Need advice for how to best use 2 Aiyima A07 amps

[Joe’s Apartment]

Methinks you've been reading the cool-aid.

I drink my own kool-Aid and it hasn’t killed me yet! Lol. I don’t discount out of hand anyone’s experiences with their audio equipment. I’m sure their setup would sound quite different in my room anyway, so I still take their opinions with a grain of salt- and the rest is just a matter of adding or removing color to the signal to suite one’s preferences. You can achieve this by purchasing speakers with specific sound signatures you like or adding eq to a neutral sounding speaker. To each his own.

 

[Chrispy]

“Offering 250w into 4ohms ALL channels driven, our 2ch NC252MP option is the perfect stereo companion for high sensitivity speakers”

Curious why they say it’s perfect for high sensitivity speakers? Is it not able to drive lower sensitivity speakers well?

Because it's not a higher power amp perhaps....

 

[Chrispy]

I drink my own kool-Aid and it hasn’t killed me yet! Lol. I don’t discount out of hand anyone’s experiences with their audio equipment. I’m sure their setup would sound quite different in my room anyway, so I still take their opinions with a grain of salt- and the rest is just a matter of adding or removing color to the signal to suite one’s preferences. You can achieve this by purchasing speakers with specific sound signatures you like or adding eq to a neutral sounding speaker. To each his own.

Just that comparing the electronics takes a bit more care to discern what's actually going on. The attribution by amp class was more what I was after, tho.

 

[Joe’s Apartment]

It's just sales banter.

It comes across as discouraging those with more power hungry speakers from buying imo.

 

[Doodski]

It comes across as discouraging those with more power hungry speakers from buying imo.

Well. The next model up from Buckeye Amps is $749 and has a lot more power output for those that dare.

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

 

[Joe’s Apartment]

By your description, my guess is what you are hearing is your amp running out of power and the distortion increasing. Is that maybe why you hesitate to crank it? I sure think so. Amps running out of power sound really really bad.

I have a Class D amp with super SINAD that sounds awesome, so do the Bryston A/B amps which also have lower but still great performance, and so does the Yamaha CA-2010 that has a Class A mode. All of these awesome amps sound like crap when I run them out of power and clip them. I also had a Topping PA5 that sounded great for a few days before it broke, I never clipped it but that would be one way to make it sound bad for sure.

Side note... here is how bad our brains and ears are: I believe I can hear the difference between the Bryston A/B and the Class D when driven to clipping, but that's because the Brystons have red clipping LEDs so I think it sounds harsher. Would need to ABX to tell which actually sounds worse! But the thing is, distorting amps sound bad.

So, yeah. Save up and buy a nice amp with 100 - 200 WPC. The definition of nice is pretty broad, but has certain specific criteria like reliability, stability, serviceability, and usability... And SINAD.

Actually, I’ve never really “cranked” it. I’m sure it gets plenty loud before producing the kind of distortion you’re describing. The Polk R200s have the same 86dB sensitivity but a nominal impedance of 3.8ohms so they’re given more watts at the same volume and sound a bit louder than the JBLs but are not fatiguing at all in the upper frequencies. I mean, horn loaded compression tweeters are known to sound brighter than silk domes but I was surprised that the JBLs were night fatiguing at all with a meager 50watt hybrid tube amp. My ears do not deceive me as I am sensitive to high frequencies. I’ve experienced the same thing with countless iem earphones as well. Some are very shrill in the upper registers.

 

[Doodski]

horn loaded compression tweeters are known to sound brighter than silk domes

Anybody could say that or similar with intention about any domes. It simply does not hold water as a rational thought. I've heard silk domes be called out for being snappy and sharp so...

 

[Joe’s Apartment]

Well. The next model up from Buckeye Amps is $749 and has a lot more power output for those that dare.

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

Ha! It could be marketing indeed to get you to buy the more expensive amp when the cheaper one would probably drive less sensitive speakers just fine?

 

[phoenixdogfan]

Personally I would bi-amp them, and make sure each amp is getting an upgraded power supply. At least a 40 volt supply, with a 50 volt being preferable. I would not mess with bridging them because if the impedance of your speaker drops much below 4 ohms at any point, the amp will run out of power driving the speaker at that frequency.

 

[Doodski]

Ha! It could be marketing indeed to get you to buy the more expensive amp when the cheaper one would probably drive less sensitive speakers just fine?

Could be. The end of day reality for Buckeye Amps is they offer the best amps for the best price and features. It's good stuff for a good deal.

 

[Chrispy]

Ha! It could be marketing indeed to get you to buy the more expensive amp when the cheaper one would probably drive less sensitive speakers just fine?

They'll both drive the speakers just fine, it's more thinking that you can discern the very minute measurable difference in distortion/noise between them. More about power than small differences in distortion/noise.

 

[Doodski]

They'll both drive the speakers just fine, it's more thinking that you can discern the very minute measurable difference in distortion/noise between them. More about power than small differences in distortion/noise.

For me I would spend the extra little bit and get the big one for $749. It's not much more and one gets their money's worth for sure with the upgrade.

 

[Joe’s Apartment]

Anybody could say that or similar with intention about any domes. It simply does not hold water as a rational thought. I've heard silk domes be called out for being snappy and sharp so...

True, not all silk dome tweeters fit the “smoother” mold just like some titanium domes can sound not so “metallic” but more often than not… it’s generally the case. Indeed, I’ve heard a few shrill sounding silk dome tweeters but many more that sounded rolled off. The horn just amplifies the highs and can sound shouty as a result.

 

[Chrispy]

For me I would spend the extra little bit and get the big one for $749. It's not much more and one gets their money's worth for sure with the upgrade.

Oh yeah for that price difference definitely go for the more powerful one, was thinking more of the difference between Hypex and Purifi modules....

 

[Joe’s Apartment]

Here’s a question for anyone interested: If there’s no discernible difference between the different classes of amps sonically, why choose a class D over a class A or A/B? Would the deciding factor be over efficiency, rated power, performance to price ratio, THD, signal to noise ratio? None of these should sound better if made to the highest standards so why choose one over the other?

 

[Doodski]

Here’s a question for anyone interested: If there’s no discernible difference between the different classes of amps sonically, why choose a class D over a class A or A/B? Would the deciding factor be over efficiency, rated power, performance to price ratio, THD, signal to noise ratio? None of these should sound better if made to the highest standards so why choose one over the other?

Class D will lower your power bill a bit. They are that more efficient. They are not hot running so they won't heat the house in hot environments.

 

[deadwood83]

I think the kool-aid is strong. Tried my EL84 amp on my friend;s studio 590s (92db/W/1m) and it had PLENTY of volume and that thing puts out like... 2 watts before distortion goes above .5%. I think his room is ~20m^2?


HEadroom makes basically 0% difference in sound unless you're trying to drive woofers way below resonant. I threw thousands of dollars at my stereo HT system before I tried room correction / measured EQ. It made more difference than my pocketbook.

If you are really curious then set a test tone of ~150hz as loud as you can stand. Measure the RMS voltage at the amp. I = Vrms / Z (~4 ohms at 150Hz). At that same frequency, the JBL 530 measures about -10Degrees or -.17rad. power factor = cos(phi) = cos(-.17) = .999. Basically a pure resistive load at that frequency where the impedance is lowest.

5A of power in, let's just ball-park 80% efficiency between DC input and amplifier output (even though over 10-20W should be closer to 90% per TI's datasheets) we can say that max current should not exceed 4A, throw that into the equation Watts = Amps * Vrms * power factor. Working backwards we get 55W / (4A * .999pf) = Vrms. If you measure under 14Vrms then you aren't clipping and any deficiency you note is in your room or in your head.


And oh hey look, the chip's specs for a 6-Ohm nominal speaker almost exactly match what Amir measured.

If we pretend that you are hitting clipping and sit 3m away from the speakers, you should still be hitting 97dB. Guess what? OSHA studies show that an exposure to 97dB for more than 30 minutes will cause irreversible and permanent hearing damage. (full document: https://www.cdc.gov/niosh/docs/98-126/)

Do you listen at nightclub levels? Louder than your average Jazz concert?

Do your neighbors complain that you music is literally louder than a jackhammer at 50 feet?

If we pretend you are 20 feet away, the peak SPL only drops to 94dB. You said it's not a huge room. You probably don't ever exceed 10-20W.


"But some reviewers said XYZ sounds more lush and immersive with more breadth and dynamics" Sure, I can also say that I had a threesome with Olivia Wilde and Natalie Portman in 2010. ¯\_(ツ)_/¯

 

[Chrispy]

Here’s a question for anyone interested: If there’s no discernible difference between the different classes of amps sonically, why choose a class D over a class A or A/B? Would the deciding factor be over efficiency, rated power, performance to price ratio, THD, signal to noise ratio? None of these should sound better if made to the highest standards so why choose one over the other?

Cost, weight, efficiency, form factor.....

 

[Joe’s Apartment]

I think the kool-aid is strong. Tried my EL84 amp on my friend;s studio 590s (92db/W/1m) and it had PLENTY of volume and that thing puts out like... 2 watts before distortion goes above .5%. I think his room is ~20m^2?


HEadroom makes basically 0% difference in sound unless you're trying to drive woofers way below resonant. I threw thousands of dollars at my stereo HT system before I tried room correction / measured EQ. It made more difference than my pocketbook.

If you are really curious then set a test tone of ~150hz as loud as you can stand. Measure the RMS voltage at the amp. I = Vrms / Z (~4 ohms at 150Hz). At that same frequency, the JBL 530 measures about -10Degrees or -.17rad. power factor = cos(phi) = cos(-.17) = .999. Basically a pure resistive load at that frequency where the impedance is lowest.

View attachment 242073



5A of power in, let's just ball-park 80% efficiency between DC input and amplifier output (even though over 10-20W should be closer to 90% per TI's datasheets) we can say that max current should not exceed 4A, throw that into the equation Watts = Amps * Vrms * power factor. Working backwards we get 55W / (4A * .999pf) = Vrms. If you measure under 14Vrms then you aren't clipping and any deficiency you note is in your room or in your head.


And oh hey look, the chip's specs for a 6-Ohm nominal speaker almost exactly match what Amir measured.

View attachment 242074

If we pretend that you are hitting clipping and sit 3m away from the speakers, you should still be hitting 97dB. Guess what? OSHA studies show that an exposure to 97dB for more than 30 minutes will cause irreversible and permanent hearing damage. (full document: https://www.cdc.gov/niosh/docs/98-126/)

Do you listen at nightclub levels? Louder than your average Jazz concert?
View attachment 242076
Do your neighbors complain that you music is literally louder than a jackhammer at 50 feet?

View attachment 242077

If we pretend you are 20 feet away, the peak SPL only drops to 94dB. You said it's not a huge room. You probably don't ever exceed 10-20W.


"But some reviewers said XYZ sounds more lush and immersive with more breadth and dynamics" Sure, I can also say that I had a threesome with Olivia Wilde and Natalie Portman in 2010. ¯\_(ツ)_/¯

Are you talking to me? If you are, I never said I pushed my amp to clipping. Like I said, it gets plenty loud but perhaps they would exhibit the sibilance with a more powerful amp cause my room sucks. All I know is the Polks don’t have that issue and neither so my Sonys. It could be due to the huge waveguides but then again, they aren’t sibilant at all when powered by my $200 50watt hybrid tube amp. I guess that’s impossible in your book.

 

[Doodski]

sibilance

How do we know if sibilance is supposed to be heard or not? We don't know. We assume if it's there that it's the speakers fault. Maybe with some soundtracks the sibilance is a natural part of let's say, "Her" voice.