How could an amp lose half its power ?

[istari knight]

My amplifier has lost half its power literally overnight !

There's no bass at all & I have to turn the volume control to 10 to get any volume....now it just sounds tinny & weak 🙁

Any obvious things to check ?

Much appreciated !

 

[Glowbug]

Power amp or integrated?

Does anyone else have access to the room, maybe a knob is turned somewhere it shouldn't be? 🙂

 

[istari knight]

Power amp or integrated?

Does anyone else have access to the room, maybe a knob is turned somewhere it shouldn't be? 🙂

Well, its actually a receiver so integrated I suppose 😀

Nope....No one else touched it - I fell asleep listening to it & when I woke it was like this 😕

model number : NAD 160a ... schematics are non existent but I do have low res pics that gives an idea of layout.... I can sort out some high res ones if anyone wants....

 

[istari knight]

Never mind, just found a buggered 2SD361 bjt transistor 🙄

 

[east electronics]

man ....you are looking in front of you a very hard task ...

this amplifier to put to work will need a total recaping ...amplifier is too old and beyond that still produce music be sure that is not working properly

all of these capacitors are not working properly ....

other than that is the carefull cleaning of all switches and pots

repacing a broken transitor will not cure the problem 100% find out why the transitor failed will do that ....

any capacitor that doesnt work properly in feedback or secondary psu might cause a lot of trouble

 

[h_a]

My amplifier has lost half its power literally overnight !

Happens if the output transistors are shot and the drivers drive the speakers, this often kills then the drivers next.

Any chance the outputs were shorted?

Have fun, Hannes

 

[east electronics]

no way hose half the power...... 1/10 of the power maybe

 

[AndrewT]

no way hose half the power...... 1/10 of the power maybe

yes and 1/10 the power (=-10dB) would sound like half volume.

 

[east electronics]

o cammon again Andrew !!!!! you know exactly what i mean .... the sound of the drivers only will sound so terrible that will be obvious


let us not make thinks like that a game of words ....how often have you seen tranistors go open almost never ...most of the times output transitors go shorted not open ....so no signal in the output ...

.....

 

[paulb]

I've seen some NAD gear with pretty shoddy workmanship. Hand-wired does not make it better.
Unless you can see something obvious to fix, I'd consider buying something else.

 

[istari knight]

Thanks for the information guys.....I have now recapped it & am just waiting for the replacement transistor......I'll report back as to whether its scrap or not 🙂

Cheers.