Benefits of a seperate amp?

[yepimonfire]

for awhile i've been considering adding an external amplifier to my setup but haven't really decided if it's worth it or not. i am an "output junkie" (as Seth=L puts it.) but i have never really driven my Marantz into clipping or anything like that. are there other benefits besides just have more power? another thing that's making me more inclined to add one is that im running the LFE and bass through my fronts.

 

[mortonconst]

i asked the same question a while ago and i got this response.....adding a seperate quality amp is like removing a blanket from you speakers.......


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[mortonconst]

by the way...how do i create a signature?????

 

[highfigh]

for awhile i've been considering adding an external amplifier to my setup but haven't really decided if it's worth it or not. i am an "output junkie" (as Seth=L puts it.) but i have never really driven my Marantz into clipping or anything like that. are there other benefits besides just have more power? another thing that's making me more inclined to add one is that im running the LFE and bass through my fronts.

Dynamics/headroom can be improved if the separate amp is powerful enough. If they're the same output power, it's not going to be very noticeable, if at all. Big power makes a difference, though.

 

[Davemcc]

I did notice a difference when adding a modestly powered separate amp to my mid-line Denon receiver but only when driving the speakers fairly hard. It was enough difference to convince me to go to separates.

 

[j_garcia]

The difference is, with a quality separate amp, everything in that amp is dedicated to doing one thing = power. In a receiver, that one power supply has to power everything the receiver is doing and it is also typically is smaller than what you will find in a decent separate amp. Even with an amp that is similar power as the claimed power of a receiver, a decent amp can actually have more usable output because they tend to be a little more over designed compared to a receiver.

Another benefit can be offloading work from the receiver. Maybe you have power hungry mains and during heavy passages the receiver may struggle. A separate amp is using its own power supply to drive those speakers so all the channels are not fighting for current from the power supply in the receiver. That's sort of the thinking behind monoblock amps - each speaker has its own dedicated power supply, so each does not have do deal with dips/peaks from what is going on with the other speakers like it would with a shared power supply.

My receiver is 120w. I previously used 125W THX monoblocks for my front 3 and there was a definite difference compared to my receiver. Moving to the XPA-3 was an even bigger improvement.

 

[yepimonfire]

my receiver has very hefty amps in it, like i said even when running LFE through the fronts and listening at seriously loud reference levels it has never clipped or run out of juice. so i'm wondering if there would be any other improvements other then more power.

 

[Jim85IROC]

my receiver has very hefty amps in it, like i said even when running LFE through the fronts and listening at seriously loud reference levels it has never clipped or run out of juice. so i'm wondering if there would be any other improvements other then more power.

I keep trying to tell myself that there's no difference, but a friend brought over a couple different amps that he was in the process of auditioning. First was a McIntosh MC302, the other a Class D Cherry amp. In both cases, I seemed to hear a very noticeable difference between the external amp and my receiver (NAD T742), most specifically in the quality of the bass response.

I'm still not convinced that what I hear is a legit difference and not just a placebo, so when I get time I'm going to rig up a relay switch box so that I can level match then toggle back and forth. My NAD, though only rated at around 50 or 60 watts per channel, has been measured to put out close to 150 with just 2 channels driven, so I'm confident that the NAD is providing adequate unclipped volume levels... which just leaves sound quality. I've always stood on the assumption that amps sound the same, but it seems that now I might be standing on shaky ground.

 

[j_garcia]

I am very familiar with your receiver and it does have a decent amp section, but it isn't going to compete with a quality separate amp. An amp won't (shouldn't) change the way your system sounds much, it will just give you the ability to turn it up more without distortion. You may think it distortion isn't present, but it is there.

If it sounds fine at the levels that you typically listen, which would mean to me your speakers are an easy enough load for the power supply and your listening area isn't too big for the SPL you are asking of the system, then an amp probably won't benefit you. If you find yourself turning it up to the point where no matter how much you go beyond that it doesn't get any louder, then you will benefit.

My speakers are all 4 Ohm and my room is large, so the additional amplification was necessary.

 

[Davemcc]

Disregard this pre-edit post. I see you have Monitor 70's on the way. They are still 8 ohm, 90db/w. They carry about the same specs as the Monitor 40. They shouldn't require an amp either. I don't know if you would really hear a difference with a separate amp.

I tend to like difficult to drive, hard load speakers which may account for the difference I heard. I don't think the Polks are like that.

 

[yepimonfire]

actually the funny thing is it takes more power to drive the 70s then it did to drive the 40's, the same volume i would get on -30dB with the 40's, i now find myself turning it to -20dB. -20dB would have sounded unbearable with the 40's. i don't trust those sensistivity ratings polk has because out of every speaker i have ever owned none of them have had a claimed 90dB sensitivity and all of them were much easier to drive at lower volumes. also just talk to any RTI owner, all of them will say it is a very difficult speaker to drive and they have a sensitivity of like 91dB. i will say as far as the distortion levels i have noticed much clearer more "effortless" sound on receivers with significant differences in power ratings even at the same volumes.

 

[yepimonfire]

I keep trying to tell myself that there's no difference, but a friend brought over a couple different amps that he was in the process of auditioning. First was a McIntosh MC302, the other a Class D Cherry amp. In both cases, I seemed to hear a very noticeable difference between the external amp and my receiver (NAD T742), most specifically in the quality of the bass response.

I'm still not convinced that what I hear is a legit difference and not just a placebo, so when I get time I'm going to rig up a relay switch box so that I can level match then toggle back and forth. My NAD, though only rated at around 50 or 60 watts per channel, has been measured to put out close to 150 with just 2 channels driven, so I'm confident that the NAD is providing adequate unclipped volume levels... which just leaves sound quality. I've always stood on the assumption that amps sound the same, but it seems that now I might be standing on shaky ground.

you know what i find funny is that every claim made about cables and receivers and break in and every other "snake-oil" claim it usually involves the bass section amps do sound the same as far as linear response goes, amps cannot give you "warmth, brightness, softness, more bass, reduced bass etc." the only difference ive noticed in the bass section with different power rated receivers is more dynamics, lower powered receivers at high volumes seem to sound "compressed" and "strained" when heavy LFE or bass content in music such as kick drums etc come in.

 

[j_garcia]

You can have a high sensitivity speaker that is still difficult to drive due to impedance and what frequencies they are playing. Sensitivity rating does not account for your room and doesn't actually tell you what kind of load it will present to the amp. My speakers are 91dB but are also 4 Ohm making them a tougher load.

 

[yepimonfire]

i have no idea what the impedance curve of them is because polk has never published them. all i know is the 70's don't play louder or as loud as the 40's with the same volume on the same receiver.

 

[Jim85IROC]

you know what i find funny is that every claim made about cables and receivers and break in and every other "snake-oil" claim it usually involves the bass section amps do sound the same as far as linear response goes, amps cannot give you "warmth, brightness, softness, more bass, reduced bass etc." the only difference ive noticed in the bass section with different power rated receivers is more dynamics, lower powered receivers at high volumes seem to sound "compressed" and "strained" when heavy LFE or bass content in music such as kick drums etc come in.

I'm an electrical engineer. I know what amps can and can not do. The problem is, right now my ears aren't agreeing with my brain. Unlike my buddy (also an EE) who's auditioning all of these amps, I'm still skeptical, and am more or less hell bent on proving my ears wrong, hence the need for the switchbox.

 

[Davemcc]

You can have a high sensitivity speaker that is still difficult to drive due to impedance and what frequencies they are playing. Sensitivity rating does not account for your room and doesn't actually tell you what kind of load it will present to the amp. My speakers are 91dB but are also 4 Ohm making them a tougher load.

I recall from way back the discussion on impedance curves and also a discussion on the RTi impedance...might have been the same thread. The speakers I'm referring to where I heard a difference were like 4 ohm 86db. I only found any difference at loud volume comparing a Macintosh amp against a Denon 2307, mid-line - not the greatest amp section. Even then, it was not a night and day difference but enough to make me invest, given my listening habits and expectations.

If the receiver has a decent amp section, it should perform well with these Polk speakers unless the impedance curve is totally whacked or the nominal impedance rating is grossly inaccurate. The only sure way to tell if it's an audible difference in this case is to plug in an amp and have the listener listen.

 

[Ron Temple]

I recall from way back the discussion on impedance curves and also a discussion on the RTi impedance...might have been the same thread. The speakers I'm referring to where I heard a difference were like 4 ohm 86db. I only found any difference at loud volume comparing a Macintosh amp against a Denon 2307, mid-line - not the greatest amp section. Even then, it was not a night and day difference but enough to make me invest, given my listening habits and expectations.

If the receiver has a decent amp section, it should perform well with these Polk speakers unless the impedance curve is totally whacked or the nominal impedance rating is grossly inaccurate. The only sure way to tell if it's an audible difference in this case is to plug in an amp and have the listener listen.

I'm more than a little familiar with Polks and the RTis are designed to be driven well with most AVRs. That said, the bass drivers in the 7s and 9s do represent a load, especially the 9s. They have some impedence drops below 4 ohms and if you want them to be their dynamic best, then give them power. I don't recall anyone that puts an amp on them not remarking that it makes a large difference.

As far as sound quality improvement with separate amplification, I'm in the camp that says a qualified yes. If your speakers are a load, then certainly...and bass response and sound stage presentation differs with the different designs I've tried. I've done quite a bit of A/Bing (not blind, I don't see the point, in my room, my rig) here to decide which amp or combo of amps works best. What I heard was outstanding sound quality, but some sound more forward, some have better micro detail, some more laid back, soundstage wider, taller or deeper and after many switches, I had to decide what I preferred. I had no preferences going in. I just wanted what sounded best to me. It wasn't an easy decision, but I made it. Trying to drive my speakers with just an AVR is possible, but not optimal.

For speakers that aren't particularly hard to drive, I still mostly hear praises and bass response is usually one the first categories mentioned. I have no reason to doubt this. I bought some older Polk LS90s awhile back. They are a line array, I believe, but not difficult to drive. I auditioned them on an HK635. If I hadn't known anything about those speakers, I would have left them. The sounded nice and balanced, but slightly anemic. When I brought them home and put them in my rig, the difference was staggering. Those puppies really dug deep in the bass and hit hard which they are noted for. These were TOTL in their day, but I wouldn't be totally shocked if the M70s didn't improve as well.

 

[Pyrrho]

for awhile i've been considering adding an external amplifier to my setup but haven't really decided if it's worth it or not. i am an "output junkie" (as Seth=L puts it.) but i have never really driven my Marantz into clipping or anything like that. are there other benefits besides just have more power? another thing that's making me more inclined to add one is that im running the LFE and bass through my fronts.

The ONLY improvement possible with any decent gear is increased power. (This is related to impedance, as what matters is the power capability into the exact impedance of your particular speakers, not the 8 ohm rating.) But some audiophile brands give crap performance that screw up the frequency response (or some other quality, like some type of distortion, etc.), and so they will give you a different sound than a competently made receiver (or other amplifier):

http://www.stereophile.com/content/wavac-sh-833-monoblock-power-amplifier-measurements

If your current receiver is capable of driving your speakers as loud as you want with clarity, there is no reason to buy a separate amplifier, unless, of course, you want to buy some piece of crap like what you will find at the link above, or you like spending money on gear that makes no audible difference at all.

 

[Pyrrho]

I keep trying to tell myself that there's no difference, but a friend brought over a couple different amps that he was in the process of auditioning. First was a McIntosh MC302, the other a Class D Cherry amp. In both cases, I seemed to hear a very noticeable difference between the external amp and my receiver (NAD T742), most specifically in the quality of the bass response.

I'm still not convinced that what I hear is a legit difference and not just a placebo, so when I get time I'm going to rig up a relay switch box so that I can level match then toggle back and forth. My NAD, though only rated at around 50 or 60 watts per channel, has been measured to put out close to 150 with just 2 channels driven, so I'm confident that the NAD is providing adequate unclipped volume levels... which just leaves sound quality. I've always stood on the assumption that amps sound the same, but it seems that now I might be standing on shaky ground.

If you did not precisely level match the outputs of the amplifiers (you would need test equipment to do this), almost certainly you were listening to them all at slightly different volumes. This is a problem, because human hearing is not linear, and a slight difference in volume is subjectively perceived as a tonal difference. This is why they put "loudness compensation" controls on many receivers and preamplifiers of the past, to be able to keep the subjective impression of the tone more like it should be when playing things relatively softly, by boosting the bass, and often the treble, when the circuit is engaged. Basically, the slightly louder one will appear to have more bass, and also somewhat more treble [additionally, one will be able to hear more details (because it is louder, one hears more details)]. You can test this aspect of human hearing for yourself, by playing bass heavy music, and slowly turning down the volume control. The bass will appear to diminish faster than the midrange. But it is due to the imperfections of human hearing, not your gear.

So, unless you precisely level matched the different gear, you probably should subjectively hear a difference, due to the fact that they are almost certainly not outputting the exact same level.

People start believing all sorts of nonsense due to human limitations, but the smarter ones learn about these matters and so they don't get suckered as much. The dumbasses just "trust their ears" and disengage their brains.

You are on solid ground believing that all amplifiers that are decent quality and operating within their limits and are properly functioning and are set at precisely the same level will sound the same. Of course, some gear is crap; here is what $350,000 will get you:

http://www.stereophile.com/content/wavac-sh-833-monoblock-power-amplifier-measurements

 

[jinjuku]

For speakers that aren't particularly hard to drive, I still mostly hear praises and bass response is usually one the first categories mentioned. I have no reason to doubt this. I bought some older Polk LS90s awhile back. They are a line array, I believe, but not difficult to drive. I auditioned them on an HK635. If I hadn't known anything about those speakers, I would have left them. The sounded nice and balanced, but slightly anemic. When I brought them home and put them in my rig, the difference was staggering. Those puppies really dug deep in the bass and hit hard which they are noted for. These were TOTL in their day, but I wouldn't be totally shocked if the M70s didn't improve as well.

I would agree. Bass response and mid bass will be the two things most people hear immediately when putting in a proper power section. You don't hear of too many tweeters that will take 500 watts RMS now

Most amps will also have a better dampening rate which results in much better transducer control (usually 400hz and down).

I like having an amp that I can throw almost any speaker on and know it will be driven properly. I have been through more speakers while my electronics stay the same.

What do you think of the guys that recommend such and such amp for taming bright speakers vs either not buying bright speakers in the first place of padding down the tweater with a few bucks x-over mod. That one always gets me: Lets use a $900 2 channel amp as EQ.