[chas]

For those of you that have added an external amplifier to your receiver...what are your opinions on the effect on performance in your system? I've read various posts on several forums by owners, and conclusions range from "no real difference" to "night and day" improvements.

If you've added an amp to your receiver I'd appreciate some thoughts. Please include as much detail as possible...model of receiver, amplifier, speakers, etc.

Thanks.

 

[tonyvdb]

I added an amp to my main L-R speakers and there was not really a "noticable" difference in sound but my receiver runs alot cooler now and I have mutch more headroom on the amp for the mains if I push it I still dont even show it outputting more than half its maximum level.

 

[tcarcio]

Hi Chas, I recently decided to go with outboard amplification and I quickly realized that the amps I was looking at were just out of my price range. I was told about useing pro amps instead of dedicated home theater amps to save some money. I run a 7.1 system with my Avr being the Pioneer Elite Vsx-81txv which I found adaquit but I wanted more headroom. I read up on alot of amps and talked to many people on different forums and decided to go with Crown. I run my mains on the crown xls-402d, which is 450w a channel at 8ohms, my surrounds on the crown cts-600 which are 300w a channel at 8ohms, my center on a Jbl mp-200 which is 160w a channel at 8ohms, and my dual subs on a behringer ep-2500 which is 650w at 4ohms. Although these amps have cooling fans that can be noisy fan mods are fairly easy and solve the problem. So I use my Pioneer as a pre-amp and the system works well. My first impression was astonishment at the spl that I was able to achieve that bordered on scary as I did not even attempt to max out the amps due to the fear of damaging not only my equipment but my hearing. So my goal of more headroom was not just achieved but surpassed. My movie and music listening is so much better with more clarity and punch than I ever had before and the cost of these amps was much less because I got them all on ebay. I paid a total of $950 for all 5 amps which as you probably know is less than I would have paid for a 7 channel amp of the same power, probably much less. I am very happy I decided to go with outboard amps and probably will never go back to just a stand alone Avr.:yay:

 

[Sonnie]

I have done this in the past, but I never ran just the receiver then added the amps... I started out that way, so I couldn't tell you if there was a difference, although I suspect with the speakers I was running at that time, I doubt it would have been major.

With my new dedicated HT room I am planning to pick up an inexpensive receiver and several Behringer EP2500's... or some inexpensive amps, probably Behringer since I have owned a few, still own one and am familiar with them. However, I will be driving Martin Logan's, which are a difficult load to run on anything with lower power.

I think what speakers you are driving makes a big difference in whether more power will help, which would be the main reason to add outboard amps.

 

[salvasol]

I'm using a Samsom Servo 600, front speaker are two pairs of JBL Stadiums (8 ohms, but I wired them in parallel so they present a 4 ohm load to AVR) :yes:

At the beginning I was using my Yamaha RXV2700 to power all my speakers (7.1), and as Tony mentioned my AVR was running a little hot too (I assume because of the front speakers load), I got the Samson to power the fronts, and now my Yamaha doesn't get to hot.

Another thing I noticed was this: "Gain levels" to achieve reference levels ...when I was using just the Yamaha the gain levels where higher (around +5.0db) and now they're set @ -10db (that's the minimum I can go), I think the sound is cleaner now, and my AVR doesn't have to work to hard like before, and like TC said: "better to have that extra headroom" :yes:

 

[Otto]

I really think it will depend on the speakers and the amps in question. If your speakers are highly sensitive, and you're not running out amps in your receiver out of spec (i.e., they have both enough power, and the impedance of the speakers you are driving complies with what the receiver can drive), you most likely won't find a big difference in sound between your receiver on its own and your receiver feeding an external amp that then drives your speakers.

On the other hand, if you are running out of power with the receiver, an external amp may be of benefit. More importantly, if your receiver can't run the load of the speakers effectively, then you will most definitely benefit from an external amp that can run those speakers appropriately. I ran into this situation when I had a pair of Magnepan MMGs, run by an older Denon receiver with 70 WPC. I don't think the Denon had enough power, and I don't think it liked the ~4 ohm load of the speakers. In that case, adding an Audio Alchemy OM-150 to drive the MMGs made a big difference, in max volume, speaker control and amplifier temperature. The same receiver driving B&W DM602s didn't have those types of problems (I think most of it was related to the impedance of the MMGs).

Are you having any specific problems with your current setup, and what speakers and receiver are you using?

 

[Pinhead-227]

The question I have with regards to this topic, is HOW do you hook the amplifier up to the receiver? Most receivers that I know of don't have low-level outputs (I'm on the bottom end of the value scale). Do the amplifiers in question have speaker-level inputs? I've got a couple of pro amps that I'm not using (Peavey IP-4C and Samson Servo-550) but they've only got low-level inputs. :/

 

[Sonnie]

You will need a receiver with preouts.

When I had my Denon on the ML's... and really tried to crank them, they did not sound right. Upgrading to a better more powerful receiver made a lot of difference. The ML's run as low at 2 ohms though... a very taxing load on amps.

 

[Hakka]

I was using a Denon 3803 to power a 7.1 system (B&W 600s), I watch movies 5 to 10db below reference. I added 2ch and 5ch Rotel amps(RB-1070 + rmb-1075) and noticed a big improvement in dynamics and punch, I found I could turn it up a fair bit louder than before without it sounding harsh.

I've upgraded to a 3808 but never used the internal amps in that.

Hakka.

 

[chas]

Thanks for all the replies...it's an interesting topic (to me anyway!).

I have a decent receiver and easily driven speakers so I have never run into any problems, but always wonder whats on "the other side".

I see quite a few people are using pro-amps with success. Any downsides to these?

 

[Otto]

I have a decent receiver and easily driven speakers so I have never run into any problems, but always wonder whats on "the other side".

Perhaps you know someone that has an amp you can borrow. I can say that tube amps (and preamps, for that matter) can impart their own sound, but that's because of the major design difference.

I see quite a few people are using pro-amps with success. Any downsides to these?

For the most part, a pro amp should work fine. I do believe in subtle differences between amps, but I haven't done any comparisons between pro amps and others to notice any first hand. One common drawback to using a pro amp is that many of them use fans to cool the unit, and the fans can me noisy in a living room or HT environment. I had an EP2500 in my living room and it was very annoying. There are mods, though, to replace the fan and/or reduce its spin rate to the point where it's silent, so it may be a moot point if you're willing to do a little surgery on your amp. Another frequent complaint about using a pro amp is asthetics; many people don't like the look of the pro amp in the rack. On the other hand, I suppose some like the look. I still use the EP2500 to run my IB sub, but it's in my basement, so I can neither hear it nor see it.

 

[salvasol]

I see quite a few people are using pro-amps with success. Any downsides to these?

I agree with Otto ...if you can borrow one you can try it and see if you can notice an improvement.

About the downsides, as Otto mentioned cooling fans, but there's some pro-amp that uses conventional cooling and don't make a lot of noise, depending how you use your amp ...the fan could never turn on (I never hear a noise from mine, either because of the cooling system or because I don't play it to hard).

Aesthetics, I couldn't agree more with Otto, the only two pro-amp I found that I like and can blend with the rest of the system are Samson Servo series or Behringer A500.

Another downside could be the need of an ArtCleanBox to match the levels between consumer and pro products, that's not the case when the pro-amp has RCA connectors, only when you have other kinds of inputs (XLR, 1/4, etc.)