Class D amp long term reliability

[pma]

Complexity, density of components and radiated heat, local heat centers, quality of soldering, thermal management - this all affects the reliability. Simpler and colder is more reliable.

 

[egellings]

Yep. Fewer things that can go wrong is better, so long as design performance is not compromised doing so.

 

[caught gesture]

I clean out my integrated amp as well as my dac with compressed air every few years. Both have vents for cooling and the dust does get in. An electrical engineer told me many years ago that dust build up could shorten the life of electronics as it impedes the dissipation of heat. I don’t know whether this is true, but I have followed his advice and have not had any problems with audio components failing after almost two decades of use.

 

[egellings]

Keeping equipment certainly doesn't hurt at all, although I think that dust buildup would have to be pretty severe before it impedes cooling enough to cause excessive temperature rise.

 

[EJ3]

I clean out my integrated amp as well as my dac with compressed air every few years. Both have vents for cooling and the dust does get in. An electrical engineer told me many years ago that dust build up could shorten the life of electronics as it impedes the dissipation of heat. I don’t know whether this is true, but I have followed his advice and have not had any problems with audio components failing after almost two decades of use.

TRUE! Especially if you have pets (dogs, cats, birds, reptiles, etc [I guess fish wouldn't be a problem unless their aquarium leaked onto the wires or equipment] or smokers {or worse, pets & smokers}). I try to do an annual pulling the case covers & gently blasting (yes, I know those two words together are an oxymoron) the dust away. Every 5 years or so I have the electronics looked over by an extreme hobbyist or professional for swollen caps, etc. Usually it is 15-20 years or more before we find any issues. They get taken care of then. Inspected for anything else, if so, fix it also. Then it is back to the regular routine: annual cleaning, 5 year checkup. The only thing that I ever had go out on me that wasn't readily fixable was an AVR, made in 1990, which was my first (& only) Denon product. It didn't quite make it to 5 years before a greenish smoke wafted out of it. I did not bother to try & have it fixed, as I had never liked it's sound anyway. It was nowhere close to neutral.
Funny how, when the smoke gets let out of the wires, the magic goes away. EJ3

 

[caught gesture]

TRUE! Especially if you have pets (dogs, cats, birds, reptiles, etc [I guess fish wouldn't be a problem unless their aquarium leaked onto the wires or equipment] or smokers {or worse, pets & smokers}). I try to do an annual pulling the case covers & gently blasting (yes, I know those two words together are an oxymoron) the dust away. Every 5 years or so I have the electronics looked over by an extreme hobbyist or professional for swollen caps, etc. Usually it is 15-20 years or more before we find any issues. They get taken care of then. Inspected for anything else, if so, fix it also. Then it is back to the regular routine: annual cleaning, 5 year checkup. The only thing that I ever had go out on me that wasn't readily fixable was an AVR, made in 1990, which was my first (& only) Denon product. It didn't quite make it to 5 years before a greenish smoke wafted out of it. I did not bother to try & have it fixed, as I had never liked it's sound anyway. It was nowhere close to neutral.
Funny how, when the smoke gets let out of the wires, the magic goes away. EJ3

That is another benefit of a regular clean. It gives me an opportunity to look for any warning signs of a component going bad. Like you say, swollen caps, etc. I’m not a rich man but I have a relatively good system (all bought secondhand). I figure that some regular maintenance will help maybe with longevity.

 

[EJ3]

That is another benefit of a regular clean. It gives me an opportunity to look for any warning signs of a component going bad. Like you say, swollen caps, etc. I’m not a rich man but I have a relatively good system (all bought secondhand). I figure that some regular maintenance will help maybe with longevity.

It's kind of like Preventative Maintenance on a vehicle: Perhaps it will go a long time without PM (but that is not likely). It may not go a long time if one does the PMs but it is very likely that it will go far if the PMs are done.

 

[orchardaudio]

I had the Orcard Audio mono-blocks and unfortunately they were unplugged while playing audio and one of the amps blew! .. to be fair they did warn this could happen and I explained that it was my fault. Unfortunately Orchard Audio are unwilling to repair them and the best they could do is a 10% discount on replacement amp boards.
I would recommend Buckeye amps or similar at least you have an better chance to repair if they fail.

This would be a serious design flaw.

Absolutely. @orchardaudio probably needs to explain the failure scenario...

To elaborate in this particular case the speaker connections were disconnected while the amplifier was operating. It was not disconnected from the AC source. Disconnecting the amps from AC power source while they are operating will not damage them. Hence the amps will also not be damaged by power outrages.

The instructions for the amplifier are very clear. They are written this way to first protect the user from high voltages and secondly to help protect equipment from potential damage.

Regardless of amplifier brand, electronics that are live should not be "hot plugged" because damage may result, especially in high voltage high current devices.

I believe the design is very robust I have sold hundreds of these amps over the period of about 4 years and have had ~1% returns due to failures.

 

[restorer-john]

To elaborate in this particular case the speaker connections were disconnected while the amplifier was operating. It was not disconnected from the AC source. Disconnecting the amps from AC power source while they are operating will not damage them. Hence the amps will also not be damaged by power outrages.

The instructions for the amplifier are very clear. They are written this way to first protect the user from high voltages and secondly to help protect equipment from potential damage.

Regardless of amplifier brand electronics that are live should not be "hot plugged" because damage may result, especially in high voltage high current devices.

I believe the design is very robust I have sold hundreds of these amps over the period of about 4 years and have had ~1% returns due to failures.

I'm more interested in the specific failure mode in your amplifiers when disconnecting speakers at elevated power levels. This is not remotely a problem for Class A/AB transistor designs. Sure, old tube amps didn't like it much.

So tell me, do you consider the inadvertant disconnection of speakers something that is likely to occur in a domestic situation? I would say it is arguably one of the most likely scenarios and a reasonable consumer would expect their amplifer to survive such a common thing.

Are you specifically excluding damage from speaker disconnection as a reason to get out of warranty claims as the member in this thread suggested?

And, should someone wish to compare amplifiers on a comparator, will your amplifiers fail when the break before make relays switch between amplifiers at elevated levels?

 

[restorer-john]

You say the instructions for the amplifier are very clear. I disagree.

If damage to the amplifier can occur from disconnection, you need to specifically state that fact. You do not make any statements to that end.

Something like "Disconnection of loudspeakers during operation can damage the amplifier. Damage occuring from this is not covered under warranty".

Not sure it would stand up as a reasonable warranty exclusion, but saying nothing leaves you without a leg to stand on regarding demands for warranty remedy.

 

[pma]

So it would not survive my A/B test with a DPDT relay based A/B box? @orchardaudio , what is the value of quite nice results of @SIY measurements if the amp probably would not survive accidental disconnection of speaker when playing music? I would never recommend a product like this.

 

[LTig]

You say the instructions for the amplifier are very clear. I disagree.

View attachment 158020

If damage to the amplifier can occur from disconnection, you need to specifically state that fact. You do not make any statements to that end.

Something like "Disconnection of loudspeakers during operation can damage the amplifier. Damage occuring from this is not covered under warranty".

Not sure it would stand up as a reasonable warranty exclusion, but saying nothing leaves you without a leg to stand on regarding demands for warranty remedy.

I agree. Sure, the manual says do not operate with speaker disconnected but I think this is not enough.

I'm wondering what could be the reason of a damage in the first place. A voltage spike induced in the coils of the output filter comes to my mind. Wouldn't it make sense to add a protection circuit so the spike does not harm the amplifier?

 

[Roland68]

Keeping equipment certainly doesn't hurt at all, although I think that dust buildup would have to be pretty severe before it impedes cooling enough to cause excessive temperature rise.

Unfortunately, you are very much mistaken.
Professionally, I deal with both heat dissipation and thermal insulation (computers / servers, industrial equipment, high-performance light generation, industrial ovens up to 1800 °, high-temperature 3D printing, etc.). Half a millimeter of dust can be an excellent insulator, a whole millimeter even worse. If you cook or roast something nearby (one or two rooms further), the dust with the fat particles in the air becomes a perfect insulation layer. Heat dissipation through the ambient air can quickly be reduced by 20 to over 50%. At a component temperature of 30 ° that is not bad, but at 50 - 80 °?

 

[KingRolo]

To elaborate in this particular case the speaker connections were disconnected while the amplifier was operating. It was not disconnected from the AC source. Disconnecting the amps from AC power source while they are operating will not damage them. Hence the amps will also not be damaged by power outrages.

The instructions for the amplifier are very clear. They are written this way to first protect the user from high voltages and secondly to help protect equipment from potential damage.

Regardless of amplifier brand, electronics that are live should not be "hot plugged" because damage may result, especially in high voltage high current devices.

I believe the design is very robust I have sold hundreds of these amps over the period of about 4 years and have had ~1% returns due to failures.

So just to clarify one amp was accidentally disconnected from the outlet while powered up. It’s unfortunate because you are unwilling or unable to repair it.
I feel the product needs to have more built in protection features before I could recommend it, it’s almost like it was designed for a clinical type setting and not a home. Hence the reply to this tread.

 

[Trell]

ASR is a treasure trove of information of products to avoid, especially for niche products (like the above) where measurements and other data is very hard to come by.

 

[orchardaudio]

So just to clarify one amp was accidentally disconnected from the outlet while powered up. It’s unfortunate because you are unwilling or unable to repair it.
I feel the product needs to have more built in protection features before I could recommend it, it’s almost like it was designed for a clinical type setting and not a home. Hence the reply to this tread.

This was a complete misunderstanding on my part then. Please send me an email. I will get the amp repaired right away at no cost.

The amplifier shall survive being disconnected from AC power during operation. Many of my customers experience power outages all of the time which is essentially the same thing.

 

[restorer-john]

So just to clarify one amp was accidentally disconnected from the outlet while powered up. It’s unfortunate because you are unwilling or unable to repair it.

So we have Orchard audio saying one thing (disconnected speaker) and you saying another (disconnected power outlet).

Bottom line is this:

No commercially sold amplifier should fail in either scenario. Both situations are perfectly normal occurences, just as short circuits, overdriving, paralleled speakers, surges and spikes are common. Amplifiers have been protected from such typical aberrations for the last 60+ years.

 

[restorer-john]

This was a complete misunderstanding on my part then. Please send me and email. I will get the amp repaired right away at no cost.

This appears to be a better outcome.

 

[AdamG]

This appears to be a better outcome.

Well done John!

 

[antennaguru]

This is why I prefer separate components, versus integrating them!

1. Power Amplifier(s) external to the Loudspeakers.
2. Preamplifier external to Power Amplifier(s).
3. Moving Magnet/Iron Phono Cartridges with User Replaceable Stylus Assemblies.
4. Stereo Subwoofers with External Amplifiers/Controller.

I'm really surprised that the Hypex has such a short lifespan, as I have been using some IcePower modules on a few systems for as long as 5 years. My main system has a Class AB Power Amplifier that I bought new two decades ago.