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Discussion Starter · #1 ·
I am looking to purchase an amp to use with the pre-outs on my Denon X4000, but I am confused on how to choose an amp. I am looking to power front speakers. I am currently looking at the following amps, but I am open to other suggestions.


What do people think of the following amps, in general? What about in terms of price/performance?

Synergy 240/3 (double die) - Audio by Van Alstine - ~$1600

XPA-3 - Emotiva - ~$800

XLS DriveCore 1500/2000 - Crown Audio - ~$330 (cosmetic damage or open box)/~$500


Any other amp suggestions? I have seen lots of people happy with the Emotiva. I have read some trusted recommendations for Van Alstine products. I have not heard as much about Crown Audio but the price is really good.


I am also confused by whether those amps will need (or rather benefit) from a device like the Art CleanBox which will convert from consumer pre-out levels to pro-audio input levels.
 

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Quote:
Originally Posted by MarsianMan  /t/1525179/amp-selection-ava-synergy-240-3-emotiva-xpa-3-crown-xls-2000#post_24551937



Any other amp suggestions? .

Sure. Your receiver has perfectly competent amplifiers. Use them.
 

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Discussion Starter · #3 ·

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Originally Posted by FMW  /t/1525179/amp-selection-ava-synergy-240-3-emotiva-xpa-3-crown-xls-2000#post_24552026


Sure. Your receiver has perfectly competent amplifiers. Use them.

Wow, thanks..... The urge to post a snarky comment is strong, but I will assume that is a consice attempt to be helpful rather than funny/smart.



The X4000's amplifiers may be perfectly competent, but I would like to experiment with more (clean) power.
 

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Fine r to experiment if you have fhe cash. If like me you listen 6 dB or more below reference you may not use even 50watts for peak volume and will have vr plenty o power from the receiver. See in the silent parts you use essentially zero power and at casual conversation levels (65 dB) tenth of a watt if your system is inefficient. To hit a loud 85dB would take 10 watts im such a system. If you have clean flat powerto the level you need you don't need more. X SPL at your listening position requires Y watts and ohms law makes it certain that no matter how much power your amp could provide it will only provide Y watts at a given SPL. Once distortion is at an inaudible level, more inaudibler is imperceptibly different
 

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Quote:
Originally Posted by MarsianMan  /t/1525179/amp-selection-ava-synergy-240-3-emotiva-xpa-3-crown-xls-2000#post_24552086


Wow, thanks..... The urge to post a snarky comment is strong, but I will assume that is a consice attempt to be helpful rather than funny/smart.



The X4000's amplifiers may be perfectly competent, but I would like to experiment with more (clean) power.

Then do it and stop being snarky with me. I don't care what you do. I was giving honest advice. Forget I offered it.
 

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Discussion Starter · #6 ·

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Originally Posted by FMW  /t/1525179/amp-selection-ava-synergy-240-3-emotiva-xpa-3-crown-xls-2000#post_24552865


Then do it and stop being snarky with me. I don't care what you do. I was giving honest advice. Forget I offered it.
That's like me asking you for travel suggestions and you telling me to stay home. It's not really helpful. You just side skirted my question. I do appreciate you taking time to respond though.
 

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Discussion Starter · #7 ·

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Originally Posted by JHAz  /t/1525179/amp-selection-ava-synergy-240-3-emotiva-xpa-3-crown-xls-2000#post_24552174


Fine r to experiment if you have fhe cash. If like me you listen 6 dB or more below reference you may not use even 50watts for peak volume and will have vr plenty o power from the receiver. See in the silent parts you use essentially zero power and at casual conversation levels (65 dB) tenth of a watt if your system is inefficient. To hit a loud 85dB would take 10 watts im such a system. If you have clean flat powerto the level you need you don't need more. X SPL at your listening position requires Y watts and ohms law makes it certain that no matter how much power your amp could provide it will only provide Y watts at a given SPL. Once distortion is at an inaudible level, more inaudibler is imperceptibly different

The purpose of getting the amp is to achieve a higher SPL otherwise I would stick with the X4000's internal amps. I do not want to push my amp too close to 0 dB because I am worried about clipping.
 

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Quote:
Originally Posted by MarsianMan  /t/1525179/amp-selection-ava-synergy-240-3-emotiva-xpa-3-crown-xls-2000#post_24555309


The purpose of getting the amp is to achieve a higher SPL otherwise I would stick with the X4000's internal amps. I do not want to push my amp too close to 0 dB because I am worried about clipping.

you assume that you're pushing the amp hard at zero dB. Maybe not. Zero db means (assuming you calibrated with Audyssey) that you'll have the power to hit 105 dB per speaker at the listening point on peaks (whether you catually get there depends on speaker compression). But if one speaker is calibrated at -6 dB and another at 0 dB, then the power to hit that 105 dB is four times higher for the speaker that's calibrated at zero. IOW, the volume control setting tells you essentially nothing about actual power output. If you really need more power, you do. If you really need more power it's because the amp is distorting on loud parts at reference (or near reference). Of course, if you hear distortion, the first question is whether it's from the speakers, which are likely to have harmonic distortion a good 10 times higher at their limits than the amps' typical nominal "clipping" distortion level of one percent or lower . . . .
 

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Discussion Starter · #9 ·

Quote:
Originally Posted by JHAz  /t/1525179/amp-selection-ava-synergy-240-3-emotiva-xpa-3-crown-xls-2000#post_24555773


you assume that you're pushing the amp hard at zero dB. Maybe not. Zero db means (assuming you calibrated with Audyssey) that you'll have the power to hit 105 dB per speaker at the listening point on peaks (whether you catually get there depends on speaker compression). But if one speaker is calibrated at -6 dB and another at 0 dB, then the power to hit that 105 dB is four times higher for the speaker that's calibrated at zero. IOW, the volume control setting tells you essentially nothing about actual power output. If you really need more power, you do. If you really need more power it's because the amp is distorting on loud parts at reference (or near reference). Of course, if you hear distortion, the first question is whether it's from the speakers, which are likely to have harmonic distortion a good 10 times higher at their limits than the amps' typical nominal "clipping" distortion level of one percent or lower . . . .

The volume control setting might not tell me anything about power output directly, but the increase in SPL does imply more power used. My speakers are Philharmonitors (87 dB sensitivity) and they should be able to handle more power. According to this calculator , I need ~200W per channel (already past the X4000's rating) for 98 dB at 2 meters (actual distance is 7'-8').


I am looking to use an external amp precisely because I am worried about harmonic distortion causing excess power to be sent to the tweeter and frying it. That is also why I wanted to know what people thought of the amps I mentioned. They cover range of "inexpensive" amps.


I am on this forum to learn, so I appreciate making sure I understand amp basics.
If I am mistaken please correct me.
 

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if you don't hear the distortion, it cannot harm your tweeters. People talk about square waves form clipping amps. Amps are alomst universally specified as clipping at one percent or less THD. A square wave consists of a fundamental frequency and over harmonics that would add up to over 40 percent THD. Not something you could stand to listen to at home (whether I get close to there with my guitar amps is another question . . . )


By all means if you will be happier get more power. My issue is that many folks (not you) seem to think the 50 watts or so they actually use on peaks will somehow be different or a more powerful 50 watts if it comes from a 200 watt amp than if it comes from a 50 watt amp. As long as distortion is inaudible, higher power simply makes it more inaudible which is of value only to our egos (okay, maybe my id wants some big power but we'll leave that for another day). Ohm's law prevents the amp from sourcing more current for any given voltage regardless of the amp's capability (as long as you're in the amp's linear range - otherwise voltage will sag onaccounta its the law), and the speaker is following the voltage . . . .


every three dB is double or half the power, so if you listen what most folks would describe as "one notch" below reference, you're power needs are cut in half. I'm well below that and I have a sub taking the brunt of the power requirements anyway, so my power needs are modest, and I could stack Brystons or Krells to the ceiling and unless they are not linear, I'd hear no difference from the pure huge available power that I never use . . .


And it is still IMO appropriate to ask yourself whether your speakers remain linear at 105 db. That is, will you get 105 dB from 300 watts or whatever, or will the speaker actually only give you 101 dB or maybe 102 dB (ie speaker compression). You cannot overcome compression with power alone, you'd need some kind of an expander (not available anywhere that I know of) to feed the speaker the maybe 800 watts it needs to really hit 105 dB (with 20 or 30 percent speaker distortion . . .) assuming you can actually push it there. A fair rule of thumb (AFAIK, it's really from the musical instrument/live sound side of the world) is that a speaker can respond linearly to about one half of its thermal (ie the rating you see) power limit. After that, for every dB the power goes up, the speaker goes up less than one dB . . .
 

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Quote:
Originally Posted by MarsianMan  /t/1525179/amp-selection-ava-synergy-240-3-emotiva-xpa-3-crown-xls-2000#post_24556306


The volume control setting might not tell me anything about power output directly, but the increase in SPL does imply more power used. My speakers are Philharmonitors (87 dB sensitivity) and they should be able to handle more power. According to this calculator , I need ~200W per channel (already past the X4000's rating) for 98 dB at 2 meters (actual distance is 7'-8').


I am looking to use an external amp precisely because I am worried about harmonic distortion causing excess power to be sent to the tweeter and frying it. That is also why I wanted to know what people thought of the amps I mentioned. They cover range of "inexpensive" amps.


I am on this forum to learn, so I appreciate making sure I understand amp basics.
If I am mistaken please correct me.

Hi MarsianMan,


I used the following site to calculate SPL for the small satellite speakers from KEF (E301) which has lower sensitivity than your Philharmonitors 2. http://myhometheater.homestead.com/splcalculator.html


When inputting data for a pair of Philharmonitor 2 speakers with the sensitivity of 87dB, the listening distance of 8', speakers placed away from the wall and 100W of amp power - the SPL came out to 102dB. If you place the pair of Philharmonitor 2 speakers near the wall (2 to 4 feet) the SPL comes to 105dB. If the speakers are near the corner (1.5' to 2') then the SPL is 108dB. Increasing the number of speakers also affects the dB value.


Play around with the online calculator to see what the optimal power, placement and listening distance you are comfortable with.


I don't have the Denon X4000 AVR and not aware of it's maximum power at 8 Ohms is. What you would want to do is look for the value that has the lowest distortion as this is more reliable and meets the desired SPL using the online calculator.


The woofer in the Philharmonitor 2 will require significant amounts of power to produce the desired SPL at the listening position. One of the tricks to manage this power is by off-loading the low frequency power demand of the Philharmonitor 2 woofer into the sub. The .1 the the 5.1 (or 2.1) speaker system. This can be accomplished via the AVR by having the cross over frequency set to say 80Hz or higher, depending on your tastes. Set the Philharmonitor to small in the Audyssey setting with the X4000. This way the Philharmonitor tweeter + mid range driver that doesn't require so much power can be easily driven by the X4000 and the sub takes over for lifting the heavy low frequencies.
 

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Quote:
Originally Posted by MarsianMan  /t/1525179/amp-selection-ava-synergy-240-3-emotiva-xpa-3-crown-xls-2000#post_24551937


I am looking to purchase an amp to use with the pre-outs on my Denon X4000, but I am confused on how to choose an amp. I am looking to power front speakers. I am currently looking at the following amps, but I am open to other suggestions.


What do people think of the following amps, in general? What about in terms of price/performance?

Synergy 240/3 (double die) - Audio by Van Alstine - ~$1600

XPA-3 - Emotiva - ~$800

XLS DriveCore 1500/2000 - Crown Audio - ~$330 (cosmetic damage or open box)/~$500


Any other amp suggestions? I have seen lots of people happy with the Emotiva. I have read some trusted recommendations for Van Alstine products. I have not heard as much about Crown Audio but the price is really good.


I am also confused by whether those amps will need (or rather benefit) from a device like the Art CleanBox which will convert from consumer pre-out levels to pro-audio input levels.

Of course you should make sure you need an amp. Otherwise it's money spent, and more heat and more gear and more cables etc.


If you do need an amp, the XPA-3 is pretty good. I own one. It amps the most important channels, the front channels, and will give you a lot of power in stereo. I got mine on sale making it a better deal than 800 though - I don't think I would have paid 800.


I have a Crown XLS for surround duty. Only issue was a bit of hiss, but you had to be close to the speaker to hear it. Not a show stopper. I am sure it could work well for L/R, but what are you going to do for the center? Buy two? Then the XPA-3 is starting to look like a viable option.


I can't comment on the Synergy other than to say that I personally would not pay that price.
 
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