Class D and tripping circuit breakers

[Charles_b]

Hey guys, longtime lurker.

Sorry of this is a dumb question:


I'm rather impressed by the reviews and measurements of new class D amplifiers and are on the hunt for a new stereo/monoblock amplifier(s).


I have 2 class A monoblocks that are 1000 watts each. The plug socket they are plugged into is has a 10amp circuit breaker. 2000W draws 9.1 amps at 220V (I=P/V). Sometimes when I turn my amps on, the circuit breaker trips so, I will have to go to the breaker to flick the switch (which can get quite annoying and tedious after 5 attempts!).


Is a 1000w class D amplifier less likely to trip a circuit breaker than a 1000watt class A amplifier? If not, then I would have to concentrate my search on a less powerful amplifier (such as an amplifier based on the hypex nc400 board which uses a 600watt power supply).


Many thanks for your help!

 

[beren777]

I'd start with revisiting the assumption that you need 1000 watts per channel of amplification. What is your speaker sensitivity and how far do you usually sit?

 

[Charles_b]

I'd start with revisiting the assumption that you need 1000 watts per channel of amplification. What is your speaker sensitivity and how far do you usually sit?

Hey there.

Speaker sensitivity is 90db and I usually sit quite close at about 2.5-3 meters.

 

[PeterOo]

There are circuit breakers that react a bit slower and will not trip on short current peaks when you turn on the amps.
In the EU these are referred to as type/curve C or D.

MCB Trip Curves - B, C, D, K and Z trip curves- Made easy

Trip curves of MCB's (B, C, D, K and Z curves) tell us about the trip current rating of Miniature Circuit breakers. MCB trip curves

www.electricalclassroom.com

other people here can probably tell you if a class D amp (with a switching power supply?) would suffer from the same problems.

 

[DVDdoug]

Is a 1000w class D amplifier less likely to trip a circuit breaker than a 1000watt class A amplifier?

Yes.

I've forgotten some of the details but I think a true class-A amplifier draw the nearly same amount of power full-time, whereas a Class-A/B or Class-D amplifier theoretically draws nearly zero power when there is no signal. And in the real world, less power and wasted heat at lower volumes.

Of course no amplifier is 100% efficient and they do draw some power when idle, and there is generally a turn-on surge with anything while the capacitors in the power supply charge-up.

A Class-D amplifiers are very efficient with most of the energy going to the speakers and (relatively) very little energy wasted as heat in the amp itself.

Class A/B amplifiers not as efficient as Class-D but they are way more efficient than Class-A so they run (relatively) cool at low volume.

The plug socket they are plugged into is has a 10amp circuit breaker. 2000W draws 9.1 amps at 220V (I=P/V).

1000W into the speaker probably means 2000W from the power outlet. But since music is dynamic you're NOT putting-out 1000W into the speaker full-time, and the power supply capacitors tend to smooth-out the current-draw.

 

[SIY]

1000 W class A is unlikely. It would have to dissipate 2000 W per channel or more all the time, which would make for a toasty listening experience.

 

[Prana Ferox]

More relevant to the electrical conversation, your 1000w class A monoblocks (!) probably have enormous transformers and the inrush current on powerup is whats popping the breaker. That can be several times your normal max current draw. A good engineer would've added a snubber but I suspect that wasn't audiophile. Class D can use a transformer power supply but most tend to use SMPS.

I want to see these 1kW class A blocks, those things must need a dedicated air conditioner from the heat blasting off them.

 

[Charles_b]

There are circuit breakers that react a bit slower and will not trip on short current peaks when you turn on the amps.
In the EU these are referred to as type/curve C or D.

MCB Trip Curves - B, C, D, K and Z trip curves- Made easy

Trip curves of MCB's (B, C, D, K and Z curves) tell us about the trip current rating of Miniature Circuit breakers. MCB trip curves

www.electricalclassroom.com

other people here can probably tell you if a class D amp (with a switching power supply?) would suffer from the same problems.

Thank you, that is very useful to know. Perhaps I will pay an electrician to install one of these before I roll the dice on a new amp!

 

[beren777]

Hey there.

Speaker sensitivity is 90db and I usually sit quite close at about 2.5-3 meters.

Even with peaks of 105dB at 10 feet, you probably won't use more than 300 watts per channel. If you're usually listening at ~75 - 85 dB, you're not typically going to need more than 3-5 watts according to one calculator.

You may want to try out a VTV or Buckeye Purifi or Hypex NC502MP-based amp before paying an electrician to do anything.

 

[Vacceo]

1000 W class A is unlikely. It would have to dissipate 2000 W per channel or more all the time, which would make for a toasty listening experience.

You can grill the most revealing, veil lifting steaks on top!

 

[AdamG]

Thank you, that is very useful to know. Perhaps I will pay an electrician to install one of these before I roll the dice on a new amp!

Just a suggestion. But something you can try for free. When you turn on these 1kw Amps do they both power up at the same moment? If so, and as I suspect, try staggering the start up. Turn on 1 amp at a time with like a 10 second delay before turning on the second amp. If you have a universal Remote this delay sequence might be possible to program into the start up sequence.

 

[Charles_b]

More relevant to the electrical conversation, your 1000w class A monoblocks (!) probably have enormous transformers and the inrush current on powerup is whats popping the breaker. That can be several times your normal max current draw. A good engineer would've added a snubber but I suspect that wasn't audiophile. Class D can use a transformer power supply but most tend to use SMPS.

I want to see these 1kW class A blocks, those things must need a dedicated air conditioner from the heat blasting off them.

They are Vincent sp 991 plus monoblocks. They are massive, weigh 30kg each and they run very hot!

I can't listen to them presently as I'm waiting for a new pair new speaker relays to arrive in the post for one of them.

Part of my desire to replace with class D is the convenience-if they break and I'm unable to fix them, it really sucks to lug 30kg around to get them fixed somewhere! Also, with the energy saving I will be making, I will be able to finally afford my own private Jet!

 

[Charles_b]

Just a suggestion. But something you can try for free. When you turn on these 1kw Amps do they both power up at the same moment? If so, and as I suspect, try staggering the start up. Turn on 1 amp at a time with like a 10 second delay before turning on the second amp. If you have a universal Remote this delay sequence might be possible to program into the start up sequence.

I turn one on at a time. Sometimes, It takes 5 or 6 times to turn one on, other times, I can turn both on without them tripping once.

 

[AdamG]

Even with peaks of 105dB at 10 feet, you probably won't use more than 300 watts per channel. If you're usually listening at ~75 - 85 dB, you're not typically going to need more than 3-5 watts according to one calculator.

You may want to try out a VTV or Buckeye Purifi or Hypex NC502MP-based amp before paying an electrician to do anything.

I have been power monitoring my 2 six channel Buckeye 502mp Amps recently. When turned on 1 six channel 500mp amp draws 78 watts and after about 30 seconds drops t0 72watts. While playing a very loud movie neither amp ever exceeded 80 watts draw. The efficiency of these class D’s are pretty amazing. Nothing more than turning on an 75 watt light bulb.

 

[Charles_b]

Even with peaks of 105dB at 10 feet, you probably won't use more than 300 watts per channel. If you're usually listening at ~75 - 85 dB, you're not typically going to need more than 3-5 watts according to one calculator.

You may want to try out a VTV or Buckeye Purifi or Hypex NC502MP-based amp before paying an electrician to do anything.

From what people have said on this thread, then a class D would be less likely to trip than class a so your suggestion could be the way to go. many thanks

 

[Charles_b]

I have been power monitoring my 2 six channel Buckeye 502mp Amps recently. When turned on 1 six channel 500mp amp draws 78 watts and after about 30 seconds drops t0 72watts. While playing a very loud movie neither amp ever exceeded 80 watts draw. The efficiency of these class D’s are pretty amazing. Nothing more than turning on an 75 watt light bulb.

That's pretty interesting. What instrument do you use to measure that?

If you had to guess, what do you think would be the power draw on start up of a class a amp with the same amount of watts as your class D Buckeye?

 

[AdamG]

That's pretty interesting. What instrument do you use to measure that?

If you had to guess, what do you think would be the power draw on start up of a class a amp with the same amount of watts as your class D Buckeye?

I’m using your run of the mill power monitoring smart plug: (I did some minimal double verification monitoring with a hand held multimeter)

https://www.amazon.com/dp/B0B14C719T?_encoding=UTF8&psc=1&ref_=cm_sw_r_ud_dp_8YH6P3P8JJZDGNBY30E6

 

[Count Arthur]

Is a 1000w class D amplifier less likely to trip a circuit breaker than a 1000watt class A amplifier? If not, then I would have to concentrate my search on a less powerful amplifier (such as an amplifier based on the hypex nc400 board which uses a 600watt power supply).

Possibly, do your class A amps have a soft-start circuit?

Large transformers can create a lot of inrush current, a 1,000 VA transfomer: 200 A :

From Neurochrome's site: https://neurochrome.com/pages/the-ultimate-guide-to-soft-start-design

Soft Start module: https://www.diyclassd.com/product/softstart-module/38

 

[Charles_b]

Possibly, do your class A amps have a soft-start circuit?

I'm not sure that they do-is that what an above member called a "snubber"?

 

[Sokel]

I have Ice Power edge 1200as2 +300a2 (4 channels total) on an 10A plug with it's own 16A circuit breaker on the house board.
Never had a problem even if theoretically they go up to 3000 watts.
Go for D.