5-channel HT with higher power amplification levels for only front channels

[1audiohack]

Turn on is a big power hit with Adcoms for sure. When I sequence the 585 on it dims the lights in the master bedroom. Never tripped a breaker though.

I did a test and powered up three Crown CE2000's at once and tripped a 20A 120V breaker. The CE4000's have a Class D style power supply and soft start so I didn't try them.

The I-Tech's soft start also.

Not all breakers are created equal. There are "high mag" breakers for high current start devices like electric motors, AC compressors and such and would be a good match for power amplifiers. These are not available for all residential breaker boxes though.

One other thing that affects a breakers trip threshold is its trip history. They get softer when tripped often. You can also buy breakers that are switch duty but again, not for all residential boxes.

Barry.

[Robh3606]

Are they turning on multiples?? I do mine one at a time manually are they using triggers that are not timed??

Rob

[Mr. Widget]

.....lots of posts on blown 20 amp circuits - Adcom 7807, 7805, big Parasounds, big Krell, etc.... apparently, the biggest power draw is when the amps are first turned on.

I'm probably going to buy a few more Adcam 555s and call it a day....??

I have a pair of the biggest of the Parasounds and my lights don't even dim on power up. My 5hp Powermatic table saw does dim the lights a little on initial inrush, but it's a 30 amp 250V circuit so it's draw is rather substantial.


Widget

[rdgrimes]

Other than the added features that most people do not need, I see no benefit in buying the more expensive AVRs. I always spec the least expensive model with line level outputs and whatever other features that are needed to satisfy the system design.

Widget

Trouble is they always package the best DACs and analog boards in the flagship models. Plus the best auto-EQ routines, etc, etc.
If you have enough speaker and amp you can hear the difference in the better AVRs. There's no winning when you're chasing the last 5% of performance.

[rdgrimes]

I'm reading on the Internet about people who are blowing 20 amp breakers using larger multi-channel power amplifiers.

There's something like 3500W of rated power consumption, all turning on at the same time here and all on a single 15A circuit. The lights do dim a bit but I've never popped the breaker. (not from a lack of trying)

I used to have close to 5000W rated running on the same circuit.

[Mr. Widget]

Trouble is they always package the best DACs and analog boards in the flagship models. Plus the best auto-EQ routines, etc, etc.
If you have enough speaker and amp you can hear the difference in the better AVRs. There's no winning when you're chasing the last 5% of performance.

I think you need to take it on a case-by-case basis… Some "flagship designs" are really not that special sounding and are simply feature rich. Even if they have the best DAC chipsets, when you pump that through a mediocre analog opamp it kind of spoils the whole thing.


Widget

[robertbartsch]

.....the breakers in my electric box that are marked 10KA are really 20 amp circuits, as someone indicated above.... I turn my amps on one at a time... ....ahhhh, that is, since I read all the Internet posts on blowing out breakers... ....15 or 20 seconds apart, right?


Thanks....

[sebackman]

Hi Guys,

A bit OT I know, but may be of value to some.

-Just wanted to add a few things. Circuit breakers are magnetical devices and react to amps being drawn. There is a small solenoid in them and when too much amps are drawn the force of the solenoid pulls a small metal clip that trips the breaker.

Normally these are all “slow blow” characteristics in the US so there are really no alternative than to swap for a bigger if it blows often. In Europé there are 4 different “blow curves”, from fast to really slow.

These are also subject to large quality differences. A cheap one can trigger early so an alternative may be to buy a “known brand” breaker. Please see link below.

http://audiokarma.org/forums/index.php?threads/is-there-such-a-thing-as-a-slow-blow-circuit-breaker.269510/

All amps with switch mode power supply (light weight) do have in-rush protection/soft start to protect the electronics so they should not post aproblem.

For amps with conventional power supplies it’s the start-up of the transformer and potentially the charging of the capacitor bay that draws the amperage. There are many different types of transformers and they react differently. Most amperage is drawn by toroidal cores (round) and less by C-cores and E-cores.

The amp spike is only milliseconds long so you do not need to wait more than 1-3 seconds, the breaker is magnetic so there is now heat involved as with an older fuse type.

I built a three stage soft start for some big amps a while back and that had 3 seconds delay for stage two and three. It still sits there on the wall to remind me of all the stupid tests done over the years, but all my current amps,Crown CTS, have switch mode power supplies so it is not needed.

I would argue that most amps/receivers today do have some form in-rush protection. The more sophisticated have active electronics but most just a NTC resistor in series with the 120V/220V incoming. A NTC resistoris a small device that reduces resistance with temperature to almost zero. When the amp is turned on the resistor is maybe 20-50 ohms and as the current flows it gets warm and reduces resistance to zero. Hence the amperage spike is gone.



These look like a small black/gray disc (1/2” up to 1”) standing up and with two legs soldered into the PCB. Since this is an effective and cheap way to protect the electronics almost all “power electronics” today do have them. I would be surprised if your receiver does not have one, but it may be faulty.

If an amp blows speakers on turn-on or off it is normally faulty. On turn-on the speaker protection circuits should not release any signal before the amp is stable and on turn off the capacitor bay does not go flat immediately after turning power of so there should be ample of time to trip the speaker protection before any nasty things reaches the speakers. No amp should really release nasty spikes today if it is a good construction.

Attached is a picture of a NTC resistor and where it sits in a Crown K2amp.



If the breaker is 20 amps today, I would swap the breaker to a new “quality”breaker to start with.

Kind regards and sorry for the OT
//RoB