Just got one of those chinese chip amp: wow!

amplifiers, receivers and loudspeakers

Ever tried a class D chip amp?

Yes
10
43%
No
13
57%
 
Total votes: 23

HibouProfane
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Just got one of those chinese chip amp: wow!

Post by HibouProfane » 01 Jan 2010 18:51

I've been very curious about these class D chip amps for a while, so I finally ordered one from a Hong Kong eBay seller. It's a very small, very simple model, with only the power switch and volume control at the front and one pair of RCA inputs and one pair of speaker outputs at the back. It's about the size of a full size paperback novel. It's rated at 40 WPC at 4 ohms and 25 WPC at 8 ohms, 0.1% THD, which is impressive considering the size. I use it with my computer to drive a pair of old Mission bookshelf speakers.

All I can say is : WOW! Beautiful transparent cristal clear sound, with tight bass and smooth, well defined highs. For the price I paid, 99$ plus 28$ shipping, it's one of the best audio purchases I ever made. Serious! It's the perfect amp for crowded or small computer rooms. I'm even considering getting a pair of the 90 W model to bi-amp my Linn speakers in the living room.

Has anybody else tried a class D chip amp with similar satisfaction - or not?

Here's a link to the model I bought:

http://cgi.ebay.ca/ws/eBayISAPI.dll?Vie ... K:MEWNX:IT

And a happy New Year to everybody!

Guest

Post by Guest » 01 Jan 2010 21:42

Yessee, but not the little ones. For me the benefit comes from reserves of power for dynamic range at high SPLs, so around the 1kW+ range, which is generally a bit much domestically. If anything, they are toward the 'honest' and clean sounding IMO, and much depends on the PSU as always in these things. But no surprise if some of the little class D's punch above their weight, IMO. Happy New year Hibouprofane !

Finger Painter

Post by Finger Painter » 01 Jan 2010 23:14

Great to hear some praise here.

I was (and still am) contemplating getting one the next time home for here on the ship. This place seriously needs some sounds. Thinking of near enough the same, small speakers and a DVD player. Easy enough to carry in a bag.

Enjoy

HibouProfane
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Post by HibouProfane » 02 Jan 2010 00:16

It isn't Class D, it is a proper analogue Class AB amplifier for a brilliant price!

Regards

Dave
Sorry to argue with you on that, but those amps are definitely class D, which is analogue in spite of being sometime wrongfully called digital amplification. People get confused because they work on an on/off principle and are built into an integrated circuit, but at the end of the day, the signal stays in the analogue domain and is never treated as binary information.

The best proof it's class D is that it never gets hot, even after hours of use at good volume, because of its 90% efficiency. A class AB would get much hotter than that.

This said, I agree about the price. It is a great deal!

pivot
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Post by pivot » 02 Jan 2010 01:19

HibouProfane wrote:
It isn't Class D, it is a proper analogue Class AB amplifier for a brilliant price!

Regards

Dave
Sorry to argue with you on that, but those amps are definitely class D,
No need to argue - assuming the LM4766 chip is really used in the amp

Read the spec sheet here:
http://www.national.com/ds/LM/LM4766.pdf

The chip is not class D but class AB.

I have a couple amps around based on Tripath TA2024 chips. The Tripath class T is a variant of class D and the chips get rather warm at idle.

HibouProfane
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Post by HibouProfane » 02 Jan 2010 01:24

I'll be damned!

I thought all chip amps were necessarily class D. It still sounds good and still runs cool, though.

My apologies!

Alec124c41
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Post by Alec124c41 » 02 Jan 2010 02:55

I have one of the first Sonic Impact Tripath amps. An iPod, a pair of small speakers, and it sounds ridiculously good, and portable.

Cheers,
Alec

vincula2008
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Post by vincula2008 » 02 Jan 2010 08:33

A friend of mine has one amp from Trends Audio T-10 Class D amp driving a pair of homemade horns.

http://www.trendsaudio.com/index.php?op ... &Itemid=28

He was missing inputs, so he added the convenient Rotary Switch Box manufactured by Decware, so he can swap equipment and try valve power amps with a volume pot.

http://www.decware.com/newsite/rotary.htm

The results are surprisingly good. For that kind of money -and even for much more- I haven't heard a more life-like rig in my entire life :shock: . I'm seriously considering getting one as a back-up, in case I decide to tweak, upgrade or just need my valve amp serviced at some point.

They're a great deal of fun \:D/ !

Regards,

Vincula

mrw00ds
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Post by mrw00ds » 02 Jan 2010 09:04

It must be good - the volume goes up to 100! Spinal Tap eat your heart out!

LPspinner
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Post by LPspinner » 02 Jan 2010 11:37

Hi Guys.

Looking at the Data sheet the LM4766 from National semiconductor is definitely a standard class AB (Quasi Complementary) amplifier, and that’s not a bad thing. Personally I’m yet to be convinced that most Class D amplifiers have real merit as a high-end audio amplifier.

National semiconductor’s overture range of integrated power amplifier modules can yield some amazing results when handled appropriately. Despite some ill informed nay-saying there are several advantages to running a monolithic amplifier on one piece of silicon, the output pair within the monolithic device have to be very well matched for a start (as they share the same substrate). Also the DC voltage offset within the monolithic amplifier can be very well controlled and as the input pair is also very well matched the distortion generated within the amplifier can be very well controlled. The only real disadvantage of monolithic “chip-amps” is the dissipation of power (and therefore heat). A small piece of silicon will have trouble delivering high levels of current for a protracted period of time.

On the positive side I have used the National Semiconductor LM3886 (considered to be the best and most flexible of the overture range) as a power amplifier and have been pleasantly surprised on more than one occasion. Carful partnering with sensitive and non reactive loudspeakers should ensure that the amplifier is never driven into clipping, under these conditions the amplifier will perform floorlessly.


Enjoy the little HLLY M-1 40W HiFi AMPLIFIER and appreciate it for what it is. Looking at the images on the net it looks to be nicely specked inside and competently built as well … Good things can indeed come in small packages….

Happy listening

LPSPinner.

tubelicht
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Post by tubelicht » 02 Jan 2010 13:35

Looking at the picktures on Ebay and it looks good.
Big oversized transformer .. verry good.
2 big caps to smoothen the power ... very good
But it cant be class A-B because the heatsink is way to smal for that.
But i believe it can produce a great sound.
I have chinese amps, and a cd player that is build in china for a french company. They make great stuff for less money and still sound good.

CallMeJoe
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Post by CallMeJoe » 02 Jan 2010 16:48

LPspinner wrote: ...Careful partnering with sensitive and non reactive loudspeakers should ensure that the amplifier is never driven into clipping, under these conditions the amplifier will perform floorlessly...
How does the combination perform in a room with a floor?

LPspinner
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Post by LPspinner » 02 Jan 2010 19:47

Hi Guys:
Tubelicht wrote:…But it can’t be class A-B because the heatsink is way to small for that…
Page Six of the Data sheet clearly shows a Class AB Quasi Complementary Output stage. Under normal music conditions the heat sink shown will probably be enough to dissipate any heat produced. If the amplifier is expected to deliver its full 2 X30 watt output continuously you may run into thermal issues. Consider also that the heat sink is bolted to the chassis, which is also aluminum; the whole chassis / case becomes the heat-sink.
CallMeJoe wrote:
LPspinner wrote: ...Careful partnering with sensitive and non reactive loudspeakers should ensure that the amplifier is never driven into clipping, under these conditions the amplifier will perform floorlessly...
How does the combination perform in a room with a floor?

Oops, :oops: I usually run my posts through a spell checker before I post them up, however; as demonstrated, the one thing a spell checker won’t pick up is the incorrect usage of a correctly spelt word…

Substitute floor with flaw and the meaning of the sentence should be a little clearer.

LPSpinner.

tubelicht
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Post by tubelicht » 03 Jan 2010 11:25

There is an option to bridge them that's intresting.
Didnt know the heatsink was connected to the case.
I did build a 2 x 15 wat pure class A amp with verry large heatsink's
and still the temerature went up to 54 °C (129 °F) when not in use.

http://94.100.115.45/506650001-50670000 ... _6H8H.jpeg

This one is based on a Mullard design.
It costed me about 350 euro (505 usd) to build it myself.
So 99 dollar for this amp is peanuts.
and like i said before chinese amp's ain bad i got 2 yaqin's myself.

davidsrsb
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Post by davidsrsb » 03 Jan 2010 11:49

Linn once made an integrated amp with 6? National chips arranged 3+3 parallel and a switched mode power supply

This had a small heatsink
The chips are AB, but need paralleling to drive 4R loads well

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