Ageing Amplfier: Poor Sound or No Sound at all? Dead Unit?

[admin_exported]

I have not just come here to talk about murder; I have a big background with electronics too.

Replace all those inexpensive electrolytic capacitors without hesitation. They have a rated working life in hrs, they dry out over time and are usually the culprit in most faults. Remove and replace all as part of any standard service (except for very large ps reservior ones)

 

[matt49]

I have not just come here to talk about murder; I have a big background with electronics too. Replace all those inexpensive electrolytic capacitors without hesitation. They have a rated working life in hrs, they dry out over time and are usually the culprit in most faults. Remove and replace all as part of any standard service (except for very large ps reservior ones)

I see your post here crossed with my post to you on another thread. So you've said something about hi-fi. Good. Looking forward to reading more hi-fi-related posts from you.

 

[Anonymous]

I have not just come here to talk about murder; I have a big background with electronics too. Replace all those inexpensive electrolytic capacitors without hesitation. They have a rated working life in hrs, they dry out over time and are usually the culprit in most faults. Remove and replace all as part of any standard service (except for very large ps reservior ones)

I see your post here crossed with my post to you on another thread. So you've said something about hi-fi. Good. Looking forward to reading more hi-fi-related posts from you.

Step-by-step instructions on how to test a transistor or step-by-steps on how to create a political scandal that ruins a person's life.
Which would you prefer?

 

[toyota man]

I am not sure if this is changing the subject but I bout my Son an audiolab 8000a off ebay and although it works ok and sounds ok when you power up or down it makes a sort of sqeeking noise through the speakers because of this my Son leaves it swicthed on all of the time how would I go about replacing capacitors also there is an inbalance between left and right speaker at low volumes any help with this one would be good many thanks TM

 

[Anonymous]

I am not sure if this is changing the subject but I bout my Son an audiolab 8000a off ebay and although it works ok and sounds ok when you power up or down it makes a sort of sqeeking noise through the speakers because of this my Son leaves it swicthed on all of the time how would I go about replacing capacitors also there is an inbalance between left and right speaker at low volumes any help with this one would be good many thanks TM

You

We call this a de-thump feature. When the supply is first powered up the power supply capacitors take time to charge up to supply potential. It goes straight through the speakers as a DC voltage (great way to kill them)

Your amlifier either lacks or has a faulty de-thump circuit, which takes the speakers out of circuit (switches them off) -- for the first couple of seconds when the unit is powered up. It is essentially a timer.

 

[toyota man]

I am not sure if this is changing the subject but I bout my Son an audiolab 8000a off ebay and although it works ok and sounds ok when you power up or down it makes a sort of sqeeking noise through the speakers because of this my Son leaves it swicthed on all of the time how would I go about replacing capacitors also there is an inbalance between left and right speaker at low volumes any help with this one would be good many thanks TM

You We call this a de-thump feature. When the supply is first powered up the power supply capacitors take time to charge up to supply potential. It goes straight through the speakers as a DC voltage (great way to kill them) Your amlifier either lacks or has a faulty de-thump circuit, which takes the speakers out of circuit (switches them off) -- for the first couple of seconds when the unit is powered up. It is essentially a timer.

Thanks for that I would think its a big job to repair so I will suggest that as you say that he turns the speakers off when turning it on :cheers:

 

[tomlinscote]

My old but still working Sanyo 80's stack system does the same thing it has no de thump circuit, but it does have a speakers off button so I turn the speakers off while it is powering up (and down) and get no thump 🙂

I am sure that I have read on here before that certaiin amps might have been Audiolab, suffer from level imbalance at very low settings. In the 90's you could buy in line attenuators to reduce the signal going to the amp meaning you have to turn the volume up, ie out of the imbalance zone....

Tommo