Music in my boat

philwsailz · Feb 25, 2016

Jackdaw said:
I'm not sure I do. What you drew is simply not true for consumers and therefore misleading. I'd be interested in seeing a consumer HiFi stereo amp that has a THD/power relationship like the one you drew. My experience says they look like the actual plot you posted later, or like the one below. Basically flat until you hit rated power, then through the roof.

As I read your response I realize I have done a poor job of communicating the larger underlying points. I agree that good solid state gear has flatter curves. I apologize for using the same scale for both hand-drawn charts. I DID state clearly that the Y-Axis value was completely arbitrary though!!!

Still, I failed to close the loop. Nick suggested his old tube amp rated at X-watts performed like it had more than advertised. Prior discussions had centered on "marketing" specs as well. The take away does not come from scrutinizing the two charts, quickly drawn from memory in MS PAINT. They are simple examples that generally explain the typical curve shape for the two different amp types. Your image conforms, as its lowest distortion is right there close to rated power, just as shared. The difference is the y-axis scale, I know. The point was not to prove one better than the other, just to simply in general speak to the differences.

The takeaway in context to the rest of the discussion is this:
1) Even with HiFi gear, the consumer makes a judgement based on data that does not reflect real-world listening. THD +N is stated at RATED POWER, not normal listening levels.
2) For a HiFi solid state amp, its lowest point of distortion is at full rated power and at lower power levels, i.e. normal listening levels, the distortion is higher. We both will agree it is not much higher, and in fact pretty low. The key point is that advertised specs state distortion at its lowest which is not normal listening level. Remember we started this discussion with the BS "Peak Power" discussion...
3) A clipped solid state amp has a non-musical odd-order harmonic component that is to be subjective, non-musical.

4) Any tube amp, new or used, tested to the same CEA spec will have its distortion measured at rated power. as a result the result will be a distortion number that is higher than what one would experience at normal listening levels.
5) At normal listening levels the consumer will experience lower distortion than the spec suggests.
6) a clipped tube amp has even-order harmonics that are not as offensive to the human ear.

I think this last point might in large part contribute to Nick's statement that his relatively small tube amps seemed like they had more power. Surely you agree with these points?

We could go WAY in the weeds on this, but its not necessary as I don't disagree with you. I think this all comes down to my arbitrary assignment of 10% on the Y-axis, which seems to be the only thing at issue. In hindsight, it would be more fair to have two charts that had two different %THD values along the Y-axis... Sorry for the confusion...

Jackdaw · Feb 25, 2016

philwsailz said:
As I read your response I realize I have done a poor job of communicating the larger underlying points. I agree that good solid state gear has flatter curves. I apologize for using the same scale for both hand-drawn charts. I DID state clearly that the Y-Axis value was completely arbitrary though!!! Still, I failed to close the loop. Nick suggested his old tube amp rated at X-watts performed like it had more than advertised. Prior discussions had centered on "marketing" specs as well. The take away does not come from scrutinizing the two charts, quickly drawn from memory in MS PAINT. They are simple examples that generally explain the typical curve shape for the two different amp types. Your image conforms, as its lowest distortion is right there close to rated power, just as shared. The difference is the y-axis scale, I know. The point was not to prove one better than the other, just to simply in general speak to the differences.

The takeaway in context to the rest of the discussion is this:
1) Even with HiFi gear, the consumer makes a judgement based on data that does not reflect real-world listening. THD +N is stated at RATED POWER, not normal listening levels.
2) For a HiFi solid state amp, its lowest point of distortion is at full rated power and at lower power levels, i.e. normal listening levels, the distortion is higher. We both will agree it is not much higher, and in fact pretty low. The key point is that advertised specs state distortion at its lowest which is not normal listening level. Remember we started this discussion with the BS "Peak Power" discussion...
3) A clipped solid state amp has a non-musical odd-order harmonic component that is to be subjective, non-musical.

4) Any tube amp, new or used, tested to the same CEA spec will have its distortion measured at rated power. as a result the result will be a distortion number that is higher than what one would experience at normal listening levels.
5) At normal listening levels the consumer will experience lower distortion than the spec suggests.
6) a clipped tube amp has even-order harmonics that are not as offensive to the human ear.

I think this last point might in large part contribute to Nick's statement that his relatively small tube amps seemed like they had more power. Surely you agree with these points?

We could go WAY in the weeds on this, but its not necessary as I don't disagree with you. I think this all comes down to my arbitrary assignment of 10% on the Y-axis, which seems to be the only thing at issue. In hindsight, it would be more fair to have two charts that had two different %THD values along the Y-axis... Sorry for the confusion...

Now we're totally on the same page! ;^)

JohnVTX · Feb 25, 2016

Good Grief to all this. I bought a great sounding Pioneer from Walmart........

walt · Feb 25, 2016

I agree John.. my standard ol car stereo in my boat sounds really good to me.

Not that it matters in the slightest (I will never own a tube amp - especially on a boat LOL) but I am curious about this ..

6) a clipped tube amp has even-order harmonics that are not as offensive to the human ear.

This really needs a reference link..

Normal amplitude clipping that begins to turn a sin wave into a square wave produces both odd and even harmonics
https://en.wikipedia.org/wiki/Square_wave.

Jackdaw · Feb 25, 2016

walt said:
I agree John.. my standard ol car stereo in my boat sounds really good to me.

Not that it matters in the slightest (I will never own a tube amp - especially on a boat LOL) but I am curious about this .. This really needs a reference link..

Normal amplitude clipping that begins to turn a sin wave into a square wave produces both odd and even harmonics
https://en.wikipedia.org/wiki/Square_wave.

To me this is mostly true as it combines two points:

1) tube amp distortion is mostly harmonic.

2) tube amps typically 'roll' their clipped waves, as opposed to SS amps which clip them squarely.

The square clips are hard on both the ear and the gear!

philwsailz · Feb 25, 2016

you guys are reading WAY too much into this....

Nobody is advocating tubes on a boat. Wait, there are inner-tubes, yuk yuk yuk...
its just a bunch of bored sailors bench-racing because for most of us the water is too cold or hard to actually be on our boats... So we like discussing audio....

Here lets hijack it for a minute. Cetol or Epiphanes...... 5200 or Life Caulk..... vinyl or epoxy........

kloudie1 · Feb 25, 2016

HEY ! We used to work on tube amps on a boat... errr .. maybe it was more like a ship..
When I went to electrical/electronics schools in the Navy back in 1968, our group was fortunate to learn both tubes and solid state (discrete components) .. Now, very little is discrete component stuff (fortunately!) and is gagillions more reliable!... Something like what I worked on would deplete my batteries in less than an hour! Still amazes me when I turn on the Garmin chart-plotter and see what it does for such a small power draw. I don't use 5200 on that chartplotter, Phil !

walt · Feb 25, 2016

1) tube amp distortion is mostly harmonic.

2) tube amps typically 'roll' their clipped waves, as opposed to SS amps which clip them squarely.

The square clips are hard on both the ear and the gear!

Man.. do we ever need a link here showing some actual data.. "rounded clipping".. that must have been a term discussed in marketing school vs engineering school.. The two types of amplifiers do likely have slightly different harmonics when clipping but I bet its very subtle. Anyhow.. without some spectrum analyzer plots.. its more marketing... but it is somewhat interesting to hear what marketing has come up with for the difference. There must be some actual data??

By the way.. in case someone says we need to sail more (or get a life..), I AM going sailing today.

Daveinet · Feb 25, 2016

Something to point out, because of the nature of tube amp distortion being theoretically pleasing up to a point, those added harmonics actually translate into more energy and a fatter sound. As a result, those added harmonics give the perception that the tube amp is louder because the sound is artificially more full. It's not accurate, but is somewhat pleasing to those who are used to it. I will state that being young enough to grow up on mostly solid state, I much prefer the cleanliness of solid state that some will refer to as sterile. If the sound is too thick, the details are lost in those added harmonics, particularly in the low mid-range. Much of it is what you have learned to like. I will always remember back in the day, listening to these mega dollar turn tables at the CES shows. Their marketing gurus would talk about how wonderful it sounded, but for me, I could not get past the IM distortion introduced by the needle scratching against the vinyl.
To come around full circle, the listening environment is way to compromised in your boat or your car for any of this to matter. A reasonable set of efficient speakers, and a decent amp is really all one needs. Most of the time, the source material will not be serious enough for it to matter. Half the time, we use our cell phones as a music source.

BTY: Walt, that rounded clipping refers to the wave form, and is technically correct. In a solid state amp, when it clips, the transistor just runs out of voltage, and you end up with a very sharp corner, as you loose the rounded top of the sine wave. That sharp corner by definition is a lot of high frequency content, which tends to take out tweeters pretty quick. As you approach clipping, the sound becomes very brittle because of those artificial high frequencies. In a tube amp, the output stage is a transformer, that has inductive properties and limited frequency response. Those inductive characteristics round off that waveform, as the magnetics "coast" in the same direction that were previously going. One can think of trying to draw a sinewave on paper with a big spring between your hand and a very heavy pencil. To some extent, the end result is what the output of a tube amp looks like.

walt · Feb 25, 2016

Tubes.. I turn 60 in 5 days, started engineering school in 1975 and this is mostly what I remember about tubes (on topic as you can see boats in the background)..

justsomeguy · Feb 25, 2016

Daveinet said:
Most of the time, the source material will not be serious enough for it to matter.

Way true. Way, way true.

Jackdaw · Feb 25, 2016

walt said:
Man.. do we ever need a link here showing some actual data.. "rounded clipping".. that must have been a term discussed in marketing school vs engineering school.. The two types of amplifiers do likely have slightly different harmonics when clipping but I bet its very subtle. Anyhow.. without some spectrum analyzer plots.. its more marketing... but it is somewhat interesting to hear what marketing has come up with for the difference. There must be some actual data??

Rounded clipping waveform. Voltage over time. McIntosh MC240 tube amp. Happy?? ;^)

Meriachee · Feb 25, 2016

Jackdaw said:
Happy

Never.
1. Everything louder than everything else.
2. Output from the rig, solely based on the ability to keep the fans from shutting the stacks down.
The two guiding principles for the club sound guy.

walt · Feb 25, 2016

Happy??

I will be later today when Im pulling out of the marina.

Two things about that.. you could have a solid state amplifier show a waveform like that simply by band limiting. For example, if whatever signal that goes to the speakers is rolled off at just past 20 Khz, you will never see a square pulse - because the harmonics to produce a square pulse essentially go to infinity. Every amplifer setup (tube or solid state) is band limited and there is no reason for them not to be since we cant hear above some range. Also, at that level of clipping (like in that waveform), everyone would be able to hear it and think it sounded awful, not sure it matters.

FYI, the way to generate ODD harmonics ONLY is with a triangle wave. Solid state amps dont distort this way.

Brian S · Feb 25, 2016

Meriachee said:
Never.
1. Everything louder than everything else.
2. Output from the rig, solely based on the ability to keep the fans from shutting the stacks down.
The two guiding principles for the club sound guy.

Now I know why I hate the club sound guy! No wonder it sounds like crap in there! Thank god for my earplugs

Meriachee · Feb 25, 2016

Nah, the owner one night said that he turned to the guy next to him and wound up screaming to be heard and that he never realized just how loud it was. Loud, yes, clean, always.

Brian S · Feb 25, 2016

I started wrecking my ears as a kid, blasting stacks of "caps" with a rock. Then I did further damage in my early 20's going to concerts and a lot of clubs. I started putting cotton in my ears, and then later said "What the heck? Who cares!" and started using foamy ear plugs. Now, I don't care what concert or club, I still use ear plugs.

Even a guy sitting in a bar with a guitar has to amplify himself too loud for me to enjoy my companion's conversation. If I see a band setting up in the room, I make darn sure I finish up my meal and get out (unless I know they are a good band - not too likely for me anymore...)

Hey, you kids stay outta my yard!

(My best friend has started calling me "Mr. Grumpalumpagous" from time to time

)

Brian S · Feb 25, 2016

Hey, Jackdaw and Philwsailz: Care to weigh in on those multi-thousand dollar power cords for amps that the "audiophiles" SWEAR makes their amps sound better?

I think I remember a blind A/B test between said super fancy power cords and coat hanger wire, where no one could tell the difference.

Meriachee · Feb 25, 2016

Not unlike the $4.99 hdmi cables we got at the dollar store. 4k video looks just fine.