaker system at a time by pressing the appropriate button on its front panel.
If you own an Adcom brand amplifier, you can safely drive one or two pairs of 8-ohm or 4-ohm speakers up to any reasonably tolerable home listening level.
Should you intend to operate three or more pairs of speakers simultaneously, we suggest the use of an Adcom GFS-3 or GFS-6 Speaker Selector with Minimum Impedance Protection.
Should you own another brand amplifier, you should consult its instruction manual, or ask your audio specialist dealer for guidance, before connecting two or more speaker systems simultaneously to your amplifier."