How many watts does an amp use?

[Old Garage-Bander]

thanks for the reply. I sent a message to the guys at Mark Bass and they replied that I need a 600watt minimum. Now I'm not doubting the guys there but 600 for a 500 watt amp? From all the posts that I read, the majority say that you need a heck lot more than that. I am not at the liberty to check out the Mark Bass back panel since I am nowhere near any dealer so that will have to wait till mid January.

As for the internal voltage selector, I am surprised about this one because the site says that it's made for specific regions. Anyway I'll ask that once I am back in Japan when I can see one in person.

If all fails, I will stick to the Tec Amp, but as many would say, you just gotta have more toys! LOL All GAS aside, I know that Phil Jones comes with a different votage selector and so does TC electronics on some of their stuff. It limits my options for different amp heads but as you mentioned transformers are a headache.

Anyway thanks for the info once again.

You were probably talking to the engineer. He knows how much more the speaker will take above its rated value.
On the other hand, you want to add margin to the margin. An 800 watt speaker is cheaper than a 600 watt speaker and an 800 watt speaker. You said they said 600 watt "MINIMUM."
Ask an engineer if a glass is half full or half empty.
He'll just tell you that the glass was not designed to the proper capacity specifications.

 

[Downunderwonder]

Didn't he even try to electrocute an elephant once?

I only remember from highschool that some dork tried hard to push DC distribution and lost out for obvious practical reasons. Eddison may well have been that dork but I think would remember any mention of electrocution of elephants. I guess they gave us a sanitised version in 1984.

 

[pravus]

Didn't he even try to electrocute an elephant once?

He didn't try. He did it. It's on video. ... EDIT... as I see further down.

 

[pravus]

True! But compared to J. P. Morgan, Edison was a saint. Morgan strong-armed both Edison and Westinghouse--Morgan had far more money for lawyers, so he could sue anybody he wanted into submission.

I know we won't see eye to eye on this but a man who will publicly destroy animals as a competitive strategy is more evil than a man with money on his mind in my book. One is at least a little more typical than the other and I know how to deal with finance types.

 

[Old Garage-Bander]

I only remember from highschool that some dork tried hard to push DC distribution and lost out for obvious practical reasons. Eddison may well have been that dork but I think would remember any mention of electrocution of elephants. I guess they gave us a sanitised version in 1984.

If you read 1984 in High School, you got the sanitized version.
Ironically, the story was about the government sanitizing what you read and how you think.
I wonder what Oceana would have made of the interwebs?

 

[Mark Reccord]

what the fudge?! I know back then, they had different set of rules but come on! This is ridiculous. I did hear that Edison was a total dick but that just confirmed it.

= 100,000,000
I have read many books about tesla and it sums it up. Edison was not a nice person.

I did a technology and society course when I did my EE degree and we spent quite a bit of time on the Tesla/Edison/Westinghouse AC vs. DC thing. Until then I didn't really know the history. I had held Edison in pretty high regard until then. Since then, I've become a bit of a Tesla buff. We share a birthday!

But yeah, Edison slandered anyone who went up against him hardcore.

thanks for the reply. I sent a message to the guys at Mark Bass and they replied that I need a 600watt minimum. Now I'm not doubting the guys there but 600 for a 500 watt amp? From all the posts that I read, the majority say that you need a heck lot more than that. I am not at the liberty to check out the Mark Bass back panel since I am nowhere near any dealer so that will have to wait till mid January.

As for the internal voltage selector, I am surprised about this one because the site says that it's made for specific regions. Anyway I'll ask that once I am back in Japan when I can see one in person.

If all fails, I will stick to the Tec Amp, but as many would say, you just gotta have more toys! LOL All GAS aside, I know that Phil Jones comes with a different votage selector and so does TC electronics on some of their stuff. It limits my options for different amp heads but as you mentioned transformers are a headache.

Anyway thanks for the info once again.

A 600VA transformer is fine for that amp. If you go back and read what @agedhorse posted I think it will make sense as to why. Even if you took a liberal 1/3 maximum output as your average power use you'd still have lots of margin with a 600VA transformer. 500/3 is 167W so even assuming a class AB amplifier with less than 50% efficiency you'd still have lots of room with a 600VA. Even playing loudly enough to drive the amp into regular clipping you won't be using anywhere near the amp's full rated power on an average basis, which is what you need to be concerned with respect to heat and therefore step up transformer rating.

As a footnote, the efficiency of a class AB output stage is actually variable and increases with increasing output power. At full power a class AB amp can be as much as ~70% efficient but might only be 50% at 1/3 maximum output power.

And what dims the lights when you power up big amplifiers isn't only the caps charging (though that's a contributing factor) it's the magnetizing inrush current to the transformer. You'd see that even with an open circuit on the secondary. It's typically worse in toroids than in EI (square) transformers and can be more than 10x the rated current of the transformer primary. Essentially the primary winding acts like a short circuit until the current magnetizes the core. It usually takes a couple of cycles to stabilize. Where in the AC cycle the switch is flipped also makes a difference to the amount of inrush. If it is flipped right at a zero crossing the effect is less than if it is flipped at the peak of the wave. Or is that the other way around? Can't remember.

 

[Mark Reccord]

Incidentally, DC transmission is becoming increasingly common these days. It's a bit different from what Edison was proposing, though. They generate AC as per usual, step it up to transmission voltage and rectify it so it is transmitted as DC. They then use giant inverters to convert back to AC on the load end of the transmission line. This way there are only resistive losses along the transmission line and there's no need for power factor correction like AC transmission lines need because of capacitive and inductive losses. It's also easier to synchronize different power grids together using DC.

 

[agedhorse]

Iirc, inrush current on a transformer is lowest at peak voltage because of the dV/dT minimum. (This is trying to remember something from a class I did not enjoy at all )

 

[CrashClint]

Just buy one of these old Genz Benz Shuttle 6.0, you can find them for around $300 on TB. Just flip the little red switch in the back and forget the transformer. Here is one for $350 with carrying bag. For Sale - Genz Benz Shuttle 6.0 w/carrying case

 

[Old Garage-Bander]

Iirc, inrush current on a transformer is lowest at peak voltage because of the dV/dT minimum. (This is trying to remember something from a class I did not enjoy at all )

So does anyone

Just buy one of these old Genz Benz Shuttle 6.0, you can find them for around $300 on TB. Just flip the little red switch in the back and forget the transformer.

Buying a new amp is a lot more fun than buying a transformer. It weighs less too.

 

[seamonkey]

Get another amp. The transformers are big and heavy. Look for universal power supply that you don't have to switch.

 

[cfsporn]

I did a technology and society course when I did my EE degree and we spent quite a bit of time on the Tesla/Edison/Westinghouse AC vs. DC thing. Until then I didn't really know the history. I had held Edison in pretty high regard until then. Since then, I've become a bit of a Tesla buff. We share a birthday!

But yeah, Edison slandered anyone who went up against him hardcore.



A 600VA transformer is fine for that amp. If you go back and read what @agedhorse posted I think it will make sense as to why. Even if you took a liberal 1/3 maximum output as your average power use you'd still have lots of margin with a 600VA transformer. 500/3 is 167W so even assuming a class AB amplifier with less than 50% efficiency you'd still have lots of room with a 600VA. Even playing loudly enough to drive the amp into regular clipping you won't be using anywhere near the amp's full rated power on an average basis, which is what you need to be concerned with respect to heat and therefore step up transformer rating.

As a footnote, the efficiency of a class AB output stage is actually variable and increases with increasing output power. At full power a class AB amp can be as much as ~70% efficient but might only be 50% at 1/3 maximum output power.

And what dims the lights when you power up big amplifiers isn't only the caps charging (though that's a contributing factor) it's the magnetizing inrush current to the transformer. You'd see that even with an open circuit on the secondary. It's typically worse in toroids than in EI (square) transformers and can be more than 10x the rated current of the transformer primary. Essentially the primary winding acts like a short circuit until the current magnetizes the core. It usually takes a couple of cycles to stabilize. Where in the AC cycle the switch is flipped also makes a difference to the amount of inrush. If it is flipped right at a zero crossing the effect is less than if it is flipped at the peak of the wave. Or is that the other way around? Can't remember.

You share Tesla's birthday too? Nice! We also share it with Dio!

 

[agedhorse]

There are a lot of really nice older amps available used at a bargain, even in the TB classifieds. You might want to take a look and see if something there might be a good fit for your needs.

 

[Mark Reccord]

Iirc, inrush current on a transformer is lowest at peak voltage because of the dV/dT minimum. (This is trying to remember something from a class I did not enjoy at all )

Yeah, now that you said that, I think that's indeed the case. Opposite of what you might think on first glance.

You share Tesla's birthday too? Nice! We also share it with Dio!

Haha, awesome! We totally need a devil horns smiley!