Why are separates so much more expensive?

[TLS Guy]

Well I guess its a race between the amp's fuse and the speaker coil. If the transistor is shorted circuited, it would mean that the rail and ground are connected together shorting out even the speaker terminals. I guess I would need to see the schematic of the output side to be accurate about this.

Yes, it shorts through the speaker. The rail voltage goes right through the collector to emitter. The amp line fuse will blow, but unless the woofer is very robust damage is done. 90 to 110 Volts DC really heats the coil in a hurry, and often pushes the voice coil out of the gap.

I have to say, that apart from the early seventies, I have not personally come across a direct coupled amp that did not have speaker protection. That Mondial Accurus is an unusual encounter.

 

[AcuDefTechGuy]

Yes, it shorts through the speaker. The rail voltage goes right through the collector to emitter. The amp line fuse will blow, but unless the woofer is very robust damage is done. 90 to 110 Volts DC really heats the coil in a hurry, and often pushes the voice coil out of the gap.

I have to say, that apart from the early seventies, I have not personally come across a direct coupled amp that did not have speaker protection. That Mondial Accurus is an unusual encounter.

What about Emotiva and Outlaw Audio amps? Do they have excellent speaker protection?

 

[TLS Guy]

What about Emotiva and Outlaw Audio amps? Do they have excellent speaker protection?

The answer is yes to both. Emotiva states so on their site. Outlaw are very forthcoming, and state their protection is by opto couplers. That will be one of those opto MOSFET circuits that I previously sent you. So in terms of protection Outlaw are very up to date.

Really a manufacturer has to protect the customers speakers from DC at the speaker terminals. This is now such a well known problem, that it is established that if an amp fries speakers due to DC at the speaker terminals, then the manufacturer of the amp has to replace the customer's speaker. The protection circuits add minimal cost, so no reputable manufacturer is going to leave it out. If they do leave it out, I mark them a sloppy, and would have reservations about everything else in the circuit.

Remember Klipsch bought Mondial because they were in trouble, and dropped the line like a hot potato. I wonder why?

 

[ZoFo]

Why Separates are better than AVR's

How about it just a hell of a lot more fun playing / experimenting with separates then avr's? There is a place for both, I would not want a large rack on an offshore fishing boat full of separates, although Parasound has addressed this issue pretty well. Don’t want a rack full of separates in the fishing cabin for drunk fishermen to screw up nor expose them and their external connections to the salt air, a $350 AVR works nice here. But there is nothing like having a couple of racks of components you have collected over the years if you are a person that likes to tinker and who is interested in electronics themselves, not just the music it produces. I am an electronics junkie, it’s just one of my hobbies.



You can get a Emotiva combo for around 2K that all but Flagship Receivers cannot touch; at least none I have ever seen, and better & more powerful processors are usually found in separates and they DO process the Dolby / DTS sound tracks much better then your average mid-range Receiver. I am not going to get into why or even say I can "prove" it, but I notice a huge difference between the two and I am no Golden Ear.

No separates are going to touch a $5,000 Dennon AVR for “features”, but very few people need or take advantage of these advanced features, a niche market.

 

[highfihoney]

You ask for information from me to support my claim but in your previous post you submit none,same with this post,zero info to back up your claims

Your math is wrong.

15 Amp service = 1,800 watts X amplifier efficiency = max wattage .
20 Amp service = 2,400 watts X amplifier efficiency = max wattage .

Assuming 40% efficiency from the amplifier, which is on the low end of efficiency, a standard 15 amp service will be capable of running 800 watts,a 20 amp service would be able to produce 960 watts in an amplifier that is 40%efficient,these figures represent a single channel not stereo.

As for not ever seeing or hearing speakers that will take a full 200 watts there are none ive ever seen that will take it but we both know there are a ton of speakers that will use a full 200 watts,with the majority of wattage being converted into motion & heat.

I showed you mine now show me yours.

Still waiting for you (fmw) to show me how a 20 amp line is not enough for a 200watt amp.

 

[PENG]

Still waiting for you (fmw) to show me how a 20 amp line is not enough for a 200watt amp.

Just guessing, may be he meant a 200WX7 amp with all channel at maximum output.

 

[cbraver]

I consider myself a novice, but I have a few questions stemming from this thread maybe someone could answer for me:


1. If we really don't need as much power as we think, why do nightclubs use arrays of high-power amplifiers to get their systems to go that loud? Even if they run special electric, by a lot of the logic used here wouldn't they have run out pretty quick with all those thousand watt plus amps huffin? Not to mention all the huge amp racks I've seen run off standard 20A circuits across my campus without issue. Why do companies like Crown recommend such large amounts of power?
http://www.crownaudio.com/amp_htm/amp_info/how_much_power.htm


Also, check this out from them:
http://www.crownaudio.com/pdf/amps/137331.pdf

Even though that "tech" article has way too much marketing in it, can anyone expand on what they are saying? How does an amplifier designer make packages that are efficient enough to put a lot of power to our speakers on standard circuits?


2. I had a Pioneer Elite receiver powering a pair of Dynaudio 70s with 150 watt per channel. They sounded like they had a blanket over them, compared to what they sound like now powered by a 900W 2 channel Crown amplifier. It was a night and day difference. I'm amazed, and the amp wasn't expensive, it was like $400 bucks MSRP, but only 300 and change after I got done with a rebate and a discount from the store. Maybe I'm crazy, but my speakers seemed to really like this power, and the difference is not subtle. If I'm really only using small amounts of power, why does it sound so different? Why do my speakers sound alive? Why do they go so much louder without feeling like they are "stressing?" Is the pairing just better? Am I just crazy?!


I tried to not make this post come off as leaning toward one side or the other on this issue, because I honestly don't know... but, any help clarifying this would be helpful... and I think would do more to answer what the original thread was about. Also, sorry if this post sounds like a Crown advertisement, it's not my intention, but rather what I know and they have a nice knowledge base.

 

[WmAx]

2. I had a Pioneer Elite receiver powering a pair of Dynaudio 70s with 150 watt per channel. They sounded like they had a blanket over them, compared to what they sound like now powered by a 900W 2 channel Crown amplifier. It was a night and day difference.

Let's review 3 possible options...

(1) Your imagination at play/placebo.

(2) The Dynaudio speakers have some very demanding current/electrical phase issues that the receiver was not designed to handle, thus causing audible levels of clipping when using the receiver.

(3) You listen at extreme SPLs using dynamic music, and/or have extended listening distance(s) and/or low efficiency speakers requiring far more power than the average person.

(4) Any combination of the previous 3.

-Chris

 

[TLS Guy]

Let's review 3 possible options...

(1) Your imagination at play/placebo.

(2) The Dynaudio speakers have some very demanding current/electrical phase issues that the receiver was not designed to handle, thus causing audible levels of clipping when using the receiver.

(3) You listen at extreme SPLs using dynamic music, and/or have extended listening distance(s) and/or low efficiency speakers requiring far more power than the average person.

(4) Any combination of the previous 3.

-Chris

Chris, I'm very familiar with Dynaudio 17W-75 drivers in all of their guises. However you put two of those together you will have a difficult load to drive. They are not that efficient, and the impedance and characteristics are such they really do require high current delivery. I can accept that they would not be good performers with a receiver.

 

[TLS Guy]

I consider myself a novice, but I have a few questions stemming from this thread maybe someone could answer for me:


1. If we really don't need as much power as we think, why do nightclubs use arrays of high-power amplifiers to get their systems to go that loud? Even if they run special electric, by a lot of the logic used here wouldn't they have run out pretty quick with all those thousand watt plus amps huffin? Not to mention all the huge amp racks I've seen run off standard 20A circuits across my campus without issue. Why do companies like Crown recommend such large amounts of power?
http://www.crownaudio.com/amp_htm/amp_info/how_much_power.htm

As has explained before the db scale is a log scale. So if you have 100 watts per channel, to have it twice as loud you need 1000 watts per channel, assuming the speakers are the same, and they speakers don't exhibit thermal compression, which they probably will. Quite likely they will burn up. Classical music in particular requires large power reserves, because the dynamic range is so wide.

 

[sparky77]

OK, to make you all happy, here's the math on a 20 amp circuit.

20amps x 120volts = 2400va (watts) x .85 (maximum sustained current draw on a circuit per NEC) = 2040 watts x .60 (60% efficiency of average a/b class amp) = 1224 spontanious current draws without negligeable effects on the circuit can be 3 times the continuous draw limit = 3672 watts peak power output.

Any arguements on the math please let me know!

 

[WmAx]

As has explained before the db scale is a log scale. So if you have 100 watts per channel, to have it twice as loud you need 1000 watts per channel, assuming the speakers are the same, and they speakers don't exhibit thermal compression, which they probably will. Quite likely they will burn up. Classical music in particular requires large power reserves, because the dynamic range is so wide.

Well, true double SPL is 6dB increase, which would require roughly 4x the power. There is some variation as to the perceptual matters, where both 6dB and 10dB has been quoted(roughly 10x power) to be perceived as double the loudness/SPL. However, I have noticed that 6dB always sounds like 2x the SPL to me, personally. I have never actually read the conditions and test results from the original perceptual research upon this subject that quoted 10dB, oddly enough.

-Chris

 

[TLS Guy]

Well, true double SPL is 6dB increase, which would require roughly 4x the power. There is some variation as to the perceptual matters, where both 6dB and 10dB has been quoted(roughly 10x power) to be perceived as double the loudness/SPL. However, I have noticed that 6dB always sounds like 2x the SPL to me, personally. I have never actually read the conditions and test results from the original perceptual research upon this subject that quoted 10dB, oddly enough.

-Chris

This work was done back in the twenties and thirties for testing hearing. If you double the amplitude of a signal that is a 6db increase. However add two sounds of equal intensity, such as two speakers then the increase is 3db.

Now the db scale was developed with a reference tone of 1000 Hz. The ear however is maximally sensitive to changes in spl at 4 Khz. The most sensitive band is 1 to 5 KHz. The ear is much less sensitive at lower frequencies, were spl has to be increased by more than 10db to create a perception of doubled loudness.

 

[WmAx]

This work was done back in the twenties and thirties for testing hearing.

Yes, I do know the general date of the research. Do you have the actual original journal articles? I have never seen these.

If you double the amplitude of a signal that is a 6db increase. However add two sounds of equal intensity, such as two speakers then the increase is 3db.

You should be more specific for readers here. If you combine two sounds of equal intensity, and they are non-coherant(that is, not in identical phase, at least within a few degrees of each other), then summing the two will have a 3dB increase in SPL. If, however, the two sources are coherent, then there will be a 6dB increase in SPL(for example, two identical subwoofers sitting next to each other).

Now the db scale was developed with a reference tone of 1000 Hz. The ear however is maximally sensitive to changes in spl at 4 Khz. The most sensitive band is 1 to 5 KHz. The ear is much less sensitive at lower frequencies, were spl has to be increased by more than 10db to create a perception of doubled loudness.

I am very familiar with the equal loudness contour charts/research. But I must say, 6dB increase, overall, sounds like 2x the loudness to me in virtually every circumstance. This is why I want to read the full original research articles: to understand the precise conditions under which these tests were performed, as well as to review the statistical data acquired.

-Chris

 

[TLS Guy]

Yes, I do know the general date of the research. Do you have the actual original journal articles? I have never seen these.



You should be more specific for readers here. If you combine two sounds of equal intensity, and they are non-coherant(that is, not in identical phase, at least within a few degrees of each other), then summing the two will have a 3dB increase in SPL. If, however, the two sources are coherent, then there will be a 6dB increase in SPL(for example, two identical subwoofers sitting next to each other).




I am very familiar with the equal loudness contour charts/research. But I must say, 6dB increase, overall, sounds like 2x the loudness to me in virtually every circumstance. This is why I want to read the full original research articles: to understand the precise conditions under which these tests were performed, as well as to review the statistical data acquired.

-Chris

I have never read the the original articles either. I will have to do some digging. I have a feeling it is in the audiology and medical literature of the time.

 

[highfihoney]

OK, to make you all happy, here's the math on a 20 amp circuit.

20amps x 120volts = 2400va (watts) x .85 (maximum sustained current draw on a circuit per NEC) = 2040 watts x .60 (60% efficiency of average a/b class amp) = 1224 spontanious current draws without negligeable effects on the circuit can be 3 times the continuous draw limit = 3672 watts peak power output.

Any arguements on the math please let me know!

Looks pretty spiffy to me .

 

[cbraver]

Let's review 3 possible options...

(1) Your imagination at play/placebo.

(2) The Dynaudio speakers have some very demanding current/electrical phase issues that the receiver was not designed to handle, thus causing audible levels of clipping when using the receiver.

(3) You listen at extreme SPLs using dynamic music, and/or have extended listening distance(s) and/or low efficiency speakers requiring far more power than the average person.

(4) Any combination of the previous 3.

-Chris

Normally I'm a big believer in the placebo affect, but not this time. I vote 2 and 3.

Chris, I'm very familiar with Dynaudio 17W-75 drivers in all of their guises. However you put two of those together you will have a difficult load to drive. They are not that efficient, and the impedance and characteristics are such they really do require high current delivery. I can accept that they would not be good performers with a receiver.

That goes back to my question though. Some previous posters are of the belief that 25W would have been fine for even my loudest passages, which the Pioneer would have been just fine for, but wasn't. So what gives?

As has explained before the db scale is a log scale. So if you have 100 watts per channel, to have it twice as loud you need 1000 watts per channel, assuming the speakers are the same, and they speakers don't exhibit thermal compression, which they probably will. Quite likely they will burn up. Classical music in particular requires large power reserves, because the dynamic range is so wide.

I understand. It's generally 6dB for double the percieved loudness, 5dB with room gain.

OK, to make you all happy, here's the math on a 20 amp circuit.

20amps x 120volts = 2400va (watts) x .85 (maximum sustained current draw on a circuit per NEC) = 2040 watts x .60 (60% efficiency of average a/b class amp) = 1224 spontanious current draws without negligeable effects on the circuit can be 3 times the continuous draw limit = 3672 watts peak power output.

Any arguements on the math please let me know!

Thanks!

I'm not trying to throw sticks in the fire, I just figured my example (inefficient speakers coming alive with some power) might help clarify this discussion.

 

[B3Nut]

This is the crux of the tube versus solid state debate. Tube amps are biased class A.

Not to take away from the many excellent points you raise, and not to sound too pedantic, but I would like to point out that most popular push-pull tube amplifiers are in fact Class AB1 circuits. It is of course possible to construct an amplifier of any operating class from vacuum-tubes; indeed most RF transmitters operate in Class C. Single-ended tube amplifiers (indeed, all single-ended audio circuits) are of course class A as running a single-ended audio stage in anything but results in horrific distortion.

Then cbraver asked:

That goes back to my question though. Some previous posters are of the belief that 25W would have been fine for even my loudest passages, which the Pioneer would have been just fine for, but wasn't. So what gives?

Given that the Dynaudios have been shown to be a reactive load, they presented the Pioneer with a load that it was unable to drive. A reactive load causes the voltage waveform and current waveform to go out of phase, which results in little power (wattage) being dissipated into the load but the load still has the voltage across it and is asking for a certain amount of current in amperes to be provided, and if the amplifier cannot provide it the amplifier will clip, supply rails will sag, etc. In some cases this the amplifier or receiver can be destroyed if it doesn't go into protection. Such loads usually don't behave this way at all frequencies, but when they do they can give an amplifier hell. These are the loudspeakers that simply won't perform at their best without the big iron behind them, there's just no way around it. BTW the Crown is an excellent choice, they build a dependable product and stand behind it. Good folks down there in Elkhart.

Todd in Cheesecurdistan

 

[Joe Schmoe]

Riiight. You guys are seriously claiming that there are people who can hear the difference between class A, Class C, etc? That is a DBT I would love to see!

 

[AcuDefTechGuy]

Emotiva states so on their site. Outlaw are very forthcoming, and state their protection is by opto couplers. That will be one of those opto MOSFET circuits that I previously sent you. So in terms of protection Outlaw are very up to date.

I read on-line Bob Carver's SunfireTGA-7400 amp. It states: "Each Current Source output has an in-line fuse to protect your speakers. If one ever opens, there will be no output to that speaker."

I thought fuses alone were not good enough to protect speakers?