Heating receiver Options

[2E7AH]

I have this problem in a friend's house with old Hitachi SR-502 receiver (you won't find any spec on Google [edit: actually there is]) and it has around 250-300W power on which are feed special Sony speakers that can't play very quiet music (in defect) if you don't touch bass membrane, but are liberally fired by receiver as they are like really big > 1m hight (not saying power)

Problem is that receiver starts to smell like something is on fire if playing loud music. It's really hot summer here and air capacity is tighten, humidity like in rest of EU, but who knows the graph when it is enough (virtual temp in another post). Also provoking temperature is not problem - fire match and whole room will go some point of degree high (so to speak). So I'm not sure if we push receiver to edge as I can't touch it by hand - it's really hot, but it's not first time, only I don't want to see it's last time in near future.

Any experiences, when is enough?

This post has been edited by 2E7AH: Jul 25 2010, 19:01

[DVDdoug]

If the unit is too hot to touch, that's scary! It might help to set-up a fan to blow air over (or into) the unit. If there are heatsinks, maybe you can increase the airflow over the heatsinks. If you're handy with electronics, maybe you can install a fan inside the receiver (like a computer fan).

Maybe on hot days, you can put an ice-pack on it! (Not regular ice, but one of those sealed things that won't leak.)

I suppose the best advice is to take it to a service shop and have it checked-out!

Some amplifiers/receivers have over-temperature protection and will shut-down when they overhheat (and recover when they cool down). But not all amplifiers have this, and if a transistor overheats it can burn-out!

There is a rule-of-thumb (general guideline) that if a transistor is too hot to touch, there's something wrong. That's the transistor itself, not the heatsink or the case of the reciever, which should not be as hot as the transistors.

It's possible that something's gone wrong with the receiver (like a voltage regulator burning-out) and that's causing it to overheat. But, that's unlikely. If something like that goes wrong, the unit will normally quit working. (If the regulator goes out, it can take-out the output-transistors.)


If I recall correctly, an amplifier* will dissipate more power/heat internally than it puts-out. So, there is more than 200W of heat being generated internally. There is always an amount of heat generated and the unit should be designed to dissipate that heat (heatsinks, air-flow, fans, etc.).





*Class B or class A/B design. "Switching" designs can be more efficient.

[2E7AH]

Thanks for your reply DVDdoug,


This post has been edited by 2E7AH: Jul 25 2010, 20:28