Hello, I need a small sized amplifier to drive a pair of minimus-7.
I guess the smallest size is a chip amp so I found this one Compact High-Performance 12V 20W Stereo Amplifier Circuit Diagram
Could it be considered as hi-fi (well classab..)?
Or can you propose another HI-FI amplifier to build (15-25W or so)?
I guess the smallest size is a chip amp so I found this one Compact High-Performance 12V 20W Stereo Amplifier Circuit Diagram
Could it be considered as hi-fi (well classab..)?
Or can you propose another HI-FI amplifier to build (15-25W or so)?
This depends heavily on what you consider to be 'hifi' but most (if not all?) of the low power class D offerings are single supply and run bridged to eliminate the need for DC blocking coupling caps.
There are a number of different modules and kits that you can buy from ebay and other various websites. Of all the chips on offer the tripath ones generally have the best specifications as per the datasheets - it is worth popping the chip part numbers into google and checking the datasheet performance because not all chips are identical.
The ones you want to go for show a flat or close to flat curve of THD (total harmonic distortion) vs frequency. Some Tripath models do this and so do the better offerings from Texas Instruments.
It is worth mentioning however that the datasheet performance isn't the same thing as any modules actual performance. The quality of the design and surrounding components are quite critical, especially in class D designs. You are however more likely to get a competently built product if the amplifiers rated output power is lower rather then higher as they are typically much less demanding.
There are a number of different modules and kits that you can buy from ebay and other various websites. Of all the chips on offer the tripath ones generally have the best specifications as per the datasheets - it is worth popping the chip part numbers into google and checking the datasheet performance because not all chips are identical.
The ones you want to go for show a flat or close to flat curve of THD (total harmonic distortion) vs frequency. Some Tripath models do this and so do the better offerings from Texas Instruments.
It is worth mentioning however that the datasheet performance isn't the same thing as any modules actual performance. The quality of the design and surrounding components are quite critical, especially in class D designs. You are however more likely to get a competently built product if the amplifiers rated output power is lower rather then higher as they are typically much less demanding.
Not always, it depends entirely on your personal preference, some people absolutely love the sound of the class-T stuff and praise them incredibly highly. The class T amplifier modules aren't really that expensive either, you could buy one and give it a go. For a power supply you could use any power adaptor within the voltage range, such as most laptop power supplies etc, or a battery.
Standard class AB style power amplifiers work best when powered by dual rail supplies, that is +- with a centre ground reference. If you could go that route then the popular gainclone would probably be safe bet as a simple chip amplifier.
Edit - here's a link to the chip used in the gainclones http://www.national.com/ds/LM/LM3875.pdf
On the matching amplifier for Minimus-7, the Realistic STA-19, you will find a pair of NEC uPC1238 amplifier chips. The closest match is TDA2006; however, TDA2030, TDA2040 are similar, except more powerful (less clipping).
See also this page for some kits:
http://www.parts-express.com/wizard...bPage_ID=3&searchFilter=amplifier+kit&x=0&y=0 <---link
See also this page for some kits:
http://www.parts-express.com/wizard...bPage_ID=3&searchFilter=amplifier+kit&x=0&y=0 <---link
The tda7377 in the link is probably better than tda2005 or 2006. IMO the amp looks pretty good for what it is. LM3875 requires 20 Volt minimum supply voltage. One drawback (to me) of bridge circuits is that they are unsuitable for headphone use. Original post said single supply, so the question is if OP has a supply (12 volts?) or would be building or buying that also. My own choice would be to use a split supply and one of the PCB's from chipamps.com .
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