Double Bass Does 1 W class D = 1 W other class amps ?

[Alain Bass]

HI
The question has been asked several times, but I am starting again:
I wonder if 1 W of class D amps is equal to 1 W of others class amps ?
Before I was playing on 200 W amps, today I have almost 600 W, and I don't feel a big difference between the two.
I know the power is exponential, 3 db to double, but …
What do you think:
Is 1 watt of class D amps equal to 1 watt of others class?
Thank's for your answers
Alain

 

[Luigir]

HI
The question has been asked several times, but I am starting again:
I wonder if 1 W of class D amps is equal to 1 W of others class amps ?
Before I was playing on 200 W amps, today I have almost 600 W, and I don't feel a big difference between the two.
I know the power is exponential, 3 db to double, but …
What do you think:
Is 1 watt of class D amps equal to 1 watt of others class?
Thank's for your answers
Alain

Unfortunately Watts are not the right unit of measurement for discussing about perceived volumes. Furthermore, as you've said the logarithmic nature of the game makes quite difficult to think easily about it.

Take a look at this page:
Double amplifier power does not double the volume - Geoff the Grey Geek

At the bottom of the page you'll find a calculator. You'll see that moving from 300W to 500W gives you a mere 17% of perceived loudness gain.

To double the perceived volume you'll need 3000 (three thousand) Watts...

IMHO, I guess that increasing watts, after a certain amount, is mainly a marketing way to let you believe you have more power.

Hope this helps.

P.s. this suggests to take with a grain of scepticism the common statement: "I'll take a 4Ohm cab to use all the power of my amp."

 

[Alain Bass]

Thanks for your answer, I take a look at the page you mentioned, but I could ask my question another way:
Two amps, one class D, the other class (x). Same cab, etc. Does at 50 W for ex. the level of volume (loudness) of the two will be the same?

 

[brianrost]

Before I was playing on 200 W amps, today I have almost 600 W, and I don't feel a big difference between the two.
Is 1 watt of class D amps equal to 1 watt of others class?

A watt is a watt is a watt. Why some amps sound louder or quieter than expected by the wattage rating can be anything from baked in EQ curves emphasizing certain frequencies to volume control taper to the wattage rating being overly optimistic to compression effects when the amp is driven hard to the limiters found in most class D amps.

 

[Black Out Jazz]

Sounds like buyer's remorse. This is beyond speculation without knowing about a hundred other facts. Like what kind of cab, what kind of driver, what is the efficiency of speakers, how is amp EQ-ed, etc. etc. etc.

 

[Alain Bass]

OK, so I asked the question like this: I specified with the same equipment, at the same level of watt, is the level of volume of the two the same or not? Apparently the answer is: 1 watt is 1 watt, which means that in terms of electric power, what is sent to the HP is the same. There are no regrets from me, just when I read for ex. that the TC Bam 200 is a little short in level, I remember my 200 W 360 acoustic with which I never had any level problems.
My question could have been: why today a class D amplifier of 200 W is a bit short in level whereas yesterday we used much less powerful amps and that was enough for us.

 

[two fingers]

HI
The question has been asked several times, but I am starting again:
I wonder if 1 W of class D amps is equal to 1 W of others class amps ?
Before I was playing on 200 W amps, today I have almost 600 W, and I don't feel a big difference between the two.
I know the power is exponential, 3 db to double, but …
What do you think:
Is 1 watt of class D amps equal to 1 watt of others class?
Thank's for your answers
Alain

I think the electronically enlightened among us could give you a much better answer if you just describe the whole rig including both heads. There are myriad factors that go into perceived volume.

One thing I will tell you for sure is that watts have been given WAY too much credit over the years. They are but a part of the equation.

 

[Alain Bass]

Maybe I misspoke, my reflection was that: yesterday, when you bought a 100, 200 W amp, you knew that with that you could do a large venue or have enough power to deal with.
Today, if you want the same thing, you have to think almost 600 W or more. The loudspeakers being always 4 or 8 ohms.
That was just the starting point for my reflection.
So I was wondering if 1W class D = 1 W other class ?

 

[Greg Clinkingbeard]

I’m not an electrical engineer but follow, then agree or disagree.

Power (watt)= voltage x current

Growing up in the 1970s and getting interested in HiFi gear I would read all the magazines. The prevailing wisdom was ‘watts are watts’ and the reviewers would take test measurements of all the gear. Consequently, the ‘best’ receiver or amplifier was the one with the most power and lowest distortion. Spec Wars led buyers to inexpensive receivers that measured well but didn’t sound all that great.

Why then, did one 100 watt amplifier with low distortion sound thin and another 30-40 watt amplifier sound warm and sound fuller in the bass? Usually, the one with a warmer and fuller sound had a larger power supply. It had the ability to deliver more current. Current is necessary for effortless delivery of bass response. There is a reason the top stereo amplifiers weigh over a pound per watt and benefit from dedicated AC circuits.

Comparing a GK 400RB which produces 100 watts into 8 ohms (IIRC) to any class D amp producing say 200 watts will show that the old design will play louder and deliver more low end into the same speaker cabinet. That has been my experience anyway.

That said, the old amps are long gone and I use a TC Bam200 because the convenience wins and it still sounds great.

 

[AGCurry]

... just when I read for ex. that the TC Bam 200 is a little short in level, I remember my 200 W 360 acoustic with which I never had any level problems.
My question could have been: why today a class D amplifier of 200 W is a bit short in level whereas yesterday we used much less powerful amps and that was enough for us.

Yes, a watt is a watt regardless of its source. Volts x Amperes = Watts.

Electrical output of the amplifier is only one factor in perceived loudness. Electrical efficiency of the speaker is just as significant a factor, as is acoustic efficiency (cone area and cabinet design). Your Acoustic 360 probably had a pretty efficient speaker, with more cone area. You haven't yet stated that you're using the same speaker to do your volume comparison, or for that matter, what speaker(s) you're using.

Speakers had to be efficient when output power was expensive. Today, watts are cheap, so speakers can be less efficient.

 

[Alain Bass]

the one with a warmer and fuller sound had a larger power supply. It had the ability to deliver more current.

You 're probably right with the power supply.
Me also I use only Class D amps

 

[Luigir]

OK, so I asked the question like this: I specified with the same equipment, at the same level of watt, is the level of volume of the two the same or not? Apparently the answer is: 1 watt is 1 watt, which means that in terms of electric power, what is sent to the HP is the same. There are no regrets from me, just when I read for ex. that the TC Bam 200 is a little short in level, I remember my 200 W 360 acoustic with which I never had any level problems.
My question could have been: why today a class D amplifier of 200 W is a bit short in level whereas yesterday we used much less powerful amps and that was enough for us.

I see. Maybe it's not class D vs valve but RMS vs MaxPower. Quoting from the manual the TCBam200 is rated for 200 Watts maximum power independent of limiters and driver protection circuits. The actual RMS could be significantly lower (140? Maybe more maybe less).

 

[yodedude2]

So I was wondering if 1W class D = 1 W other class ?

yes.

bear in mind that a 'watt' is a measure of power, not perceived volume.

 

[Alain Bass]

You haven't yet stated that you're using the same speaker to do your volume comparison, or for that matter, what speaker(s) you're using.
Speakers had to be efficient when output power was expensive. Today, watts are cheap, so speakers can be less efficient.

I was speaking in absolute terms without specifying which HP I was using. Let's say with the same rig.
I am not sure that the HP today have a lower Sensitivity than yesterday

 

[Jefenator]

A watt is a watt but rating critera are all over the place. (I noticed this once while trying out car stereos - the 30 watt Blaupunkt clearly blew away the 80 watt Kenwood.)
Sometimes they include distortion specs in the small print. The more generous you are with your tolerance there, the higher a wattage spec you get to claim. But that's just one factor - and half the time they don't even include that.
That's why I'm not a numbers kind of guy; I go more by word of mouth and seat of pants impressions.
My rough layman's take is that there are indeed 3 different perceived volume categories for bass amp wattage ratings: tube, "lead sled" and "micro head".
That's not a knock on the latter at all - just have to understand that 200 watts - or 700 - translates into something very different for each type in terms of practicality and stage presence.

 

[AGCurry]

I was speaking in absolute terms without specifying which HP I was using. Let's say with the same rig.
I am not sure that the HP today have a lower Sensitivity than yesterday

I don't know what you mean by "HP."

@Luigir and @Jefenator point out correctly also that wattage ratings can confound us in that some numbers are RMS (root-mean-square) and some are "peak" or "program."

 

[Luigir]

I'll add just one trivial fact. As mentioned above the TCBAM200 is max power 200W at 4Ohms which, as I've mentioned could be significantly less speaking about RMS.

I haven't found the Acoustic 360 manual but it might have been 200 Watts RMS (and maybe at 8 Ohm). In this case it felt louder simply because it was louder.

Unfortunately, the maxPower indication is certainly true but IMHO it's kinda of a marketing claim and it's not really useful to guess how the amp will behave.

 

[Alain Bass]

I don't know what you mean by "HP."
@Luigir and @Jefenator point out correctly also that wattage ratings can confound us in that some numbers are RMS (root-mean-square) and some are "peak" or "program."

You were talking about my acoustic 360 and saying that I did not specify which HP I was using to compare with my class D amp. So I replied that my comparison has to be made with the same equipment.
Yes your answer between RMS and peak.

 

[Greg Clinkingbeard]

I have no doubt that into the same speaker, the old 400RB would deliver more volume and with a fuller low end than the BAM200. Sure, watts is watts but amplifiers are tested in a laboratory using methodology agreed to by manufacturers and government regulators. Real experience tells the truth, as Alain Bass has experienced.

 

[Alain Bass]

My rough layman's take is that there are indeed 3 different perceived volume categories for bass amp wattage ratings: tube, "lead sled" and "micro head".
That's not a knock on the latter at all - just have to understand that 200 watts - or 700 - translates into something very different for each type in terms of practicality and stage presence.

I believe it is the wisest, indeed.
You can't compare a Class D amp in terms of level with another class.
As you said, for each class, you need to have your own judgment.
I just order a TC Bam 200 for a light rig.
My others amps are: Jay Ganz Straight Ahead Power Head and Focus SA 600 W.