yes sorry
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Am I wasting money? AVR recommendations.
- Thread starter HifiLover
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I can't believe I'm saying this, but I'm strongly considering one of these two companies. As stated before I like to hold onto my equipment for a long time. Seeing how these two companies have such a huge following makes me feel better about considering them. Even if I don't really get a deal on them, it looks like they could perform better than the McIntosh or just as good for a cheaper price. Right now I'm trying to research both companies and their products.I read your earlier post about reading the ASR reviews. If so, did you note the high quality of the Hypex Ncore Class D amps? They have superior bench measurements and tested reliability second to none. They are also much smaller, lighter and run cooler than other amps. Check out Buckeye amps or Nord amps. Very reasonably priced.
Buckeye Amps
Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!www.buckeyeamp.com
I second using a Denon AVR with Pre-Outs for your LCR and using the internal amps for your surrounds and atmos speakers.
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Nord Acoustics supply Hypex Amplifier NCore NC500, NCx500, NC1200, Purifi Amplifier 1ET400A, 1ET7040SA. Hand built using discrete op amps and voltage regulators, Worldwide delivery.nordacoustics.co.uk
If you read through Arcam owner’s forums you will see lots of bugs and iterative firmware fixes over and over.
Also reading through Amir’s reviews you will often see caveats of “likely inaudible” meaning the extremes of SINAD and distortion will be certainly limited by your speakers and human ears. So buy for features and reliability.
techsamurai
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I'm really curious to hear how it augments your system.
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- #44
Thank you for the post! I read it and was pretty impressed.
Figured you did, no worries. Some amps do have pass through, but it’s rare
If you go with Nord they have RCA and XLR inputs plus they offer a $10 add on option that takes care of import duty fees and also gives you access to a US repair center for warranty repairs. I also note you can now extend your warranty to five years for a fee as well. This is new. At the time I bought mine the US companies were very backordered hence why I bought overseas. I have only heard and read good things about Buckeye. I do like the option of having both RCA and XLR inputs. I have used both on my multi8 NC252 now that I transitioned to XLR separates. Just flip a switch.
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I will be too if I end up doing it. Which, right now I'm very close to saying yes. Can I/should I bi-amp the speakers through the amplifier? Somebody posted a 6-channel amp from Buckeye amps. Or would it not matter at that point? 200 watts is a lot of power for the 702 speakers.
Power is a cheap increase for a Class D. Just order a bigger amp. Instead of getting a NC252 get a NC502
Buckeye Amps
Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!
ban25
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I don't recommend bi-amping the Purifi modules, especially at such low impedance. You are already looking at 425 WPC @ 4ohms on the 3-channel Buckeye amp. Gene at Audioholics strongly advised against bi-amping on the NAD M23 unless the speakers were strictly 8ohms.
Class D are more efficient - therefore they produce less heat...Below link is from Audioholics string started by a knowledgeable member there and here. It is in support of Class D tech and presents a nice summary of attributes. Regarding longevity Class D amps do not produce much heat at all. Heat takes a toll on electronics.
Class D power amplifiers
Last time I shopped for the most transparent speakers I could find in the below $10,000 range I found them in a store in Toronto that powered the speakers with, surprisingly, class D amplifiers. In the end I bought the speakers without requesting them to try driving the speakers with my kind of...forums.audioholics.com
Some Class D come with both RCA and XLR outputs. Nord audio is one of them.
But as a result designers aren't as particular about heatsinking, which can result in hotspots and unreliability.
Like any amp that heat will be in direct proportion to the load... hence low impedance speakers which require high current, will generate more heat than "standard 8ohm" speakers.
Most people won't have difficult speakers, they tend to be the exception rather than the rule... so the question of reliability, has to also refer to the use of the amps, their design (how thorough the heatsinking / cooling / active cooling is), and the speakers connected to them.
Looking at how most of the Hypex and Purifi modules are made and mounted, my concern with regards to long term reliability remains.
Has anyone taken FLIR photos of something like an ET400 under load (eg: after 1 hr driving 5W into an 8ohm load...)?
In some cases (from my own experience) Bi Amping is a way to get more out of multiple power constrained amps...
eg: if you have 2 x 100W amps - and difficult to drive speakers (low impedance), dedicating one amp to the "difficult" part of the speaker (usually the bass, but not necessarily!) will mean that you have more total current available, and that should the lower frequencies reach their limit at the amp level, it won't impact the quality of the sound for the rest of the speaker (ie: distortion might increase on the bass, but the mids and highs would be unaffected, whereas if it was a single amp reaching its limits, the distortion generated by reaching its limits in the bass, would affect ALL frequencies being handled by the amp...)
In my case - I found that with lower powered amps, I felt that the sound was marginally smoother when bi-amping - not a huge difference, and possibly and imaginary one.
When I bi-amped with the Crown XLS2500 amps - I honestly could not tell the difference between biamp and single amp.... but the XLS2500 has 440W@8ohm and 1200W@2ohm.
For difficult speakers, the limits are likely to be not the "power output" (most amps don't provide ratings below 4 ohm so it is hard to tell what the power rating is anyway!) - but the limits of the power supply - the current required when the impedance goes low can be massive.
Dual amps, implies dual power supplies, so bi-amping lifts the total current capacity of your system... whether that current is allocated efficiently is then a different question... but that is one of the main reasons why bi-amping (with proper X-Over before the amps!) provides benefits for some speakers.
Your first sentence states a fact. The rest regarding Class D heat and reliability is speculation devoid of any references.
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techsamurai
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You can bi-amp your left and right using your current AVR and see if you like it. You just need the same length cable that you already have. A lot of people say it doesn't make a difference but then you have several reviewers who listen to new gear all the time and they can tell the difference immediately.
Obviously amplifying with more power and a better amp will yield better results.
You are the only one who can decide if it sounds better or worse and you've spent good money on your speakers and amp. It's the easiest test to run.
You may need to re-run audyssey (just fyi - you'll have to do it with the new amp as well).
You probably have your own playlist but here are some tracks in case you want to test them out.
For bass, I use U96's Das Boot DJ Mellow Mix (start of song around 1 minute and from 5:30 minute on). It's literally a bass demo with very fast high frequencies in the mix which if the binding posts. Play it loud and marvel at your speaker's texture in the bass.
Also try Chiara Cavalli's Il Mondo (one of my favorite songs) for vocals and Norah Jones' I gotta see you Again. If you like electronica, Kitaro's Mangekyou from the Album Ki should transport you to another universe.
The Class D modules typically have an aluminium heatsink plate on one side, which is intended to be screwed to the case base - and that is the be all and end all of their heatsink...
That isn't speculation, it is an observation of the modules available from Hypex, Purifi, and ICE.
Amirm reviewed the AIYIMA A07 amp, and took some thermal imaging photos and measurements:
AIYIMA A07 TPA3255 Tear Down
This is a teardown of the AIYIMA A07 TPA3255 Class D Amplifier I just reviewed. I gave it high marks for very low distortion at extremely low budget price. Question was raised on the revision of the board and thermal characteristics of the unit so here we are. I was very pleased to see the...
www.audiosciencereview.com
Here is the thermal image taken after running for 6min @20W
Quotes from that review:
"I let the amp run for about 6 minutes driving 20 watts x 2 into 4 ohm load. The heatsink was too hot to touch and temp kept climbing:
TI specs the chip at 90% efficiency at max power. At 20 watts, it is running around 80% efficient so is producing 8 watts of heat into that little heatsink. With no vent or circulation, I would not deploy this amp for continuous high power use. The junction temp is rated quite high at 150 degrees C though so it is a tough little chip to kill. It has a thermal shutdown of 155 degree C so if it does that, you best not push it remotely that hard.
The two aforementioned electrolytic caps are sitting pretty close to that heatsink. If they not nichicons, they may go first."
This is not an atypical example of a class D design.
What I would like to see, is proper heavy duty heatsinks like on any Class AB or even more so Class A design.
Wherever chips are getting as hot as the Aiyima Amirm reviewed did, and the boards are densely packed with capacitors nearby (like any of the afforementioned modules!) - that heat will reduce the life of both the power chips involved and of the capacitors (and other components) nearby.
Is it more efficient than an equivalent Class AB amp - absolutely - but no one in their right mind would place the power circuits right next to capacitors, and without substantial heatsinks on a class ab design - yet that sort of practice is par for the course on class D.
I remain unconvinced as to the long term lifetime of most of these class-D designs - based on "first principles"
There is a lengthy thread here on ASR on the topic of Class-D reliability...
Class D amp long term reliability
Hi, Looking for 2 channel amp to play a few hours 3-4 days a week. Would like to keep it for the next 10-15 years. Are class D amps today reliable enough to last that long without issues? Or should I go with AB amp? Don't really care one way or the other, but obviously my choice would be...
www.audiosciencereview.com
also specific issues with Hypex NC252MP mentioned here:
Class D amp long term reliability
Yes, I have a high resolution scan of the board. Probably too big to attached. PM me if you like. It's just not worth bothering with to be honest. IMO, there's too much that is wrong for long term reliability. I don't think I've ever seen a commercial product with such poor heat producing...
www.audiosciencereview.com
And these appear to point to precisely the type of design issues I am concerned about and mentioned above.
Here is another set of measurements...
Review and Measurements of Hypex NC400 DIY Amp
I believe hypex goes into standby, so possibly different in this case. There is a standby toggle available, but I have it wired so when it's powered, it's on; I bet most DIYers do the same thing. Instead, I use a power sequencer that turns outlets on after I hit power on my remote.
www.audiosciencereview.com
This is the SMPS1200 power supply used with many of these modules, based on the same design methods...
"Here is an image of a SMPS1200 just before it went into shutdown.
123 degrees celcius on the wire and 96 degrees on the bobbin. The closest capacitors are somewhere around 70 degrees (i dont have the exact reading)"
"Here is an image of a NC500 module after pretty hard load of about 200W without active cooling and abient temperature of 35 degrees
Coil wires are 98 degrees, coil bobbin is 86 degrees and the circuit board between the row of capacitors to the right is 74 degrees. The capacitors closest to the coil are a bit warmer and maybe close to 80 degrees."
This is not a set of temperatures at which you want equipment you want to own for decades, to be running - at these kinds of temperatures, lifetimes are limited.
As a contrasting example.... sets of Quad amps have been known to run for months in speaker short circuit conditions (at BBC studios).... they didn't stop working, they got a bit warm - and when the wiring flaw was resolved, months later... they just cooled down and continued working as per normal.
Their specifications state "unconditionally stable under ANY load"... and indeed that appeared to be the case.
Their specifications state "unconditionally stable under ANY load"... and indeed that appeared to be the case.
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I haven't used FLIR on my VTV Purifi but it barely even got more than room temp anywhere on the case at any volume, slightly warmer when idle vs high volume. The 3 ch Buckeye Purifi is slightly warmer at idle but barely wam vs when the amp is off. I can't imagine the Purifi modules suffering from prolonged high heat, based on my 2 amps with these modules.
Welcome @HifiLover !
I have been a Denon and McIntosh owner for many years. Currently have a Denon AVR-X4800H that is with Amir who has tested it for Review here at the ASR Forum. My old AVR was a Denon which I used with McIntosh Amps for the Mains and Rear Speaker for 5.1 Home Theater. I will upgrade to a 7.3.4 and will use the McIntosh Amps along with the AVR Amps for the Atmos speakers. I use Series-S REL Subs for Front Left & Right and will be adding a Rear Sub, possibly 2 for SR & SL. I Drive Kef Reference Speakers that have been flawless with the Set-up. I've owned this setup, or a version of it for over 25 years. Very reliable and consistently impressive for me, totally happy with the investment. Looking forward to adding the Denon X4800H to replace my AVR-5600 Denon which has become obsolete with today's HDMI and other add-on features for Room Equalization. The value of the X4800H for me is it's Japan built and believed to be a better performer than the 3800. The Review for 4800 is due to release on ASR this week,
Given your shoes, I would go the 4800 and the McIntosh. Both of these points in my circumspect, are in agreement of your original inclination of choice for McIntosh and Denon, and my preference based on many years of satisfaction with both brands. Good Luck and welcome!
It is worth noting that the FLIR images above, are under extreme conditions - the power supply was just before it shut down to self protect, and the NC500 is running at 200W hard load....
Still I look askance at tightly packed components on small circuit boards, which under load, can get seriously hot, and are connected to little or no heatsinking / air cooling systems. Possibly excess sensitivity due to having had two AVR's fail due to heat issues ... but then my Quad power amps never get more than warm even under the heaviest loads....
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