Watts; the worst measurement unit ever for amp output?

[fdeck]

Watts = volts x amps, it a simple measurement of electricity.

That's well and good, but there is more to how amp power ratings are derived.

Watts also equal torque x angular velocity.

 

[1958Bassman]

I hope so. If he gets up and walks away, I'm moving to the freaking Moon.

 

[1958Bassman]

Watts are fine, easy to calculate for complex loads and non-sinusoidal signals. I share the OP's frustration with MI power amp ratings though. It may well be that the Eden was delivering its advertised power. The boogie on the other hand was delivering - well, a whole lot more.

But this brings us to the same problem with car stereo, home theater and stereo amps- the methods of measurement are "standardized", but those standards are as useful as t*ts on a bull. Rating an amp's power output at 1KHz when it's used for full-range sound is absolutely ridiculous. This is probably where MI amps run off the tracks- one may be rated at 50W, 1% THD+noise, 20Hz-20KHz +/-.5dB and another might be rated at 80W, 1% THD+noise, 1KHz and it sounds like a transistor radio with dying batteries. No balls, at all.

 

[1958Bassman]

Maybe it would help to have a calibrated "standard" speaker to run the spl tests with. After all a calibrated (to some standard) microphone is an essential part of all spl measuring devices.

Personally, I always think the answer is try it and use what ever works for you. The amps I was able to try first seemed to stay in my stable a lot longer than the ones I bought (on the internet) based on manufacturer's spec, advertising hype, or flavor of the month; those were flipped pretty quickly.
It seems like my tastes in my bass tones rarely match the "norm" (whatever that is).

Why rate it with one speaker if there's no way to convert the results, so it would be possible to choose a different speaker AND know what the results will be? Why do so many other speakers exist, anyway?

 

[1958Bassman]

That's well and good, but there is more to how amp power ratings are derived.

Watts also equal torque x angular velocity.

Since heat dissipation was mentioned, should we get into the conversion of Watts to BTU or horsepower?

 

[SactoBass]

I currently own two amplifier heads; The first one is an Eden WTX 264. The other is a Mesa boogie 400+.
Both of these heads are rated at extremely similar power output into 4 ohms. Between 264 and 275 W.

Using the same cabinet, a Schroeder BMF 212, the Eden's maxed out i.e. will begin to distort unpleasantly with all my knobs at about 2 oclock with the bass boost pulled out and the mid shift pulled, utilizing every single bell and whistle, I can barely play bass in my band to a medium-size room.

With the Mesa boogie into the same 4 ohm cabinet, master at three volume three I never ever ever can crank the controls on the same bass past halfway and I'm already too loud for the same room!

Watts mean nothing!! Thoughts?

Nukes: what you are experiencing is the simple fact that all-tube amps always crush solid state amps. Period. End of story. Case closed.

You can ignore all of the talk about joules and horsepower and volts and watts and specs and ratings and this and that and the other thing.

Flame suit is on.

(GAWD I love Talkbass! It allows me to make bold statements as if I'm some kind of expert or something!)

Hey! It's Friday night! Smile and have some fun!

 

[JansenW]

Not all amps have the same input sensitivity.

If one amp needs 1v input to produce 500W and another only needs 0.5v input to produce 500W, guess which one will produce more power with 0.5v input?

 

[acmebass]

If you dial the tube amp back to completely clean it will make similar loudness with similar RMS voltage as the SS amp. James Watt can rest easy.

I was about to mention that the signal-to-noise ratio of this thread had gotten extremely low, and that nobody had come close to addressing the OP's question, when, as usual, DUW sort of nails it.

A tube amp will always seem more powerful than a solid state amp of the same power rating because of the soft clip characteristic. I think that's all the OP is experiencing.

The thread itself has been all over the map addressing almost everything else. Interesting. Some right, some wrong, but nearly all irrelevant.

I haven't seen the rest of the thread yet, so other posters might have already gone there without my knowledge, but that's my two cents worth.

It has nothing to do with watts, except peripherally.

Andy

 

[acmebass]

I am undecided if this thread even warrants a response.

Yeah, I was struggling with that, too.

A

 

[acmebass]

Nukes: what you are experiencing is the simple fact that all-tube amps always crush solid state amps. Period. End of story. Case closed.

You can ignore all of the talk about joules and horsepower and volts and watts and specs and ratings and this and that and the other thing.

Flame suit is on.

(GAWD I love Talkbass! It allows me to make bold statements as if I'm some kind of expert or something!)

Hey! It's Friday night! Smile and have some fun!

I wouldn't have put it quite like that, but yeah, pretty much!

Andy

 

[megafiddle]

It has nothing to do with watts, except peripherally.

It has everything to do with watts.
Actual watts though, not published watts.

.

 

[B-string]

Yeah, I was struggling with that, too.

A

Do we dedicate pages upon pages trying to teach why this fatally flawed experiment holds no truth? Why? "The toobs are betterer man period!" will never be persuaded.

 

[acmebass]

It has everything to do with watts.
Actual watts though, not published watts.

.

That's a different question, dude. If one of the manufacturers is misrepresenting his product, that's relevant, of course, but any such accusations ought to be substantiated with data.

Again, I believe this is a solid state/tube issue.

A

 

[acmebass]

Do we dedicate pages upon pages trying to teach why this fatally flawed experiment holds no truth? Why? "The toobs are betterer man period!" will never be persuaded.

Yeah, I've noticed that there are a lot of posters on TB who tend to be very invested in a dogma du jour, and are not particularly interested in data which would tend to contradict their firmly held beliefs.

This is not a phenomenon specific to Talkbass, of course, but to the internet in general!

Andy

 

[SactoBass]

Yeah, I've noticed that there are a lot of posters on TB who tend to be very invested in a dogma du jour, and are not particularly interested in data which would tend to contradict their firmly held beliefs.

This is not a phenomenon specific to Talkbass, of course, but to the internet in general!

Andy

+1

...and I would add "and to life in general".

For the record, I don't actually hold the opinion or belief that one form of amp topology is "better" than the other (whatever "better" means). I just have fun with it. It's a form of entertainment for me, as is nearly everything I encounter on this planet. Actually, I find the entire human race entertaining!

 

[danielfnj96]

Just another thing to think about.. Watts for amplifiers are figured as DC watts into a fixed resistive load. They are not computed into a reactive load such as a speaker. What I am trying to get at is if you measured the DC resistance of your 8 OHM speaker it would measure (I think) 5.73 ohms. The actual reactive impedance is 8 OHMS which varies as frequency changes. I would think that when certain amps are plugged into a speaker they don't perform at the power they were originally spec'd at due to the nature of the reactive load (speaker) ... also some companies spec their amps at 5 or 10 percent THD (as previously mentioned) so you need to look at all of this to get an accurate assessment of power. I used to calibrate power amps and rf amps and they all calibrated using a resistive load.. We used to call it specsmanship by all the amp companies.!!

When i tested my 4 ohm cab with my multi meter it read 4 ohms and when i tested my 16 ohm cab it read 16 ohms so either your tester isn't working or your wrong. Now i'm not saying that your impedance can't be a dependent variable based upon other factors but i am saying your statement about cab resistance is incorrect.

 

[Downunderwonder]

You've got some odd speakers there pal. Actually it's you needing to learn about speaker impedance varying with frequency and the cabinet design.

 

[nukes_da_bass]

But this brings us to the same problem with car stereo, home theater and stereo amps- the methods of measurement are "standardized", but those standards are as useful as t*ts on a bull. Rating an amp's power output at 1KHz when it's used for full-range sound is absolutely ridiculous. This is probably where MI amps run off the tracks- one may be rated at 50W, 1% THD+noise, 20Hz-20KHz +/-.5dB and another might be rated at 80W, 1% THD+noise, 1KHz and it sounds like a transistor radio with dying batteries. No balls, at all.

Balls!
THIS is a quantifiable (yet subjective) concept!
"We here at Excelsior Bass Amplification believe, although not quantifiable, that our bass amplifiers simply have enough BALLS engineered into our units to stop a buffalo stampede or, cut through a Keith Moon/John Bonham double drum solo!".

I mean, since they bend stats to the point of ridicule, why not?

 

[i_got_a_mohawk]

When i tested my 4 ohm cab with my multi meter it read 4 ohms and when i tested my 16 ohm cab it read 16 ohms so either your tester isn't working or your wrong. Now i'm not saying that your impedance can't be a dependent variable based upon other factors but i am saying your statement about cab resistance is incorrect.

Nothing wrong with his meter or speakers. Don't think I've ever seen the measured DCR of a speaker matching the stated impedance, which is a nominal reading.

The impedance varies quite a lot over the frequency spectrum and the stated impedance doesn't mean it's the unplugged DCR.

 

[i_got_a_mohawk]

Balls!
THIS is a quantifiable (yet subjective) concept!
"We here at Excelsior Bass Amplification believe, although not quantifiable, that our bass amplifiers simply have enough BALLS engineered into our units to stop a buffalo stampede or, cut through a Keith Moon/John Bonham double drum solo!".

I mean, since they bend stats to the point of ridicule, why not?

Could always do what some really iffy companies do and market the amplifier by it's draw!