New to this -- recommend a good ~50Wpc board?

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I'm looking for a way to make an inexpensive stereo amp out of kit boards. 50 watts per channel should suffice. The intended use is as a gift to someone who plays classical music and opera CDs and FM radio into a pair of floorstanding speakers of moderate efficiency.

I'm a tube hobbyist person, so am not adept enough at solid state to build from scratch. Figured I'd get my feet wet with a kit. I'd buy the enclosures separately, along with the jacks, binding posts, etc.

I was thinking I'd put an input selector switch and volume control in there and call it an 'integrated' amp. There's no need for a tape monitor loop.

What is the typical input sensitivity of these amp kits? Would the output from an FM tuner be capable of driving one to near full power? (I figure about 250 to 500mV from the tuner, but I don't know for sure.)

How do these Class D amps sound? Are they comparable to store-bought receivers in the $500 USD range? Or (hopefully) a noticeable step up from that?

So, what are the best kits available these days? Chinese stuff from Ebay? If so, are there really good ones to get? Others in particular to avoid? Or does Parts Express have a good kit that will fill the bill?

I'm basically looking for a pleasant (non-aggravating) sounding amp for cheap.

Thanks.
 
Class D amps are designed for efficiency, not sonics. An analog solution would probably be more fitting. Many people in fact try to avoid chips... But that is the purist approach.

I usually see a 50k input pot being used in amps. Usually there is a high-value resistor right at the input, to precharge the input cap which prevents loud pops when switching. Apart from this I've never heard complaints about volume controls. However for purists there are "constant impedance" stepped volume controls...

- keantoken
 
Okay, I'll rewrite that a bit. Yes they are designed to sound good, they must to sell. But from what I hear, they still don't compete with the analog alternatives. So if you don't need the efficiency, why would you even consider one? This was my line of logic.

Opinions are scary, yes they are,
- keantoken
 
Hello

I agree with keantoken, a very well designed analog amp will have more musicality, a better sound stage and a more engaging sound compared to a class D. For sure you need to use an excellent cd player and well recorded music cd to ear the differences.

Class D are still a young design compared to analog amp, so we will see how they will develop in the future.

Bye

Gaetan
 
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good morning Sir ! My greetings to the midle-ages ....:D

Hello

Do some serious blind tests listenings of some the best high-end analogs amps compared to the best class D amps, you will ear the differences, class D sound much less musical compared to the best high-end analogs amps.

No need to tell more, since the thread are not about that.

Bye

Gaetan
 
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the best high-end analogs amps compared to the best class D amps

That's likely true for the best amps, but it might be more interesting to compare amps DIYers can build for $2-300 in parts; that is where I think the new crop of Class D amps really shine. They seem quite good for very little investment.

And rongon, Parts Express is now selling Sure amps and power supplies that might suit what you're after.

Sure Electronics - DIY Projects, Amplifier Kits, Class D Audio Amplifier Boards, Power Supplies - Offered at Parts-express.com
 
Hello

class D sound much less musical compared to the best high-end analogs amps.

Bye

Gaetan

Hi Gaetan,

1) perhaps a little bit confusing this class(ical)-D. And it´s input signal is also analog like class A/B. Of course there are some models out there which want digital signals for breakfast.

2) I should also speak better about chip amps to avoid missunderstoods which are not pure class-D. I read a topic regarding this where a concerned class-D purist wanted the chip amps removed a Tripath to the chip amp section.

Under this light you might be right but I definetly recommend a Tripath to check it up ;)
 
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Hello

I should say that I listen to very high-end amp since I was in Montreal in the 80's, a friend of mine did have a high-end audio store. Now I go every years to the Montreal audio show.

I have a Radford HD-250, few transistors amps and few tube amps and Dynaudio speakers.

But having also try those chip amps, the TDA7293 and the LM3886, I can say that the LM3886 are not bad for a chip amp and better than the TDA7293, they are not class D amps but standard class AB amps in a big chip.

Rongon

Those LM3886 cost low price and it's easy to buid an amp with that chip, and there is lot of pcb and kit on the Net, look at:

DIY Chip Amplifier Kits, PCB's, Components and Information.

Bye

Gaetan
 
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UUhhh ... dynaudios ? If these are further bookshelfs I can imagine that your tubes often sweat. As I know this brand's speakers usually demand more powerful amps with higher damping factors. So chipamps are'nt the big solution for you. Especially these gaincards.

Wishes

Hello

Yes, Dynaudio are not very efficient speakers but they sound superb, those Dynaudio use the 17W75 woofer and the box have 2 feet tall.

I listen jazz most of the time and I rarely listen it loud even with more efficient speakers.

Chip-amps have less precision and have a flater soundstage compared to my Radford and my others amps, so my chip amps are gone since long times.

Bye

Gaetan
 
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