Adding an external amp to an AVR - placebo or am I actually hearing a difference

[Gibsonian]

Avr amps generally stink so guessing your observation is real. I can hear differences in amplifiers. Not a subscriber to the all amps sound the same club

 

[Chrispy]

Avr amps generally stink so guessing your observation is real. I can hear differences in amplifiers. Not a subscriber to the all amps sound the same club

What makes the avr amp "stink"? What is so different between the amps in question here particularly? Your hearing "differences" is based upon what testing with what protocols? That "all amps sound the same" is closer to reality than not, tho.

 

[Gibsonian]

What makes the avr amp "stink"? What is so different between the amps in question here particularly? Your hearing "differences" is based upon what testing with what protocols? That "all amps sound the same" is closer to reality than not, tho.

Design and cost cutting choices made by manufacturers is what make them “stink”. Take a look at AVR amp performance as measured by Amir on this site.

 

[Chrispy]

Design and cost cutting choices made by manufacturers is what make them “stink”. Take a look at AVR amp performance as measured by Amir on this site.

You just need to buy the avr suited to your purpose. AVR amps are still quite sufficient and I still doubt you could be able to tell the difference between that Marantz power amp and the Denon....from the same company and they probably share a good chunk of design and parts in any case, more similar than different. Are there better measuring amps? Sure...audibly different to the extent you imply, no....

 

[Johnkeizer]

I always used to run an external amp fo the front left and right and it did make a difference, despite my av amp being a big yamaha.
Now that the system is in a smaller room I am only running the avr due to space limitations but would put the extra amp in if I could.
I do run 2 identical subs, placed just outside the front left and right so the image is central as despite what marketeers try to tell you, you can’t just put a sub anywhere.
And while I think good measurements are important, I also am convinced from my experience that amps do sound different.

 

[Chrispy]

I always used to run an external amp fo the front left and right and it did make a difference, despite my av amp being a big yamaha.
Now that the system is in a smaller room I am only running the avr due to space limitations but would put the extra amp in if I could.
I do run 2 identical subs, placed just outside the front left and right so the image is central as despite what marketeers try to tell you, you can’t just put a sub anywhere.
And while I think good measurements are important, I also am convinced from my experience that amps do sound different.

I've run a variety of avrs (have 5 on hand now) with and without various power amps for a number of years. Just not my experience that adding a power amp will somehow improve the audio other than for power/impedance handling depending on speakers.

Old saying about subs is they need to be placed where they need to go rather than where perhaps you want them to go....

 

[Roland68]

Hey everyone – greetings from South Africa.

I know this has been asked many times before. I've read through a bunch of threads, but I haven't found a satisfying answer yet. The opinions I'm getting are all over the place, so I'm not sure who to trust.

Here's my setup:

• Denon AVR-X4500H running a 6-speaker configuration
• Fronts: Bentley FS250s (200W, 6Ω, 32Hz–25kHz, 92dB sensitivity)
• Rears & ceilings: nothing fancy
• Sub: SVS SB1000

The system is 99% for music listening. I've calibrated with A1 EVO and usually listen in Neural X (all speakers playing – I know some might consider that sacrilege).

Coming from Logitech Z680s, I was absolutely ecstatic with this setup. I never knew music could sound this good.

But I got curious: would an external amp help? Many people say that if it's not distorting, an external amp won't make a difference.

I figured the only way to know was to test it myself. So I bought a second-hand Marantz MM7025 (140W x 2)
I bi-amped it to my fronts – the amp handles the bass, while the AVR still covers mids and tweeters.
My plan was to try it out, and if the difference wasn't significant, sell the amp and upgrade something else (like a second sub).

I was expecting a small improvement. But honestly, I feel like I'm hearing a substantial difference.

It seems like my AVR was holding the FS250s back – I definitely wasn't getting their full potential. The fronts felt throttled before. Now the soundstage feels wider, more "effortless." And that's saying something, because I was already thrilled with the old sound.

Bass is tighter and better integrated. Even lyrics are clearer – which I really didn't expect. Everything feels like it's been turned up to 11.

After calibrating, I listened to music for five hours straight. Songs I've heard hundreds of times sounded different – better. I could hear audible differences in almost every track. Some lyrics in dynamic songs that I'd long assumed were just inaudible suddenly popped out.

So here's my question: Am I actually hearing a real difference, or is it placebo – all in my head?

I asked this on a local forum and got wildly different answers. Some agreed with my findings. Others said I'm basically full of it – that the amp only adds extra gain, and what I'm hearing is just loudness bias.

I'm hoping for a more scientific answer here. I'm not looking for validation – just a better, more nuanced explanation. If it's just confirmation bias, please tell me straight.

Thanks.

The simplest explanation would be a slight difference in gain/volume between the two amplifiers, which could certainly lead to audible differences and would, of course, also affect the tuning of your speakers.
The easiest way to test this is to swap the connection cables on one side, i.e., the Marantz for midrange/treble and the AV receiver for bass.
Listen to the sound, and then swap the cables on the other side as well, i.e., Marantz for midrange/treble and the AV receiver for bass on both sides. Listen again, and then switch back to the original configuration.
Then let me know what you think.

Another possibility is a common phenomenon. Many Class A/B amplifiers of this size have their best measured values at around 5-10 watts. You may have hit this sweet spot with bi-amping and are now 15-20 points better in terms of noise figures, which would indeed be audible.

A combination of both would amplify the effect even further.

 

[Cbdb2]

1. So, by biamping - the Denon doing the mids, then using the preouts to the Marantz, which then is wired separately to the bass drivers - I'm not effectively getting the combined power of both amps, it's still limited to 140w?

Correct the power is usually limited by the max voltage the amp can put out and that wont change, the only advantage is having more current on demand but you only need that if your speakers impedance drops below 4 ohms and your listening almost full volume. Biamping has little advantage unless your using an active crossover.

 

[Cbdb2]

You may have hit this sweet spot with bi-amping and are now 15-20 points better in terms of noise figures, which would indeed be audible.

Which could be audible. It could also still be below audible level.

 

[EasyC]

Which could be audible. It could also still be below audible level.

Can't say if it's audible (seemed like it ) but when I hooked up a power amp to the pre-outs of my Denon3800, it did run substantially cooler...

 

[Cbdb2]

Yes thx. Thinking more about it there is one power advantage to biamping. Since the actual power the 2 amps put out will be the same as the single amp power, each amp will be putting out less power. They dont put out more total power because there max voltage is the same but they share the current so can source more total current. So they dont get as hot. If your amp is over heating biamping will help but it wont help with voltage clipping.

 

[Chrispy]

Yes thx. Thinking more about it there is one power advantage to biamping. Since the actual power the 2 amps put out will be the same as the single amp power, each amp will be putting out less power. They dont put out more total power because there max voltage is the same but they share the current so can source more total current. So they dont get as hot. If your amp is over heating biamping will help but it wont help with voltage clipping.

That wouldn't be a particularly great difference, tho. More rationalization than something effective....

 

[dualazmak]

Just for your reference, similar discussions are now going on the remote thread;
Sharing a pair of speakers and a subwoofer between a stereo and a multichannel system