Power amp

[Bryceo]

Been looking at to models that are held here in Australia for my main speakers only
First of all I want quality witch my Yamaha receiver already has but I'd like to boost the performance in the mains
Here's what I've been viewing and reading about
The marantz MM7025,

http://www.stereophonic.com.au/marantz-mm7025-2-channel-power-amplifier/?gclid=CKWn_vq69b0CFQlcpQodcWgAsw
And the Yamaha xh200
http://m.au.yamaha.com/en/products/proaudio/power-amps/xh200/



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[Steve81]

Doesn't look like the Yamaha amp is suitable for this task (rated into 24 ohm / 48 ohm loads for distributed systems), but this Rotel looks like a fair alternative to the Marantz for not a lot more cash:
Rotel RB 1582 Power Amp - Stereophonic
200W x 2 and the manual indicates it will work well with a 4 ohm load.

 

[AcuDefTechGuy]

What are the main speakers? What is the speaker's max rated power?

 

[Bryceo]

Yamaha ns-300x

i got a screen shoot so I no I didn't get the information wrong
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[AcuDefTechGuy]

So the 91dB/w/m speaker (quite efficient compared to most speakers) probably has a max power rating of "200W". I'd say a 100-200W into 8 ohm amp should be good.

What is the power output of your Yamaha AVR?

I also think the Rotel 1552 (120WPC x 2Ch) would work well.

Rotel RB 1552 Power Amp - Stereophonic

For 91dB/w/m, 3m distance, 103dB total SPL (very loud to me) in 2.0 music full-range, it would require 70W into 8 ohms or 140W into 4 ohms for each of the 2 speakers (if the speaker goes down to 4 ohms).

If total 2.0 volume is 100dB, it would require 40W/8 ohms or 80W/4 ohms.

 

[Bryceo]

Rx-v 2095

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[AcuDefTechGuy]

Rx-v 2095

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I believe your current Yamaha AVR has more than enough power for your speakers.

 

[AcuDefTechGuy]

Here is one source of info on amp power and speaker damage that I find interesting.

Quote from Bill Fitzmaurice Loudspeaker Design:

There are only two ways that a speaker can be damaged, both of which occur from too much input power. 1. Mechanically 2. Thermally

Every speaker has an excursion limit (often measured in mm), or how far the speaker can move forward or rearward before damage occurs. This is the mechanical limit of the speaker. This limit remains the same regardless of the use of the speaker, but the power required to reach this limit changes dependent on the enclosure. If you exceed this limit, the speaker will suffer mechanical damage, whether it's ripping your spider, bottoming out on the back plate, or any other mechanical damage. The second type, thermal damage, occurs when you exceed the thermal power handling limits of the voice coil itself. Voice coils are simple pieces of metal that will melt if too much power is applied. This limit is pretty much constant, ie. if a voice coil will be damaged at 1 kw, it will be damaged at 1kw regardless. There are two final myths to cover here. Despite the tireless efforts of some, there are still many people that believe that underpowering a speaker will damage it or that clipping will damage a speaker. Please remember that these last two thoughts are entirely UNTRUE!

BillFitzmaurice.info - View topic - Can I underpower my speakers?Will clipping hurt them?

 

[jinjuku]

I have never understood the portion of people that believe if you feed a low voltage, clipped, signal into a voice coil it will damage it. The speaker will simply play the clipped signal and sound bad.

When they have talked about high wattage and how that's better I've offered to bring over about 5Kw of power

 

[lsiberian]

I have never understood the portion of people that believe if you feed a low voltage, clipped, signal into a voice coil it will damage it. The speaker will simply play the clipped signal and sound bad.

When they have talked about high wattage and how that's better I've offered to bring over about 5Kw of power

I think it's better to have more headroom, but you can certainly blow speakers that way.

 

[RichB]

I believe the argument is that as an amp clips the distribution of power moves to the higher frequencies due to compression and distortion where the drivers are less able to handle the power.

So, a 100 watt AVR at a drunken party can be hazardous to your speakers. Not that a 500watt amp might also yield the same result.

For me, power is not about preserving your speaker but delivering an unclipped signal to your speaker to get the most out of them.

- Rich

 

[Bryceo]

If I was to get a rotel would there be a major change in the quality or loudness is the yamaha avr quality enough for the job,


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[AcuDefTechGuy]

I believe the argument is that as an amp clips the distribution of power moves to the higher frequencies due to compression and distortion where the drivers are less able to handle the power.

So, a 100 watt AVR at a drunken party can be hazardous to your speakers. Not that a 500watt amp might also yield the same result.

For me, power is not about preserving your speaker but delivering an unclipped signal to your speaker to get the most out of them.

- Rich

The argument is that if some crazy idiot tries to blow your speakers, he could do it a lot easier if you use a 1000W amp than a 100W AVR, especially when your speakers are generously rated at 200W max, which means your tweeter is rated for about 10W-20W.

Idiots blow speakers, not too little power. Another source of info:

http://www.bcae1.com/2ltlpwr.htm

 

[AcuDefTechGuy]

If I was to get a rotel would there be a major change in the quality or loudness is the yamaha avr quality enough for the job,
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If you are like most typical people who don't listen to crazy volume from a distance of 50 feet away, then your very powerful Yamaha will do the job perfectly and the Rotel or any other amp won't do anything for the sound quality.

 

[RichB]

The argument is that if some guy tries to blow your speakers, he could do it a lot easier if you use a 500W amp than a 100W AVR, especially when your speakers are generously rated at 200W max.

Idiots blow speakers, not too little power.

what tweeters handle 50 watts?
People do blow them.

You have seen this article and the measurements and findings seem sensible:

Why Do Tweeters Blow When Amplifiers Distort?

What we do see is the increase of signal level to the tweeter, with the moderate clipping example showing a 7.6dB increase. Remember that this translates to an average power increase of over 5 times to the tweeter. If the tweeter would normally be expected to handle a peak power of 15W and an average power of perhaps 5W (based on Figure 1 and a 100W amplifier), a 7dB increase will take that average to 25W! The tweeter will not survive.

- Rich

 

[AcuDefTechGuy]

what tweeters handle 50 watts?
People do blow them.

You have seen this article and the measurements and findings seem sensible:

Why Do Tweeters Blow When Amplifiers Distort?



- Rich

50W? I said 10-20W.

The more excessive the power, the more damage will occur due to mechanical and thermal damages, not due to clipping.

Normal people won't do that when they use a 100W AVR. But if that same idiot turns the volume way up on the AVR, it will just shut down. Speakers will be just fine.

Mechanical damage: Every speaker has an excursion limit. This is the mechanical limit of the speaker. If you exceed this limit, the speaker will suffer mechanical damage.

Thermal damage: occurs when you exceed the thermal power handling limits of the voice coil itself. Voice coils are simple pieces of metal that will melt if too much power is applied.

Despite the tireless efforts of some, there are still many people that believe that under-powering a speaker will damage it or that clipping will damage a speaker. Please remember that these last two thoughts are entirely UNTRUE!

Translation: UNDER-POWERING a speaker or CLIPPING will NOT damage a speaker.

One of the most famous myths regarding clipping is that it produces DC. If you look in the frequency domain using a Fast Fourier Transform, you will see the fundamental frequency and its higher order harmonics only. There will be absolutely no DC present.

The final myth is that of the still voice coil. It is perhaps the most believed myth regarding clipping. The idea is that because of the square wave, the coil is not moving during the flat portions of the signal. This is simply not true for a variety of reasons. The speaker does exhibit mechanical damping and remains in constant motion. Assuming the same voltage and excursion xmax, the cooling at any given frequency will remain the same, whether the signal is clipped or unclipped.

Summary
There are only two ways to damage a speaker: Mechanically and Thermally. The only way to do this is by applying too much input power in a given enclosure (mechanically) or too much average power over time (thermally). There is no DC in a clipped signal; the coil does not stand still; air passing over the coil (and thus cooling) is the same regardless of the waveform; and clipping is acceptable provided that the average power over time is lower than the speaker's limits. The next time you hear those famed words "your speakers died because of clipping", remember what you have learned, and above all, keep searching for the truth.

Translation: Speakers do NOT die because of CLIPPING. They die because of mechanical and thermal damages due to EXCESSIVE power.

 

[RichB]

^^^

No argument here, but there is no reason to believe that you cannot fry a tweeter with a 100 watt AVR.

I am certain however, that with full range speakers listening to music at 90 DB with 10 to 20 DB peaks, something's gotta give.
You won't blow up your speakers but, you might not be getting the most of them.

- Rich

 

[AcuDefTechGuy]

^^^

No argument here, but there is no reason to believe that you cannot fry a tweeter with a 100 watt AVR.

I am certain however, that with full range speakers listening to music at 90 DB with 10 to 20 DB peaks, something's gotta give.
You won't blow up your speakers but, you might not be getting the most of them.

- Rich

The point is that speakers don't die because of amp clipping due to underpowered amp. Speakers die because of mechanical and thermal damages due to excessive power pumping into the speakers.

You could use a 2,000W amp and still not cause mechanical and thermal damages to speakers if you do not turn the volume too high.

But the odds of causing mechanical and thermal damages to the speaker is a lot higher if your amp is 2,000W instead of 100W.

And if the speaker is damaged, it is NOT due to clipping of an underpowered amp.

 

[RichB]

^^^

The low frequency drivers are less likely to be damaged by power than the high frequency drivers.
The Revel F208s which have recommended power handling of 50 to 350 watts.
Revels can handle power and I have played the F206s at reference volume with a Parasound A21 and they never faltered.

At the same volume level, there is no reason to believe that a 2000 watt digital amp is going to blow them up any more than the 250 watt Parasound. So, I don't get that argument.

However, if we have 50 watt average and 10 Db peaks than 500 watts peak power is required. The F208s will handle the peak. An AVR is not going to cut and will current limit, compressing the sound and pushing more power to the mid-upper range than a non-clipping amp.
Power = thermal issues for high frequency drivers.

Speakers, like the Revels, are designed to produce dynamic content with minimum compression (to a point). In my experience, listening to dynamic content on speakers that can delver it faithfully actually results in lower volume levels and better sound.

If you want to protect your speakers don't under power your system, buy a preamp with a maximum volume limit, password controlled, if you have kids

- Rich

 

[PENG]

^^^

The low frequency drivers are less likely to be damaged by power than the high frequency drivers.
The Revel F208s which have recommended power handling of 50 to 350 watts.
Revels can handle power and I have played the F206s at reference volume with a Parasound A21 and they never faltered.

At the same volume level, there is no reason to believe that a 2000 watt digital amp is going to blow them up any more than the 250 watt Parasound. So, I don't get that argument.

However, if we have 50 watt average and 10 Db peaks than 500 watts peak power is required. The F208s will handle the peak. An AVR is not going to cut and will current limit, compressing the sound and pushing more power to the mid-upper range than a non-clipping amp.
Power = thermal issues for high frequency drivers.

Speakers, like the Revels, are designed to produce dynamic content with minimum compression (to a point). In my experience, listening to dynamic content on speakers that can delver it faithfully actually results in lower volume levels and better sound.

If you want to protect your speakers don't under power your system, buy a preamp with a maximum volume limit, password controlled, if you have kids

- Rich

Rich, I agree with you in theory but in practice I would hope most people don't push their amps to output 50W average. I typically listen to 75 dB SPL from where I sit and the average power is less than 0.5W (more ofen around 0.2W or less) with peaks of 10 to 20 dB maximum, more often just 6 to 12 dB peaks so my peak power is typically less than 20W. For me to listen at 50W average, I would be listening to average SPL of well over 100 dB and I would have been wearing hearing aid long ago.

Now if one does listen at 50W average using an A21, a 12 dB peak will require the A21 to output 800W, any more than that the A21 will clip too. And if the music contents itself is compressed, such as rocks and pops, the A21 will also blow tweeters of speakers rated for 200 to 300W maximum, without clipping.

I see good arguments from both side but there seem to be more truth in saying overpower blow tweeters, it is at least more technically correct. It is also true that a symmetrically alternating square wave does not contain DC, but rather, lots of higher order harmonics. However, if the square wave is asymmetrical, then it will contain a DC component, but I don't see any of this relevant to the subject matter.