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Oh yes, the Great Amplifier question


wvuvt1
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So..... I have spent now hours trying to find the right answer to this question as I'm sure many of you can understand. Matching an AMP to the RP-8000F speakers. My concerns are most of what I read online says to get an amp that can push 1.5 - 2 X the wattage that the speaker can produce. Most of the responses to message boards I see online say anything close to the wattage of the speaker should be fine for Klipsch due to their efficiency, but I would like more specific direction. I have a large room that is about 20x30. The owners manual for the RP-8000F says reads:

 

"Klipsch speakers are highly efficient and will operate easily on a wide variety of amplifiers. All Klipsch speakers are 8-ohm compatible and can be driven to very high levels with low distortion. Due to the high output levels Klipsch speakers are capable of reproducing, exercise caution with the volume control. Excessive volume over long periods can permanently damage your hearing. Overdriving your amplifier could also damage your speakers. Check with your dealer or amplifier manual to make sure your particular amplifier is best suited to your application. We want you listening for a lifetime." 

 

 

 

So really I'm down to a few choices at this point

 

The yamaha A-S801 which drives 8 ohms at 140 watts per channel

 

or something more powerful like

 

Emotiva XPA-2 which drives 300 watts per channel

 

Help :)

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Remember it’s not just about power delivery, but also quality of watts. I’d probably take a hard pass on the Emotiva, more brawn than you need with little finesse. Also consider tube integrated amps in whatever your budget calls for.

 

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@wvuvt1,

 

Welcome to the forum.

 

I have driven my RF-63s with my 90w/ch@8ohms Yamaha A-S1000 in my 5000 cu ft room and believe me it drives them with ease at higher volumes and high transient peaks.  Bass drive is fast tight and punchy.  That Yamaha A-S801, though not the 48 lbs beast that the A-S1000 is, should do a fine job with the RP-8000Fs.

 

Bill

 

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I think most people, including me until a few years ago, miss the real question... Which watt sounds best to you?  If you can hear a few amps to find the sound you like, the watts question may become less important?

 

For instance I prefer vintage amps to more modern AVR, chip and power amps, the few I’ve heard. I really like tube amps but they are a non-starter with the wife (little fingers could get burnt)... so they are out.  Someday,I may acquire a First Watt amp hoping to hear near tube sound. 

 

Good luck in your search.

 

 

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Dear @wvuvt1,

 

Welcome to the forum!

 

The Yamaha really is only 100 watts per channel, RMS .  It is safest to go by the RMS rating.  According to Yamaha, Minimum RMS Output Power (8 ohms, 20 Hz-20 kHz) = 100 W + 100 W (0.019% THD).  I don't see whether that is with both channels driven -- maybe it is specified  somewhere else.   It is preferable for the power spec to be with both channels driven, so the power supply is properly stressed during the test.  Nearly all amplifiers will produce instantaneous peaks at a higher level (e.g. 1 to 3 dB higher) but only for a moment.

 

The Emotiva, according to Emotiva, has Power output: 300 watts/channel RMS into 8 Ohms; two channels driven.  I don't see whether that is the figure from 20 Hz - 20Khz.  It should be, but I'd guess that it is, since manufacturers tend to fudge their specs less with separates, like power amps.  Beware, though, if you find the power rating is at 1K only, as is occasionally done by some.  

 

You have a BIG room.  You don't say how high the ceiling is, but, if it is 8 feet, you have a 4,800 cu. ft. room, 1.13 times as big as mine, so I'll take that into account.  Dolby and THX, for a concert hall or theater, require the ability to produce instantaneous peaks of 105 dB above 80 Hz, and 115 dB below 80 Hz.

Because of early room reflections in rooms our size, which make the sound seem louder than it really is, Dolby/THX says we can get along with peaks that are 5 dB less, so 100 dB, and 110 dB below 80 Hz.  I assume you are not using a subwoofer.  On Fanfare for the Common Man, The Great Gate of Kiev, the finale of most Beethoven or Mahler symphonies, I can measure 100 to 105 db, C wt., "fast" rather easily, a few times even more.  Sometimes people don't hear very brief clipping, which, I assume might still blow a tweeter.

 

The Klipsch RP 8000 F has a sensitivity ("efficiency") of 98 dB at 2.83v (1 watt into 8 ohms) at 1 meter, not at listening position!  A Klipsch engineer (not Roy) told me that would be the sensitivity in the "typical" living room (rooms provide room gain and boundary gain).  To make the sensitivity more like the AES standard, he advised subtracting 4 dB from most Klipsch sensitivity ratings.  So, to be conservative, lets use 94 dB as the sensitivity.  I happen to have a chart that lists dB produced and watts needed for that Sound Pressure Level at a listening position 13 feet away (instead of the sensitivity spec at 1 Meter), and I adjusted it for your room size.  For medium level music, not peaks, you would need less than 1 watt.  Let's say the Emotiva will produce peaks 3 dB over the RMS rating.  To get 110 dB peaks, you might need peak power of 250 watts, or 125 watts RMS.  The Emotiva is looking good right now.

 

Read reviews of both amps.

 

Ask @Shakeydeal what he means by "little finesse."  Compared to what?  The Yamaha?

 

Listen to any amps you are considering, if you can.

 

15 hours ago, wvuvt1 said:

1.5 - 2 X the wattage that the speaker can produce ...

[my bolding, italics and underline]

 

You may know this, but speakers don't produce electrical wattage (unless they are "powered" like a subwoofer, i.e., contain their own amplifier).  The RP8000F is a good, but unpowered, speaker; most speakers are unpowered.  Unscrupulous dealers -- often big box stores --may say a given speaker is a "150 watt speaker," or a "600 watt speaker," etc., but there is no such thing.  Some sales people may be mistrained to (unknowingly?) speak this way to make people think a speaker is powerfulA speaker is a transducer that changes electricity into sound.  The output of a speaker can be specified in acoustical watts but almost never is; just know these are not electrical watts, and these are not what dealerships, manufacturers, or big box stores mean.  The Sound Pressure Level in decibels is talked about in two ways by manufacturers:  Sensitivity ("efficiency")-- see above, and Power Handling (your speakers have a power handling of 150 watts/ 600 watts peak.  Once Paul Klipsch was asked what manufacturers meant by "Power Handling."  He said, "Probably not a lot."

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45 minutes ago, garyrc said:

The Yamaha really is only 100 watts per channel, RMS .  It is safest to go by the RMS rating.  According to Yamaha, Minimum RMS Output Power (8 ohms, 20 Hz-20 kHz) = 100 W + 100 W (0.019% THD).  I don't see whether that is with both channels driven -- maybe it is specified  somewhere else.   It is preferable for the power spec to be with both channels driven,

I agree.

 

Found this bench test with both channels driven full bandwidth.

https://www.audioholics.com/amplifier-reviews/yamaha-a-s801-amplifier-review/yamaha-a-s801-measurements

 

Yamaha A-S801 Full Power Bandwidth Continuous Sweep (185wpc, 4 ohms)

The A-S801 produced respectable output on the continuous sweep tests.  For 8 ohms, two channels driven, output was around 105 watts/channel and 185 watts/channel for 4 ohms under 0.01% THD+N (well below clipping).  

 

# of CH Test Type Power Load THD + N
2 CFP-BW 105 watts 8 ohms .01%
2 CFP-BW 185 watts 4 ohms .1%
1 1kHz Psweep 139 watts 8 ohms 0.1%
1 1kHz Psweep 148 watts 8 ohms 1%
2 1kHz Psweep 118 watts 8 ohms 0.1%
2 1kHz Psweep 125 watts 8 ohms 1%
1 1kHz Psweep 228 watts 4 ohms 0.1%
1 1kHz Psweep 241 watts 4 ohms 1%
2 1kHz Psweep 188 watts 4 ohms 0.1%
2 1kHz Psweep 199 watts 4 ohms 1%
2 Dynamic PWR 156 watts 8 ohms 1%
2 Dynamic PWR 260 watts 4 ohms 1%
1 Dynamic PWR 165 watts 8 ohms 1%
1 Dynamic PWR 295 watts 4 ohms 1%

 

 

Bill

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20 hours ago, Shakeydeal said:

Remember it’s not just about power delivery, but also quality of watts. I’d probably take a hard pass on the Emotiva, more brawn than you need with little finesse. Also consider tube integrated amps in whatever your budget calls for.

 

Thanks a lot for this advice, this makes sense. I think just looking at watts is a rookie temptation I will have to remind myself to try and avoid. But what do you look for when trying to see if an amp is high "quality". Maybe the total harmonic distortion (THD)?

 

10 hours ago, garyrc said:

Dear @wvuvt1,

 

Welcome to the forum!

 

The Yamaha really is only 100 watts per channel, RMS .  It is safest to go by the RMS rating.  According to Yamaha, Minimum RMS Output Power (8 ohms, 20 Hz-20 kHz) = 100 W + 100 W (0.019% THD).  I don't see whether that is with both channels driven -- maybe it is specified  somewhere else.   It is preferable for the power spec to be with both channels driven, so the power supply is properly stressed during the test.  Nearly all amplifiers will produce instantaneous peaks at a higher level (e.g. 1 to 3 dB higher) but only for a moment.

 

The Emotiva, according to Emotiva, has Power output: 300 watts/channel RMS into 8 Ohms; two channels driven.  I don't see whether that is the figure from 20 Hz - 20Khz.  It should be, but I'd guess that it is, since manufacturers tend to fudge their specs less with separates, like power amps.  Beware, though, if you find the power rating is at 1K only, as is occasionally done by some.  

 

You have a BIG room.  You don't say how high the ceiling is, but, if it is 8 feet, you have a 4,800 cu. ft. room, 1.13 times as big as mine, so I'll take that into account.  Dolby and THX, for a concert hall or theater, require the ability to produce instantaneous peaks of 105 dB above 80 Hz, and 115 dB below 80 Hz.

Because of early room reflections in rooms our size, which make the sound seem louder than it really is, Dolby/THX says we can get along with peaks that are 5 dB less, so 100 dB, and 110 dB below 80 Hz.  I assume you are not using a subwoofer.  On Fanfare for the Common Man, The Great Gate of Kiev, the finale of most Beethoven or Mahler symphonies, I can measure 100 to 105 db, C wt., "fast" rather easily, a few times even more.  Sometimes people don't hear very brief clipping, which, I assume might still blow a tweeter.

 

The Klipsch RP 8000 F has a sensitivity ("efficiency") of 98 dB at 2.83v (1 watt into 8 ohms) at 1 meter, not at listening position!  A Klipsch engineer (not Roy) told me that would be the sensitivity in the "typical" living room (rooms provide room gain and boundary gain).  To make the sensitivity more like the AES standard, he advised subtracting 4 dB from most Klipsch sensitivity ratings.  So, to be conservative, lets use 94 dB as the sensitivity.  I happen to have a chart that lists dB produced and watts needed for that Sound Pressure Level at a listening position 13 feet away (instead of the sensitivity spec at 1 Meter), and I adjusted it for your room size.  For medium level music, not peaks, you would need less than 1 watt.  Let's say the Emotiva will produce peaks 3 dB over the RMS rating.  To get 110 dB peaks, you might need peak power of 250 watts, or 125 watts RMS.  The Emotiva is looking good right now.

 

Read reviews of both amps.

 

Ask @Shakeydeal what he means by "little finesse."  Compared to what?  The Yamaha?

 

Listen to any amps you are considering, if you can.

 

[my bolding, italics and underline]

 

You may know this, but speakers don't produce electrical wattage (unless they are "powered" like a subwoofer, i.e., contain their own amplifier).  The RP8000F is a good, but unpowered, speaker; most speakers are unpowered.  Unscrupulous dealers -- often big box stores --may say a given speaker is a "150 watt speaker," or a "600 watt speaker," etc., but there is no such thing.  Some sales people may be mistrained to (unknowingly?) speak this way to make people think a speaker is powerfulA speaker is a transducer that changes electricity into sound.  The output of a speaker can be specified in acoustical watts but almost never is; just know these are not electrical watts, and these are not what dealerships, manufacturers, or big box stores mean.  The Sound Pressure Level in decibels is talked about in two ways by manufacturers:  Sensitivity ("efficiency")-- see above, and Power Handling (your speakers have a power handling of 150 watts/ 600 watts peak.  Once Paul Klipsch was asked what manufacturers meant by "Power Handling."  He said, "Probably not a lot."

Thank you so much, such a thoughtful response

 

I have gone back and looked at all the respective spec sheets for the AMPs I was considering, some of the manufacturing labeling is quite deceiving. Looking at RMS over the correct range of 20-20k hz is key, I can see where sometimes it is very confusing (possibly on purpose).

 

I took your advice and looking back at the emotiva, they thankfully list their models at 20-20k hz. The BasX A2 model drives 160 w over 2 channels driven and the aforementioned XPA-2 model drives 300 watts (also listed over the 20-20Hz). I think I'm going to go with the Emotiva, they seem to just have more power than other companies and are quite transparent with their numbers which I like. It seems like all their amps also have THD <.1 so I don't think im sacrificing much quality either

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Don’t worry about specs. Unfortunately you have to actually hear a piece of gear in your own system to get a full appreciation for it. Reviews can be helpful, both professional and amateur if you are familiar with a reviewers taste and gauge what they hear by taking their system components into account.

 

Emotiva will probably sound ok, but it’s geared towards the entry level crowd and those who care more about wpc than actual sound quality. I’d suggest either buying a used amp at a price you can turn it around if needed. Or buy from a retailer with a liberal return policy.

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