Watts manufacturers doings to us - RMS vs Peak - it’s time to take a stand

[dyerseve]

1 minute ago, chris_b said:

Plainly you are not reading what I'm writing. I'm not bickering with you . Good-bye.

I read what you posted. you stated they were cheating their customers which is exactly what the manufacturer of these amps was doing. Im fairly sure trading standards(a regulatory body) would take issue with the misrepresentation of the amps specifications as well. I am not saying the two cases are identical but the principals are clearly similar.

[grenadillabama]

I would like to see a test where a big 500w or 800w amp were connected to a large 810 : turned up till a clean sound became a bit distorted, then turned down a little until it 'got clean' . Then a mic placed 25' or 50' back would be connected to a recorder with a VU meter ,set to read "0 dB". Then another brand of amp tried (like GK & Ashdown ) to see which was louder with a similar tone. There would be rankings on down to the lousy , crummy amps we all wish to avoid. What do the newest Acoustic amps sold by Guitar Center really put out in clean watts ? They are loud at the store and have pretty blue lights but do I want one. (I like Ashdown best)

[krispn]

The sheer futility of it all. Thanks @Cuzzie you d i c k 😀😂

[Bill Fitzmaurice]

6 hours ago, scalpy said:

I asked Trickfish straight up about their power ratings and they flat refused to give an answer. Similar to a post further up there was the ‘its impossible to qualify and there are so many variables’ argument.

Impossible to qualify? Maybe. Impossible to quantify? Hardly.

Watt, unit of power in the International System of Units (SI) equal to one joule of work performed per second, or to ¹/₇₄₆ horsepower. An equivalent is the power dissipated in an electrical conductor carrying one ampere current between points at one volt potential difference.

Source: Encyclopaedia Britannica

[Phil Starr]

1 hour ago, Bill Fitzmaurice said:

Impossible to qualify? Maybe. Impossible to quantify? Hardly.

Watt, unit of power in the International System of Units (SI) equal to one joule of work performed per second, or to ¹/₇₄₆ horsepower. An equivalent is the power dissipated in an electrical conductor carrying one ampere current between points at one volt potential difference.

Source: Encyclopaedia Britannica

This is completely the point, watts are not subjective random nebulous things. they can be measured there is proof. So if a manufacturer lies there is an objective way of catching them out. Quite rightly there are laws against deliberate deception for financial gain across Europe, America and most of the world. Unfortunately not all our governments support trading standards enforcement as they should but that is down to the demands we put upon them as consumers and voters. Put your hands up those of you who support fraud.

There are minor bickerings of course. An amp may supply 500w but only for a few seconds and another may do so all day, It may supply full power at 1% distortion or 3% distortion and maybe the power is rolled off at 50Hz in one amp and 20Hz in another but all of this is covered in regulations in different countries and only accounts for small variations in rated power. It is also true that few of us use all the power available to us from our amps and 250W is a lot of power which is enough for most of us. It's also true that some people like to play Top Trumps with power ratings. Plenty of people with cars with fourwheel drive and sport settings on their suspension never go near a puddle or racetrack but if they are being charged for something that says it does 0-60 in 5secs or 65mpg it should be able to achieve those claims in verifiable repeatable tests. Why would bass players or musicians exclusively agree to lower standards than the rest of the population.

If an amp manufacturer makes a claim about their amp it should be provable and their responsibility to prove it. If they want to sell an amp with the claim 'loud enough' that's fine, a brave marketing strategy but up to them. The big problem is that if we let a few companies get away with it then others are forced to follow their deciepts or lose customers. It isn't just bass amps of course, we currently allow drugs companies to bury research which does not show the effectiveness of their products or identifies possible side effects. We know that it wasn't just VW who were fiddling their emissions data. Bass amps may be small beer in comparison but it is something we are all competent in and major consumers of. It's kind of important to call out this sort of behaviour as it happens.

I'm perfectly happy for anyone to say a TC amp is loud enough or that the Bugera is great value for money, I can't for the life of me understand why some people are arguing that fraud is a good thing.

 

[BreadBin]

Well said @Phil Starr

[ebozzz]

5 minutes ago, Phil Starr said:

I can't for the life of me understand why some people are arguing that fraud is a good thing.

 

I'm admittedly not a Physics person. Nor am I an engineer. Neither am I of the opinion that "fraud is a good thing". If fraud can be proven by testing the amp, I'm fine with the results of testing. Fine meaning that I can accept it with no qualms. 

Bugera claims 2000 watts peak at 4 ohms. Can that claim clearly be ruled out without testing? 

[Chienmortbb]

On 15/11/2018 at 10:53, mikel said:

I may be miles out here but in the days of all valve amps were we not fairly sure of the power said amps would produce?  Then it was simply down to the number of cabs and speakers to produce the volume needed? As I say I am guessing but I recall most 100w amps back in the day being similar volume wise through say a 4 x 12 cab.

That is because  AFAIK most used standard circuits. Marshall, Sound City et all used the old Mullard amplifier designs manual.

[dyerseve]

On 16/11/2018 at 16:17, ebozzz said:

I'm admittedly not a Physics person. Nor am I an engineer. Neither am I of the opinion that "fraud is a good thing". If fraud can be proven by testing the amp, I'm fine with the results of testing. Fine meaning that I can accept it with no qualms. 

Bugera claims 2000 watts peak at 4 ohms. Can that claim clearly be ruled out without testing? 

It probably could be ruled out without testing simply by looking at the schematics but I dont think anyone here has suggested the claims haven't been tested or that it shouldn't be tested. 

Edited November 17, 2018 by dyerseve

[scalpy]

Apologies for the earlier quotation marks, that was my recollection at being what I felt was fobbed off and in my defence I’d overslept, was late for work and shouldn’t have been posting at all! Here is the actual answer I received:

‘‘We really prefer not to get into those discussions because there are no set standards for how companies come to their RMS ratings and the number Itself doesn’t really mean much on its own. 

We use the ICE 700 power module in the BH.5 and the Pascal SPro2 in the Bullhead 1K and they both have detailed specs online. 

I wish I had a more satisfactory answer for you as I know the RMS value is a popular number to use to compare amplifiers. But unless the number is achieved using identical testing procedure the number really confuses more than helps.’

Still don’t know if their amp would blow my speakers or not be loud enough, even as a ball park- no sale.

[dyerseve]

3 minutes ago, scalpy said:

Apologies for the earlier quotation marks, that was my recollection at being what I felt was fobbed off and in my defence I’d overslept, was late for work and shouldn’t have been posting at all! Here is the actual answer I received:

‘‘We really prefer not to get into those discussions because there are no set standards for how companies come to their RMS ratings and the number Itself doesn’t really mean much on its own. 

We use the ICE 700 power module in the BH.5 and the Pascal SPro2 in the Bullhead 1K and they both have detailed specs online. 

I wish I had a more satisfactory answer for you as I know the RMS value is a popular number to use to compare amplifiers. But unless the number is achieved using identical testing procedure the number really confuses more than helps.’

Still don’t know if their amp would blow my speakers or not be loud enough, even as a ball park- no sale.

Yep that's a proper BS reply and as you say some figure would be better than none. All they have to do is provide the parameters of their tests to produce their claimed RMS figure and they are in the clear.

Telling you what modules they use is not necessarily helpful as(IIRC) it will be how those modules are implemented and what PSU spec/design is powering them that will ultimately determine how much output power they are capable of producing.

[paul_c2]

My reckoning is that the manufacturers know that if they revealed proper specs (first) which conclusively showed they are less power than their similarly-priced competitors, then they'd lose sales off of that. More lost sales, than if they keep quiet and duck questions such as the above.

This is why in other products, for example vacuum cleaners, cars, etc there are more and more legal requirements on displaying the proper specs - for "consumer protection" reasons. I am not sure if we want more regulation on amp sales - maybe it would be a good thing, if it were done properly. I am not that bothered with the actual power rating, so long as its "loud" enough but unfortunately that's something of a mystical figure - I'd not know, even if there were an agreed scale, what number the amp needed to meet/exceed!

[funkydoug]

This has been an interesting read, thanks folks. 

Only half joking with this question... 

Can anyone explain why old Trace Elliott (and maybe a few others like Peavey) are perceptibly louder than most other amps with like for like RMS ratings? People usually just grin and shrug, but is there a reason Trace Watts seemed to be louder?? I ask in sheer curiosity, as a fan of both science and Trace Elliott

 

[Bridgehouse]

2 minutes ago, funkydoug said:

This has been an interesting read, thanks folks. 

Only half joking with this question... 

Can anyone explain why old Trace Elliott (and maybe a few others like Peavey) are perceptibly louder than most other amps with like for like RMS ratings? People usually just grin and shrug, but is there a reason Trace Watts seemed to be louder?? I ask in sheer curiosity, as a fan of both science and Trace Elliott

 

The output from a Trace Amp has special “Trace ooomph” built in, a bit like special sauce

[dyerseve]

37 minutes ago, funkydoug said:

This has been an interesting read, thanks folks. 

Only half joking with this question... 

Can anyone explain why old Trace Elliott (and maybe a few others like Peavey) are perceptibly louder than most other amps with like for like RMS ratings? People usually just grin and shrug, but is there a reason Trace Watts seemed to be louder?? I ask in sheer curiosity, as a fan of both science and Trace Elliott

 

It could well be that those amps you remember as being louder used Class A design where as the others were Class D or another Class altogether. They may have all had the same rating into an 8 Ohm load but if they were all connected to a 4 Ohm load then the Class A amp will be able to "double" it's output into that load where as the others will not. 

Either that or they just had superior power supplies to the other amps again allowing them to more easily drive more difficult loads without clipping/distorting 

I'm not an expert but that is my understanding of It and a possible explanation for your subjective impressions of loudness.

[Bill Fitzmaurice]

43 minutes ago, funkydoug said:

Can anyone explain why old Trace Elliott (and maybe a few others like Peavey) are perceptibly louder than most other amps with like for like RMS ratings? People usually just grin and shrug, but is there a reason Trace Watts seemed to be louder??

Google : 'Gain Staging'. The gain of the pre-amp and how the gain and/or volume controls are configured define how loud an amp will be at given knob settings. It doesn't affect actual output capacity. There are amps that produce full power with the knobs set at 3 or 4, but they don't produce any more power at higher settings. There are amps that are quite linear from zero to 10. In the case of the former some companies did so intentionally so in a music store their amp would be much louder at 3 or 4 than the one next to it, confident that they wouldn't be compared with both set at 8 or more, lest the store owner pull the plug. 

[funkydoug]

Good shout, the power supply that is. 

Don't think it's about Class A and Ohms as these sounded very loud (and still do) in 8ohm combos. 

Could also be something to do with how the volume pots worked. Few people know how much louder they get past about noon! 

 

 

Just seen that Bill has suggested the volume knobs too. Wish I could say great minds think alike... but that'd be doing BFM a disservice  

[dyerseve]

33 minutes ago, funkydoug said:

Good shout, the power supply that is. 

Don't think it's about Class A and Ohms as these sounded very loud (and still do) in 8ohm combos. 

Could also be something to do with how the volume pots worked. Few people know how much louder they get past about noon! 

 

 

Just seen that Bill has suggested the volume knobs too. Wish I could say great minds think alike... but that'd be doing BFM a disservice  

In that case it would more likely be the value of the pot used rather than the type of pot used ie logarithmic rather than linear. 

All volume pots should be logarithmic but the value of pot used could differ providing cause for difference in the actual volume relative to the position of the volume knob AFAIK.

[Mottlefeeder]

2 hours ago, dyerseve said:

In that case it would more likely be the value of the pot used rather than the type of pot used ie logarithmic rather than linear. 

All volume pots should be logarithmic but the value of pot used could differ providing cause for difference in the actual volume relative to the position of the volume knob AFAIK.

Less likely to be the value of the pot, and more likely to be the gains of the circuit blocks before and after the pot. Also, the law of the pot may also be defined by its place in the circuit, e.g. within a feedback loop in designs where there in no separate input gain control.

David

[Mottlefeeder]

4 hours ago, scalpy said:

Apologies for the earlier quotation marks, that was my recollection at being what I felt was fobbed off and in my defence I’d overslept, was late for work and shouldn’t have been posting at all! Here is the actual answer I received:

‘‘We really prefer not to get into those discussions because there are no set standards for how companies come to their RMS ratings and the number Itself doesn’t really mean much on its own. 

We use the ICE 700 power module in the BH.5 and the Pascal SPro2 in the Bullhead 1K and they both have detailed specs online. 

I wish I had a more satisfactory answer for you as I know the RMS value is a popular number to use to compare amplifiers. But unless the number is achieved using identical testing procedure the number really confuses more than helps.’

Still don’t know if their amp would blow my speakers or not be loud enough, even as a ball park- no sale.

I've just been on the Pascal website and checked out the module specified - it claims 1000w RMS into 8 ohms or 4 ohms ( the latter limited by the power supply capability) at 1% distortion.

http://www.pascal-audio.com/product/s-pro2/

On paper that looks good, but if testers cannot get that power out of it that suggests that the gain structure may be wrong.

David

[bumnote]

5 hours ago, Bill Fitzmaurice said:

Google : 'Gain Staging'. The gain of the pre-amp and how the gain and/or volume controls are configured define how loud an amp will be at given knob settings. It doesn't affect actual output capacity. There are amps that produce full power with the knobs set at 3 or 4, but they don't produce any more power at higher settings. There are amps that are quite linear from zero to 10. In the case of the former some companies did so intentionally so in a music store their amp would be much louder at 3 or 4 than the one next to it, confident that they wouldn't be compared with both set at 8 or more, lest the store owner pull the plug. 

When I had my acoustic 450 i used to say to my band mates when they complained about my volume look its only on 1 and a half. I could turn it up to no 8 and it wouldnt get any louder.

[dyerseve]

8 hours ago, Mottlefeeder said:

Less likely to be the value of the pot, and more likely to be the gains of the circuit blocks before and after the pot. Also, the law of the pot may also be defined by its place in the circuit, e.g. within a feedback loop in designs where there in no separate input gain control.

David

Thanks for clearing that up David. As I readily admit I am not an expert so I was merely making a somewhat educated guess. 

[ebozzz]

19 hours ago, dyerseve said:

It probably couldbe ruled out without testing simply by looking at the schematics but I dont think anyone here has suggested the claims haven't been tested it shouldn't be tested. 

Sometimes things drawn up on paper don't work out as well as expected when implemented and occasionally, the results are better than expected. All that I'm saying is that until there's some definitive proof, it's a little premature to accuse an entity of fraud, If there is some definitive proof, I'd love to review it....

[Phil Starr]

23 hours ago, ebozzz said:

I'm admittedly not a Physics person. Nor am I an engineer. Neither am I of the opinion that "fraud is a good thing". If fraud can be proven by testing the amp, I'm fine with the results of testing. Fine meaning that I can accept it with no qualms. 

Bugera claims 2000 watts peak at 4 ohms. Can that claim clearly be ruled out without testing? 

OK then that explains perhaps why you have concerns and why those of us who have dealt with these issues over a number of years are so frustrated with you. It's a simple matter of misunderstanding.

Measuring an amplifier's output is basically very simple. You connect it to a big resistor of 4ohms (say) put a signal into it and increase the signal until it starts to distort. At that point you measure the voltage the amp can do without distortion (less than 1% is the usual measure) and then the power is voltage squared divided by the resistance. Conventionally this is measured over the whole range of our hearing 20-20,000Hz. It's slightly more complex for a class D amplifier as this operates on high frequency pulses all at the same voltage but passing it through a low pass filter makes comparable measurement possible.

In the US there is long standing Federal legislation to stop misleading claims by advertisers and in Europe various standards exist with the DIN standard widely known. https://en.wikipedia.org/wiki/Audio_power There's some good links at the bottom of the article if you are interested.

You simply cannot design an amplifier without knowing all of the parameters and indeed specifying all the parameters of you amps so the claim of 'we don't know the rms power' or 'we don't calculate it that way' isn't credible.

Another factor is the input power, an amp cannot put more power into the speaker than it takes from the mains. In fact it will lose power both in it's power supply and in the amplifier itself. A class D design with a switch mode power supply is likely to be somewhere in the 80% efficiency range, so if the amplifier has indeed an input rating of 880W then it can only put out 700W. Then there is the long history of Behringer over claiming power outputs in their advertising. For example I own an old Behringer EP2400 PA amp, claimed output 2400W. When you delve into the manual as I did before I bought the amp I found it would produce 285W continuous into 8ohms with both channels driven. I was using 300W speakers at the time so it was an ideal match and a lot of bang for the buck so a good buy. The over -claiming was irritating but I'm a scientist and the data was all available. With the Beyron it isn't and Behringer are no longer publishing all the data on a lot of their gear. I think it's pretty stupid really as a 500W amp at this price is still beating the whole market and false advertising just makes the company look suspect and contemptuous of their customers.

As a 'Physics person' I come on here to repay all those who have helped me with my bass playing by advising them as best I can on technical stuff. I'm still enough of an old hippy to see the people here as friends and I don't want them conned. If someone delivered a Beyron to me it wouldn't be difficult to test it but I know more than enough to know that it makes way less than 2000W. If it is part of the decision of what to buy then I want people here to know what is true and what is incredible.

[Skybone]

On ‎16‎/‎11‎/‎2018 at 07:35, Cuzzie said:

@Skybone is willy wanging different to welly wanging

Yes...

In a Welly Wanging contest, no one boasts about having the biggest wellies do they?