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New world of HiFi with Chinese Class D Amps.

J English said:
Have and use several, with good results. Started with the original Aiyma A04 and A07 amps. Use a SMSL AO100 bluetooth amp in the dining room system; not a ton of power, but perfect for that medium size room where we want soft to moderate volumes. I am currently using the new Fosi BT20A MAX in my bedroom system, perfect for that setup, has two RCA inputs plus Bluetooth. I also use two Aiyima A07 MAX amps as monoblocks in a summertime porch system. I also have the Fosi V3 stereo amp, nice volume control with that one. I also use and love my small Schiit Gjallarhorn amp (class AB) paired with their Saga 2 preamp for my main workroom system.

With my smaller size rooms, multiple systems, and listening at light to moderate volumes, these amps work perfectly. I have established nice relationships with the Aiyima and Fosi audio support folks, they are very responsive to questions and suggestions.

All of the op-amp rolling is unnecessary for good sound, that was more of a marketing ploy. I think these smaller amps are not ideal for speakers that are very demanding or where people want to play continuously loud. For that, the best class D option are Hypex or Purifi amps ($500 and up).
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I got into Schiit myself also. First with Mani 2 and latest Mimir/Lokius/Jotunheim 3.

Op Amps I can hear the difference if the two have a big difference. Some have almost no difference.

I think if you can do few different things like EQ, Op Amps and Bi Amping the high and Low separate you will get a good improvement.

High volume today gets you evicted.))) If you would crank it up like in 80's you would have someone at your door telling you off. People are lot less tolerant today.
 
I have a pair of Fosi V3 monoblocks. Picking up on the earlier somewhat heated discussion on specs, Fosi claims 240 watts into 4 ohms. And they deliver! Fosi Audio V3 Mono Amplifier Review

I'm not a 'numbers always and only' guy but that's pretty impressive. They also sound good.

I recently purchased a Sonogy Black Knight A/AB -- gorgeous amp. Set it up to blind A/B with the Fosi's -- level matched with REW. Switcher was Fosi LC30 with remote for fast switching from the listening position.

I could not hear a difference at the levels I was listening at. I was in a small/medium room (15' x 12') or so, about 10' from the speakers. Maybe in a bigger room driving very hard there would be more of a difference but that's never going to be my situation.
 
P.M.B.66 said:
Compared to your vintage gear Class D sounds very different. More modern sound maybe. Today just as good. But if your ears are custom to older amps it might take few weeks to train your ears to a new sound. This is maybe the biggest hurdle after years of listening vintage amps.
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This is the kind of stuff that really makes me eyeroll . . . . A properly working amp looks like wire with gain . . . amps (well, good ones at least) don't have a "sound" . . . Interactions with thier environment may create variables (damping factor vs. bad cabling, etc.) but that's not really the amp.

To the other guy who asked how much offshore Class D I have owned, the answer is none, but not for the reasons some will likely bleat . . . Firstly, if an item isn't documented, supportable, or serviceable, I won't buy it - no matter the origin. Second, gear with at least some obviously falsified specs is also off my list . . . what else have they lied about? And lastly, I can't recall any offshore cheap stuff (Class D or otherwise) that I have ever heard in any context that sounded better than "marginal" at best, or that had any chance of longevity. Yes, that's my quirk, but note the age of my stuff, and get back to me when any of this no-name brand offshore stuff goes 50 years with no issues . . .
 
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These quality mini amps are great in my experience. Even the cheaply-made Lepai's sounded pretty good, but build quality was quite poor (had several fail after year or two). Fosi, Nobsound, SMSL are all great for what they are. I have Nobsound 2.1 powering my deck Polk speakers with in-ground sub -- the amp is outside in a protective box and has been through sub-zero winters and hot summers for 7 years and still sounds amazing. Have Fosi powering my kitchen 2.1 system, my living room TV 2.1 system, and the 2.1 audio system in a custom built arcade machine. All sound great and have been reliable. I have to agree with @Apreggiator that my Teac AG-H350 mini 5.1 receiver sounds slightly better than the micro amps, but not by much and for the price/size/convenience they are impossible to beat.

P.M.B.66 said:
SMSL I just got their PL20 CD transport. Looks great and wasn't expensive. Very good for the money.
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I have the SMSL PL100 CD Player. I had been looking for a LONG time for CD transport that was tiny and high quality and reasonably priced (most dedicated CD transports are ridiculously priced). The PL100 weighs a ton for as tiny as it is -- the density makes it feel like you are holding a brick!. And it works great. The faceplate graphics on the PL100 are ugly in photos, but it looks great in person. Now they have the PL150 and PL20. I still like the tiny design and layout of the PL100 best, but wish it had just a brushed silver face instead of the graphics. Haven't tried the other CD models, but I'd guess the quality is as good or even better. Hard to believe the quality you get for the price.
 
tadawson said:
.... get back to me when any of this no-name brand offshore stuff goes 50 years with no issues . . .
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Be sure to leave us your contact info!

ouija-board.jpg
 
tadawson said:
Get back to me when any of this no-name brand offshore stuff goes 50 years with no issues . . .
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How about this amp, mounted outside (in a protected box), on this deck, for 7 years of flawless performance driving a pair of Polk Atrium 6's and a passive sub (under the deck).

You can see one of the Atrium 6's in the corner of the handrails in the last pic ..

shopping



p1270989-jpg.2988965



img_0375-jpeg.3685387
 
DesertRatt said:
Is there a particular amp you know of with these protections?
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Most amps have some protections for the speakers built in. Usually you'll hear a relay click a couple seconds after power on, connecting the amp to the speakers once the protection circuit is satisfied that the amp is behaving itself properly - i.e. no major DC offset, no crazy current draw.

The class D amps typically don't use relays, but they have smarter control circuits that monitor the output and will keep power to the output stage off if the amp is misbehaving. And of course, they monitor the amp output while it's playing, too. It protects both the amp from shorts on the output and the speakers from amplifier problems. I don't know if they monitor for things like high frequency oscillations that might destroy tweeters.
 
I have a Wiim Amp Pro and a Wiim Amp Ultra. Both sound great, and you can't beat the built in functionality. I use the Ultra with the Quads and SVS 3000 Micro sub. The sub gives me the lows the Quads can't produce and because the bass management in the amp is configured as a crossover. It keeps the lows out of the Quads allowing them to play everything else louder. And it's all controlled with my Android phone or tablet. Select some music, hit play, and the amp wakes up and starts playing. Within a couple seconds, the sub wakes up and starts playing. A few minutes after the music ends, they both go back to sleep. There are no knobs to twiddle, no switches to flip, no remotes to juggle or clutter up the living room.

Are they going to be usable in 10 years, 20 years? We'll see. If I get 5 years out of them, and they don't destroy my speakers, I won't mind replacing them. The bigger question is whether we will still be streaming music, using wifi or bluetooth in 5 years.
 
DesertRatt said:
Is there a particular amp you know of with these protections?
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Class D or otherwise? In more "traditional" amps and receivers, they were pretty hard to *NOT*nfind. (Anything that stays silent for a moment, and then comes on with a "click" . . . ). Can't say that I have had enough interest in Class D to have paid that much attention . . .

(Thinking about it, though, the way Class D works, is one even capable of DC output or being DC coupled? Might not be a similar risk . . . )
 
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peterp1 said:
How about this amp, mounted outside (in a protected box), on this deck, for 7 years of flawless performance driving a pair of Polk Atrium 6's and a passive sub (under the deck).

You can see one of the Atrium 6's in the corner of the handrails in the last pic ..

shopping



p1270989-jpg.2988965



img_0375-jpeg.3685387
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7 years? Still a virgin . . . :) (And "in a protective box" might as well be indoors . . . cold doesn't bother electronics.)
 
P.M.B.66 said:
Compared to your vintage gear Class D sounds very different. More modern sound maybe. Today just as good. But if your ears are custom to older amps it might take few weeks to train your ears to a new sound. This is maybe the biggest hurdle after years of listening vintage amps.
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Processed? Consider me untrainable.
 
Have been making DIY projects with class D amps for years since TPA3116. The TPA based 3255 amps upp'ed the game a considerable bit and sound great, and they are pretty much what all the Chi Fi amps manufacturers use in their designs now.

Hypex and Purifi chips are supposedly better in terms of specs - but my TPA Eval Board build sounded every bit as good as a Teac Hypex amp so I sold that and moved on.

All that said - I still listen primarily to class AB, or my class A amps... just "because", maybe it's nostalgia or maybe because the bass is just a little bit better and the amps are heavier lol. Seriously.
 
mrehorst said:
I have a Wiim Amp Pro and a Wiim Amp Ultra. Both sound great, and you can't beat the built in functionality. I use the Ultra with the Quads and SVS 3000 Micro sub. The sub gives me the lows the Quads can't produce and because the bass management in the amp is configured as a crossover. It keeps the lows out of the Quads allowing them to play everything else louder. And it's all controlled with my Android phone or tablet. Select some music, hit play, and the amp wakes up and starts playing. Within a couple seconds, the sub wakes up and starts playing. A few minutes after the music ends, they both go back to sleep. There are no knobs to twiddle, no switches to flip, no remotes to juggle or clutter up the living room.

Are they going to be usable in 10 years, 20 years? We'll see. If I get 5 years out of them, and they don't destroy my speakers, I won't mind replacing them. The bigger question is whether we will still be streaming music, using wifi or bluetooth in 5 years.
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Off topic, but what do you see replacing streaming? Everyone going back to physical media and/or downloads?
 
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