hifi engine

Pioneer A400 Fault

hi to everyone on the hifiengine forum

I've got a pioneer a400 integrated amplifier and have owned it for the last 18 years and last week, it became faulty.

The fault that has occurred is that there is only sound coming out of the left channel speaker while the right channel speaker has no sound coming out of it at all.

the volume control is faulty too because when you turn the knob right down, there is still a volume of sound coming out of the left speaker.

the single channel problem applies to all of the component input connectors (such as the phono, line-in, tuner and the cd RCA)

why is the amplifier doing this and if there's anyone here who has experience of a400 maintenance, what is the problem and how do you fix it?

info about this would be great

thanks in advance


just to clarify this is the

just to clarify this is the original 400, not the 400x.

hope this helps


A400 fault

Hi Niall,

Have you tried giving it a dose of 'Servisol' Super 10 spray? I was amazed at the difference this made on my A300. There is a small hole on top of the pot casing, from memory. Not wanting to state the obvious either, but is it the left / right volume balance out of sync? Hope you get it working again.