blown fuses

PrimaLuna products have a main fuse that is housed inside a small compartment just below where the power cord plugs in.

If a main fuse fails, it’s usually for a reason. Sometimes, that fuse will blow due to a surge or spike in electrical current flowing into the amp. But more often it's because of tube failure that can't be detected by the Adaptive AutoBias circuit like a Heater/Cathode short.  In preamps and CD players, it's usually a 5AR4 tube.  In amplifiers, it would more likely be a power tube (EL34 or KT88) but could also be a small signal tube (12AX7 or 12AU7).  If none of these tubes have shorts, then the unit should be checked by a qualified technician.   

It’s okay to replace the main fuse one time, BUT IF THE FUSE FAILS AGAIN YOU NEED TO STOP and contact your dealer or PrimaLuna. Fuses fail for a reason- that has to be corrected. Continuing to replace a fuse that blows can result in damaging the unit.    

We recommend Littelfuse branded fuses, but other brands are fine as long as you use the correct amp rating. The main fuse is a slow blow fuse, also called a time lag fuse. If you install the right fuse value, but it is a fast blow, it will fail instantly. Make sure you use slow blow.

There are two pieces of information you need to know when changing fuses: The amperage rating, and the physical size.  All PrimaLuna amplifiers use the same size fuse; 5mm x 20mm. This is a very common fuse size, and should be easy to find at any electronics or hardware store.

The information below about fuse amp rating is for North America only! If you live outside North America, contact your dealer for fuse information.

DiaLogue Premium integrated amps and power amps use 2.5 Amp slow blow fuses.  All PrimaLuna Preamplifiers and CD Players use 1 Amp slow blow fuses. 

It should be noted that the ProLogue Classic Integrated, as well as the ProLogue Premium Integraded and Power Amps were under-fused. We have since changed their fuse requirements from a 2.5 amp slow blow, to a 3.15 amp slow blow. Disregard the label on the amp and the information you may have in your owner’s manual.