Power Amp To Pair With Denon AVR-X3700H (Class AB or D?) (150-200WPC)

[amper42]

I got an AVR X3700H and a Monolith 5x200 a couple of months ago and they work perfectly together. The Monolith is built like a tank and runs very cool, I’m pretty sure the 2x would be the same. That said, there are a lot more amp options in the 2 channel space than in the 5 channel space. I had hoped to get a class D 5x single chassis amp but but could not find a good balance of price and quality. That will probably improve within a year but I didn’t want to wait. For your needs, I’d lean towards the March Audio.

I have the Denon 4700 and the Monolith 7x200 plus an Adcom 5 channel. This combo allows me to setup a 7.2.4 configuration with the Denon 4700 in preamp mode. This setup sounds great! Multi-Channel mode can really open up the sound stage with the right speaker combination and placement. It's like being at a concert.

I purchased the March Audio P452 Purifi based amp and placed it on the fronts as I wanted to try the clean sound everyone raves about with the Purifi. Unfortunately, I found when I use Multi-channel or Auto-3D modes with the lower Purifi 26.5dB gain amp - it's a poor match when Monolith 7x200 drives the other channels. Even if Audyssey level matches the speakers initially, the levels don't stay in sync as volumes change. This difference in gain between the amps is a non-starter. The fronts on the Purifi sound really low at lower levels, it's almost as if they are 50% lower than the channels driven with the Monolith amp.

While the Purifi sounds good by itself on a 2 channel setup, I can't recommend it with a multi-amp (with different gains) home theatre setup - the only exception would be if all your amps were Purifi - and that's an expensive option.

 

[Bear123]

I have a Denon AVR-X3700H on the way and am interested in eventually adding a separate stereo amp to use in a 2.1 setup. I'm powering Ascend Sierra 2-EX (85dB sensitivity). I'm intrigued by the small form factors of class D amps, but interested in what others have used with good results for pairing. Ideally I'd like to stay in the 1200 USD and under mark. Right now, I'm considering the Monolith 2x200 or something like a March Audio Hypex.

Is this a 2 channel *ONLY* setup? If you have or will have a center channel, maybe consider a 3 channel amp. The cost is barely different from 2 channel versions in some instances. For example, $1100 for the Monoprice 2 channel; another $150 gets you three channels.

 

[amper42]

Is this a 2 channel *ONLY* setup? If you have or will have a center channel, maybe consider a 3 channel amp. The cost is barely different from 2 channel versions in some instances. For example, $1100 for the Monoprice 2 channel; another $150 gets you three channels.

I would agree. If you are going to use multiple amps it can cause an issue if they do not all have the same gain. I thought Audyssey could take care of the issue but the variation at different volume levels can make it impossible to keep the non-gain matched amps in sync level wise. If my Adcom dies I'll buy a Monolith 5x200 to match my 7x200. ;-)

 

[CoolHandDuke]

Is this a 2 channel *ONLY* setup? If you have or will have a center channel, maybe consider a 3 channel amp. The cost is barely different from 2 channel versions in some instances. For example, $1100 for the Monoprice 2 channel; another $150 gets you three channels.

It is 2 channel only and don't have plans for a center. My stereo straddles a fireplace, so no real place to put it. I agree the 3 channel is a better bang for buck. Since amps can last for the long haul, I do want it to be robust and somewhat "future proof" in the case I change speakers to something harder to drive or more sensitive. The Sierra 2-EX are not designed to be SPL monsters, but I'm not sure what my future brings as far as floor standers.

 

[BigSweeny]

If you're just using it for 2 channel setup have you done a quick calculation on how much power you actually need to drive the front speakers to see if it's worth your while in even spending the cash?
I don't mean to deflate your bubble or reason for wanting to get an external amp but I just purchased a Audiophonics MPA-250NC (2x250W) to connect to my pre-outs on my Denon AVR-X3600H powering my fronts (Elac DBR62) in a 5.1 setup just to test out how much of a difference it would make vs the Denon powering the speakers. At the levels I would (sanely) go to it's basically inaudible in either 2.1 or 5.1 setup. That's not to say the amp isn't great, it obviously is very transparent, provides a lot of dynamic headroom, and can easily power the fronts at crazy levels but it's not really a noticeable difference. It's just a very transparent power amp.

BTW the amp is compact, runs fairly cool (give it room to breath, mine was inside a unit before and under normal load started getting as warm as my denon), and has a ton of headroom that is audibly transparent. I would highly recommend getting class D and if you're not after 'colouring' the sound but instead making it audibly transparent then there's no really no reason to go with anything but a decent class D amp.

TLDR: Don't get too stuck in the technical stats and buying separates just for the sake of it. Unless you can hear the clipping/distortion on your speakers when your X3700H arrives just save your money and be happy with the good AVR it is.

 

[CoolHandDuke]

If you're just using it for 2 channel setup have you done a quick calculation on how much power you actually need to drive the front speakers to see if it's worth your while in even spending the cash?
I don't mean to deflate your bubble or reason for wanting to get an external amp but I just purchased a Audiophonics MPA-250NC (2x250W) to connect to my pre-outs on my Denon AVR-X3600H powering my fronts (Elac DBR62) in a 5.1 setup just to test out how much of a difference it would make vs the Denon powering the speakers. At the levels I would (sanely) go to it's basically inaudible in either 2.1 or 5.1 setup. That's not to say the amp isn't great, it obviously is very transparent, provides a lot of dynamic headroom, and can easily power the fronts at crazy levels but it's not really a noticeable difference. It's just a very transparent power amp.

BTW the amp is compact, runs fairly cool (give it room to breath, mine was inside a unit before and under normal load started getting as warm as my denon), and has a ton of headroom that is audibly transparent. I would highly recommend getting class D and if you're not after 'colouring' the sound but instead making it audibly transparent then there's no really no reason to go with anything but a decent class D amp.

TLDR: Don't get too stuck in the technical stats and buying separates just for the sake of it. Unless you can hear the clipping/distortion on your speakers when your X3700H arrives just save your money and be happy with the good AVR it is.

You are probably right. My 3700 comes tomorrow, and I'm sure the difference XT32 makes compared to my current XT will be a bigger difference than an external amp will make. Even more so, upgrading my speakers to the Sierras. It's the added headroom and lower noise (even if not very audible with 85dB sensitivity) that appeals to me. Is it wishful thinking that it might also extend the life of the AVR not flexing the internal amps? Lol. The difference 200WPC makes vs the 105 from the 3700 would be a minimal increase in volume, but in my mind, would add headroom during dynamic passages in movies. I've just got that bug that wants to know the difference. It's fun, but also frustrating.

Quick calculator online shows 104 max SPL at my 7.5ft MLP with 105W. Way over anything I'd ever listen at. I'm probably closer to 70-75 at my "spirited" listening. When I have gone closer to reference while watching movies, things do begin to sound harsh. I'm not sure if that's the speaker limitations or amplification problems.

 

[BigSweeny]

You are probably right. My 3700 comes tomorrow, and I'm sure the difference XT32 makes compared to my current XT will be a bigger difference than an external amp will make.

Absolutely, this will be a nice upgrade. I went from XT to XT32 using the Audyssey app (very much recommended) and Ratbuddyssey app to fine tune it to my preferences. It's really nicely balanced with my own preference of a 3db boost to the bass, no room correction above 500hz for my fronts, midrange compensation off, dynamic EQ&Volume off, and boosting up the mid frequencies on the center to make speech more audible.

Even more so, upgrading my speakers to the Sierras. It's the added headroom and lower noise (even if not very audible with 85dB sensitivity) that appeals to me. Is it wishful thinking that it might also extend the life of the AVR not flexing the internal amps? Lol. The difference 200WPC makes vs the 105 from the 3700 would be a minimal increase in volume, but in my mind, would add headroom during dynamic passages in movies. I've just got that bug that wants to know the difference. It's fun, but also frustrating.

Hah! The "bug" was the main reason I went ahead and bought the MPA-250NC just out of curiosity (expensive curiosity!). I would say that making sure the amp has plenty of ventilation/room to breath is far more important than worrying about flexing the internal amps. Yes, you would be taking the load off of the amps but unless you're unlucky with the unit I'd say you'll be upgrading it way before you'd be worrying about internal amp overusage.

With regards to dynamic headroom, I can only go with my previous statement that I can't really tell much of a difference at listening levels before the missus is reaching for the controller to turn the volume down Classical music does maybe sound nicer but it could also be complete placebo that I'm expecting it to sound nicer now that I have the new amp with better dynamics headroom etc.

Quick calculator online shows 104 max SPL at my 7.5ft MLP with 105W. Way over anything I'd ever listen at. I'm probably closer to 70-75 at my "spirited" listening. When I have gone closer to reference while watching movies, things do begin to sound harsh. I'm not sure if that's the speaker limitations or amplification problems.

And herein lies the problem, you won't know unless you can test it thoroughly. Remember that you are changing the amp, and room correction, first so see if the 'harshness' problem goes away. If you're still curious after and have the money to spare then get a good class D amp to satisfy your curiosity but objectively speaking unless you're hearing an issue currently then you'll just plug it in and go "wow, this is the same!"

 

[CoolHandDuke]

Absolutely, this will be a nice upgrade. I went from XT to XT32 using the Audyssey app (very much recommended) and Ratbuddyssey app to fine tune it to my preferences. It's really nicely balanced with my own preference of a 3db boost to the bass, no room correction above 500hz for my fronts, midrange compensation off, dynamic EQ&Volume off, and boosting up the mid frequencies on the center to make speech more audible.



Hah! The "bug" was the main reason I went ahead and bought the MPA-250NC just out of curiosity (expensive curiosity!). I would say that making sure the amp has plenty of ventilation/room to breath is far more important than worrying about flexing the internal amps. Yes, you would be taking the load off of the amps but unless you're unlucky with the unit I'd say you'll be upgrading it way before you'd be worrying about internal amp overusage.

With regards to dynamic headroom, I can only go with my previous statement that I can't really tell much of a difference at listening levels before the missus is reaching for the controller to turn the volume down Classical music does maybe sound nicer but it could also be complete placebo that I'm expecting it to sound nicer now that I have the new amp with better dynamics headroom etc.



And herein lies the problem, you won't know unless you can test it thoroughly. Remember that you are changing the amp, and room correction, first so see if the 'harshness' problem goes away. If you're still curious after and have the money to spare then get a good class D amp to satisfy your curiosity but objectively speaking unless you're hearing an issue currently then you'll just plug it in and go "wow, this is the same!"

That damn bug! I apply room correction just below 300hz and I played with Ratbuddysey, but did something wrong because my REW measurements of subwoofer went crazy after I tried putting in boosts and cuts. I'll probably try again with the 3700.

Yeah, I'll just need to see what difference I hear in the AVR upgrade and go from there. I just want everything to be maximized in a hobby that knows no perfection.

 

[Bear123]

You are probably right. My 3700 comes tomorrow, and I'm sure the difference XT32 makes compared to my current XT will be a bigger difference than an external amp will make. Even more so, upgrading my speakers to the Sierras. It's the added headroom and lower noise (even if not very audible with 85dB sensitivity) that appeals to me. Is it wishful thinking that it might also extend the life of the AVR not flexing the internal amps? Lol. The difference 200WPC makes vs the 105 from the 3700 would be a minimal increase in volume, but in my mind, would add headroom during dynamic passages in movies. I've just got that bug that wants to know the difference. It's fun, but also frustrating.

Quick calculator online shows 104 max SPL at my 7.5ft MLP with 105W. Way over anything I'd ever listen at. I'm probably closer to 70-75 at my "spirited" listening. When I have gone closer to reference while watching movies, things do begin to sound harsh. I'm not sure if that's the speaker limitations or amplification problems.

My guess is that the Denon's internal amps are capable of driving the Sierra 2EX way into the threshold of massive distortion and compression. Just look at the distortion measurements of the Sierra 2. If you were further away, *maybe* the argument could be made for more power, but at 7.5 feet I wouldn't think it would take much power to drive the 2EX to their clean output limits.

If you decide to spring for a nice 3 channel amp, I would love to see REW maximum output/distortion/compression sweeps with the Denon vs the external amp to see if the extra power makes any difference with the signal coming out of the speakers.

In fact, I would think there are at least a handful of members here who have the capability to do just that.

Would be very interesting to see where the rubber meets the road using the 3700's internal amps vs the good external amps.

 

[amper42]

My guess is that the Denon's internal amps are capable of driving the Sierra 2EX way into the threshold of massive distortion and compression. Just look at the distortion measurements of the Sierra 2. If you were further away, *maybe* the argument could be made for more power, but at 7.5 feet I wouldn't think it would take much power to drive the 2EX to their clean output limits.

If you decide to spring for a nice 3 channel amp, I would love to see REW maximum output/distortion/compression sweeps with the Denon vs the external amp to see if the extra power makes any difference with the signal coming out of the speakers.

In fact, I would think there are at least a handful of members here who have the capability to do just that.

Would be very interesting to see where the rubber meets the road using the 3700's internal amps vs the good external amps.

The Denon 3700 amp is fine for normal listening levels. Most don't need to upgrade to external amps, if they're not using all the channels at higher volume levels. But, if you like multi-channel stereo mode or have speakers with lower sensitivity or like to play near reference levels then external amps make a difference. It's not so much what you hear with the external amp but what you don't hear. The extra overhead provided by my Monolith 7X200 keeps the sound clean during peak volume levels as well as normal calm passages. It doesn't care if I setup the 7.2.4 configuration in multi-channel stereo mode and fill the room with thumping crystal clear music from all corners - creating the widest sound stage I have ever experienced. It doesn't clip or distort on rocket launches, bomb blasts or high impact scenes and it does it all without heat issues.

The other accessory I would not want to be without on the Denon 3700 is the $20 AC Infinity MULTIFAN S7. This fan keeps the Denon nice and cool at the lowest speed and runs quieter than any others I tried. Without it my Denon gets quite hot.

The next step up the configuration ladder with the Denon 3700 is using only external amps by setting the receiver up in preamp mode with amp assign. This is an awesome feature the earlier models didn't have. It gives the user the ability to take the receiver to the next level should they desire to do so. Not a requirement but certainly an option. The power configuration options available with preamp mode are unlimited. It offers an upgrade path for trying lots of different power options until your ears are totally satisfied.

 

[kejar31]

My guess is that the Denon's internal amps are capable of driving the Sierra 2EX way into the threshold of massive distortion and compression. Just look at the distortion measurements of the Sierra 2. If you were further away, *maybe* the argument could be made for more power, but at 7.5 feet I wouldn't think it would take much power to drive the 2EX to their clean output limits.

If you decide to spring for a nice 3 channel amp, I would love to see REW maximum output/distortion/compression sweeps with the Denon vs the external amp to see if the extra power makes any difference with the signal coming out of the speakers.

In fact, I would think there are at least a handful of members here who have the capability to do just that.

Would be very interesting to see where the rubber meets the road using the 3700's internal amps vs the good external amps.

I have a Denon AVR-X3400H, Monolith 2 for the front two which I found used for $600 (outlaw audio 5000 for the other 5 channels, with no issues volume matching to the monolith) HTPC with REW and a calibrated mic.. It wouldn't be to hard to pull speakers and measure each.. I doubt you will see much if anything from a distortion change as the speakers have a ton more distortion than either amp especially in room.

Separates come in handy on dynamic shifts especially at lower frequency's where speakers typically dip their impedance.

 

[amper42]

I have a Denon AVR-X3400H, Monolith 2 for the front two which I found used for $600 (outlaw audio 5000 for the other 5 channels, with no issues volume matching to the monolith) HTPC with REW and a calibrated mic.. It wouldn't be to hard to pull speakers and measure each.. I doubt you will see much if anything from a distortion change as the speakers have a ton more distortion than either amp especially in room.

Separates come in handy on dynamic shifts especially at lower frequency's where speakers typically dip their resistance.

Monolith 2x200 offers 28db gain and Outlaw 5000 offers 29db gain. I would imagine the speakers connected to the Outlaw may run a little bit hotter at some volume levels. Audyssey will level match the speakers based on each amps output at the testing level. However, sometimes different amps have a slightly different slope in the output as volume levels change. I was able to easily identify this issue in Multi-Channel Stereo mode while comparing sound levels of speakers connected to different amps at lower volume levels on my Denon 4700.

I noticed the biggest difference between the Purifi March P452 (26.5dB gain) vs the Monolith 7X200 (28dB gain). While Audyssey level matched all speakers, as volume levels decreased the Sierra Towers on the Purifi amp were significantly quieter than when connected to the Monolith 7x200. As a result, I removed the Purifi and went back to using the Monolith for all channels. I found having the same amps on all channels for home theatre removed the possibility of volume inconsistency at various levels.

 

[kejar31]

Monolith 2x200 offers 28db gain and Outlaw 5000 offers 29db gain. I would imagine the speakers connected to the Outlaw may run a little bit hotter at some volume levels. Audyssey will level match the speakers based on each amps output at the testing level. However, sometimes different amps have a slightly different slope in the output as volume levels change. I was able to easily identify this issue in Multi-Channel Stereo mode while comparing sound levels of speakers connected to different amps at lower volume levels on my Denon 4700.

I noticed the biggest difference between the Purifi March P452 (26.5dB gain) vs the Monolith 7X200 (28dB gain). While Audyssey level matched all speakers, as volume levels decreased the Sierra Towers on the Purifi amp were significantly quieter than when connected to the Monolith 7x200. As a result, I removed the Purifi and went back to using the Monolith for all channels. I found having the same amps on all channels for home theatre removed the possibility of volume inconsistency at various levels.

I think this will be easier to test and validate then the previous request

I can go ahead and run some pink noise through REW and validate using the built in SPL meter for volume levels 50, 60 and 70 and see if we have a shift. Will have to wait until after work or at lunch time.

I am just curious because what you describe on the March P452 seems a bit extreme.

 

[TomekNet]

Monolith 2x200 offers 28db gain and Outlaw 5000 offers 29db gain. I would imagine the speakers connected to the Outlaw may run a little bit hotter at some volume levels. Audyssey will level match the speakers based on each amps output at the testing level. However, sometimes different amps have a slightly different slope in the output as volume levels change. I was able to easily identify this issue in Multi-Channel Stereo mode while comparing sound levels of speakers connected to different amps at lower volume levels on my Denon 4700.

I noticed the biggest difference between the Purifi March P452 (26.5dB gain) vs the Monolith 7X200 (28dB gain). While Audyssey level matched all speakers, as volume levels decreased the Sierra Towers on the Purifi amp were significantly quieter than when connected to the Monolith 7x200. As a result, I removed the Purifi and went back to using the Monolith for all channels. I found having the same amps on all channels for home theatre removed the possibility of volume inconsistency at various levels.

I will test this by myself soon with a Purifi amp connected to the fronts and multi-channel Hypex Ncore amp (on delivery) connected to other speakers of my 5.2.2 setup. I really hope the output slopes of those two power amps will be close enough. The difference in gain (28.6 vs 26 dB) will be leveled by the Audyssey, I believe.

 

[amper42]

I will test this by myself soon with a Purifi amp connected to the fronts and multi-channel Hypex Ncore amp (on delivery) connected to other speakers of my 5.2.2 setup. I really hope the output slopes of those two power amps will be close enough. The difference in gain (28.6 vs 26 dB) will be leveled by the Audyssey, I believe.

I didn't really notice the difference until I started playing music in Multi-Channel stereo mode which requires a lower volume level to have a level match with Stereo mode. The Sierra Towers volume was 3 db lower with the Purifi amp than when connected to the Monolith 7x200. It was easy to tell the difference even by ear. I didn't think to check this before as I took it for granted that Audyssey would take care of the volume differences between amps (at all volumes). Boy was I wrong. lol

Once I moved the Sierra Towers back to the Monolith 7x200 and ran Audyssey again it was easy to hear they were once again equal participants in the multi-channel stereo sound stage.

I have been playing "Wating for Dawn" by Sinne Eeg off Qobuz on my system lately and it's one of the best jazz CD's I have heard. Track 5 "Sudden Change of Weather" is playing now. It's jamming!

 

[Rottmannash]

I didn't really notice the difference until I started playing music in Multi-Channel stereo mode which requires a lower volume level to have a level match with Stereo mode. The Sierra Towers volume was 3 db lower with the Purifi amp than when connected to the Monolith 7x200. It was easy to tell the difference even by ear. I didn't think to check this before as I took it for granted that Audyssey would take care of the volume differences between amps (at all volumes). Boy was I wrong. lol

Once I moved the Sierra Towers back to the Monolith 7x200 and ran Audyssey again it was easy to hear they were once again equal participants in the multi-channel stereo sound stage.

I have been playing "Wating for Dawn" by Sinne Eeg off Qobuz on my system lately and it's one of the best jazz CD's I have heard. Track 5 "Sudden Change of Weather" is playing now. It's jamming!

That is one nice track. Thanks for the recommendation.

 

[Rottmannash]

I didn't really notice the difference until I started playing music in Multi-Channel stereo mode which requires a lower volume level to have a level match with Stereo mode. The Sierra Towers volume was 3 db lower with the Purifi amp than when connected to the Monolith 7x200. It was easy to tell the difference even by ear. I didn't think to check this before as I took it for granted that Audyssey would take care of the volume differences between amps (at all volumes). Boy was I wrong. lol

Once I moved the Sierra Towers back to the Monolith 7x200 and ran Audyssey again it was easy to hear they were once again equal participants in the multi-channel stereo sound stage.

I have been playing "Wating for Dawn" by Sinne Eeg off Qobuz on my system lately and it's one of the best jazz CD's I have heard. Track 5 "Sudden Change of Weather" is playing now. It's jamming!

Check out Ashley Henry -
"Beautiful Vinyl Hunter" on Qubuz.

 

[kejar31]

As for the request to check distortion differences as measured by REW from both an external amp (Monolith) and internal Denon amps, here are the results..

This was taken using a mic 1 meter away at tweeter level in my room both from the right speaker.

I did a measurement at 75db and 90 and there was not a discernable difference at least from my eyes

Included are each of the 4 measurements

 

[CoolHandDuke]

Check out Ashley Henry -
"Beautiful Vinyl Hunter" on Qubuz.

What are you guys using to steam Qobuz? I'm thinking of breaking away from Tidal. BubbleUPNP?

 

[CoolHandDuke]

My guess is that the Denon's internal amps are capable of driving the Sierra 2EX way into the threshold of massive distortion and compression. Just look at the distortion measurements of the Sierra 2. If you were further away, *maybe* the argument could be made for more power, but at 7.5 feet I wouldn't think it would take much power to drive the 2EX to their clean output limits.

If you decide to spring for a nice 3 channel amp, I would love to see REW maximum output/distortion/compression sweeps with the Denon vs the external amp to see if the extra power makes any difference with the signal coming out of the speakers.

In fact, I would think there are at least a handful of members here who have the capability to do just that.

Would be very interesting to see where the rubber meets the road using the 3700's internal amps vs the good external amps.

Keep in mind these are the 2EX and not the 2s, but absolutely, 2 way bookshelf speakers are certainly limited in volume. Thankfully that volume is well below my normal listening level. However, the speaker hiss has become audible at times even before the speakers sound heavily distorted. That's what I was hoping an external amp would rectify. I'm new to all this though and I'm just making conjectures off the limited knowledge I have gained on here.