My Humming Pioneer A400

I've got a Pioneer A400 GTE which has been humming on and off . So, obvious jokes aside, its time for me to sort it. The hum seems to originate from where the power enters the amp. It seems to stay at the same level regardless of volume. I wonder if anyone has suggestions about what this might be and a good place to have this put right. There is also a slight crackle when the volume knob is moved, but I imagine a contact cleaner will help with this. I also wonder if it is time for any other parts of the amp to be checked out/replaced - capacitors?. Besides the hum and some loose phono sockets at the back, the amp still plays beautifully.

I live in SE London and the more local the place the better. I'd rather go by recommendation than just take pot luck, though Pioneer mention a service place in Croydon which is one possibility.

 

The huming could be a vibrating transformer that has worked its way loose. The crackeling noise from the volume control is a sign that the volume potometre(sp) needs cleaning or replacing.

The 400 was a cracking amp so its worth keeping hold off I reckon they can give a modern day £300/£400 Marantz a good show. I think your amp needs a good service basicaly, it should cost well under £100 for the pot to be cleaned and the transformer repaired or may be replaced. If capacitors need replacing then there bill could come to more as HIFI grade capacitors are not cheap.

My amp needs a good service and its only two years old .

My sister has a Pioneer amp from the late 70's and its still working very well.

 

The loose phono sockets could be causing poor earthing and induce hum, out with your soldering iron methinks.

 

They do have heavy transformers in 400's and it wouldn't hurt to check the transformer bolts to the case are tight

 

potentiometer