High power vs Low power Amp sound

[simonleemd]

Hi,I have been puzzled by the sonic differences between the LOWER power amp vs HIGHER power amp from the same amp manufacturer.Here is my question -- Supposed with the 250Watter,I set the Preamp volume to 8:30 position (this is optimal sound level for me); by using the 160 Watter, I crank the Preamp volume control to 9:30 or even slightly more/ to get the SAME sound level as with the 250 Watter);would I be getting a better Bass reproduction??(perhaps). But then again, the MORE volume would render sonic distorsion ?
I have been suggested by the amp manufacturer that "there is absolutely no sonic differences between the 160 Watter and the 250 Watter Amp ;
Unless you have very inefficient speakers, there is no reason at all to choose the 250 Watter amplifier and pay the higher cost."
I would like very much to know more of your experiences in using the Lower power vs the Higher power amp- whats the sonic differences if any ?
Thanks in advance
Simon

[mtrycraft]

Hi,I have been puzzled by the sonic differences between the LOWER power amp vs HIGHER power amp from the same amp manufacturer.Here is my question -- Supposed with the 250Watter,I set the Preamp volume to 8:30 position (this is optimal sound level for me); by using the 160 Watter, I crank the Preamp volume control to 9:30 or even slightly more/ to get the SAME sound level as with the 250 Watter);

Two amps, volume control position has no relationship. You should actually use an SPL meter and test tone to be sure they are indeed at different positions for the same levels. In the end, it is irrelevant but to your curiosity.


[b]would I be getting a better Bass reproduction??(perhaps). [b]

Depends. Bass from the main left/right speakers? The 250 watt amp has about a 2 dB volume advantage over the 160 watt amp. On second thought, at bass frequencies, especially at the lower end of it, is beyond JND detection.



But then again, the MORE volume would render sonic distorsion ?

Not unless you are exceeding the design limits.


I have been suggested by the amp manufacturer that "there is absolutely no sonic differences between the 160 Watter and the 250 Watter Amp ;

Side by side, they are correct if neither is driven past its design limits. In mid band where your ear is more sensitive that 2 dB difference may be useful in rare occasions But those occur at peaks. So, in the end, the maker is correct


Unless you have very inefficient speakers, there is no reason at all to choose the 250 Watter amplifier and pay the higher cost."

Well, that depends on a few choices: cost difference, issue of preference comfort level of having more power just in case.

the Lower power vs the Higher power amp- whats the sonic differences if any ?
Thanks in advance
Simon

In this case trust the amp maker. He is correct.

[simonleemd]

Thanks mtrycraft. I find your explaination educative and your advises is well taken.. BTW, whats JND stands for ? Please allow me just to "refreshed" my question though-- If I set the Preamp volume knob on s specific/fixed position ( that I can hear enough details of a full scale symphony e.g Mahlers' or Bruckner's on CD);by hooking up with (A) Higher power (250 Watter) then switches to (B) Lower power(160 Watter) Amp; would I be getting louder ,more details and perhaps even better Bass with (A) ?? or would I be getting a mellower and softer sound and less details less clarity with (B)???

I w'd appreciate more of your opinion,explaiantion and advises
Thanks in advance
Simon

[Geoffcin]

Hi,I have been puzzled by the sonic differences between the LOWER power amp vs HIGHER power amp from the same amp manufacturer.Here is my question -- Supposed with the 250Watter,I set the Preamp volume to 8:30 position (this is optimal sound level for me); by using the 160 Watter, I crank the Preamp volume control to 9:30 or even slightly more/ to get the SAME sound level as with the 250 Watter);would I be getting a better Bass reproduction??(perhaps). But then again, the MORE volume would render sonic distorsion ?
I have been suggested by the amp manufacturer that "there is absolutely no sonic differences between the 160 Watter and the 250 Watter Amp ;
Unless you have very inefficient speakers, there is no reason at all to choose the 250 Watter amplifier and pay the higher cost."
I would like very much to know more of your experiences in using the Lower power vs the Higher power amp- whats the sonic differences if any ?
Thanks in advance
Simon

Is why you would choose the more powerful amp. Real world tests prove that dynamic limitations of low wattage amps are reached far earlier than would be expected. Bass reproduction is one area where it's clearly noted, as the transient peak of a kick drum can easily reach the limit of a lower powered amp even when the music is playing at a moderate level. I've noted this on amps as high as 200wpc with moderately inefficient speakers. Amp design comes into play too, as there are many quality amps that feature dynamic headroom far and above their rated output.

[skeptic]

The selection of an amplifier based on power requirements should be made as part of an engineering decision about the sound system as a whole. This means the efficiency of the loudspeakers, the size of the room, its acoustics, the type of music to be played and the maximum undistorted loudness that will have to be attained. Just as you would not power a Volkswagon Beetle with an engine intended for a jet fighter plane, you would not power a jet fighter with an engine appropriate for a Volkswagon Beetle. This is why engineering a sound system is so important and something that most audiophiles don't do. They pick a piece here that they like, a piece there, throw them together and hope for the best. Most experts will advise someone contemplating a sound system to pick the speakers first. This makes wonderful sense. The choice of speakers will have the greatest bearing on the overall sound of the system. The choice of speakers will define the size of the amplifier required. Engineers usually design from the back to the front. That means they look at the ultimate requirement and work backwards. Start with the sound levels required and the room and pick the speaker you want to install in it. Then pick an amplifier that will satisfy the requirements of the speaker. If you choose an efficient horn speaker for a modest size room with live acoustics, a 200 wpc amplifier is far to powerful. If you choose an acoustic suspension bookshelf type for a large room with dead acoustics, an 8 wpc SET won't work because not enough power is available. Once the power requirements are determined, then determine the functional requirements. Set a budget, and finally narrow down your choices from models available which meet your needs. All other things being equal (they seldom are) comparable models with marginally different output power capabilities will not make an audible difference. In the case of a 160wpc versus 250 wpc amplifier, the difference is a two decible increase in the maximum undistorted volume the systems can play at if the loudspeakers can handle it. This is not significant enough to matter. The volume control setting is irrelavent as long as it can drive the amplifier to maximum output at a maxumum setting. The action of the volume control is similar to the action of a spring under the gas pedal in your car. It has no relationship to how powerful the engine is under the hood. All you want is to be sure at full throttle you can get whatever power is available. If there is any audible difference between ampliers operating within their rated power levels, they are related to complex factors not associated with how much power they can deliver when pushed to their limiit.

[mtrycraft]

Thanks mtrycraft. I find your explaination educative and your advises is well taken.. BTW, whats JND stands for ?

Just Noticable Differences. While some may believe the infinite capability of hearing, it is actually limited a lot. JND is the amount of volume change that is needed before you will notice a difference. This depends on a lot of aspects in audio such as frequency, type of signal such as test tones (very sensitive signal) or music, and even th evolume itself. Low frequency band and the high frequency band your hearing is much less sensitive to volume changes. Like an bell curve unside.

Please allow me just to "refreshed" my question though-- If I set the Preamp volume knob on s specific/fixed position ( that I can hear enough details of a full scale symphony e.g Mahlers' or Bruckner's on CD);by hooking up with (A) Higher power (250 Watter) then switches to (B) Lower power(160 Watter) Amp; would I be getting louder ,more details and perhaps even better Bass with (A) ?? or would I be getting a mellower and softer sound and less details less clarity with (B)???Simon[/QUOTE]



Not a simple answer. Firstly, your two amps may have a different output with the volume control in a fixed position and the input sigan being the exact same level. Different sensitivity, etc. So, you cannot compare the two amps under such conditions you posted. But, if you adjusted the preamp volume so that with a known fixed input signal such as a test tone, both amps would produce the same volume(measured with a meter or voltmeter at the speaker terminal) your overall sound would be unchanged perceptibly untill you come to a passage where the signal demands power more than 160 watts, or as was pointed out, the dynamic capability of that 160 watt amp vs the 250 watt amp. If the level needed is withing the power range of both amps, no reason why they would be audibly be different.

[E-Stat]

I would like very much to know more of your experiences in using the Lower power vs the Higher power amp- whats the sonic differences if any ?

Sometimes the reverse is true - the smaller amp sounds "better" within its power range due to fewer output devices, simpler design, etc.

As skep pointed out, the real question is determining your speaker's needs based on environment, desired level and recordings. You may be surprised, however, how much power is required by really dynamic content.

rw