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oldric_naubhoff's picture
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RE: I22 amplifier looks nice

bh69 wrote:

I22 amplifier looks very interesting (I hope it can be good solution for low level listening because of low distorsion and strength of class D). What seems curious to me is DAC modul. Why to convert D/A in case of digital amplifier ?? There is useless D/A & A/D cascade where sound can be modified to worse ...

there's no such thing as a digital amp in the sense you have on mind. class D amps are often called digital amps but this is just a misconception which IMO has it's roots in the fact that digital devices and class D amps exhibit bipolar scheme of operation - they are either on or off and nothing in between. however, class D does not amplify digital stream but normal analog waveform. no amp can do anything useful with a digital stream because it's just signals and quiets and sound we listen is comprised of various frequencies from range 20 - 20kHz (but you know it). so there has to be D/A conversion of digital signal before amplification can be done even in case of digital/ class D amps.

Anonymous
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RE: I22 amplifier looks nice

I'm not expert, but based on simple schema of class-D principe - http://www.maxim-ic.com/app-notes/index.mvp/id/3977 -  I think it should be relatively easy to use digital signal (nothing else as stream of amplitude values) for driving pulse generator. Those triangle signal and comparator with audio signal would be replaced by this digital control unit.

Maybe I'm wrong, but Lyngdorf amplifiers work similar way ? Some of them has no analog inputs at all.

 

oldric_naubhoff's picture
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RE: I22 amplifier looks nice

bh69 wrote:

I'm not expert, but based on simple schema of class-D principe - http://www.maxim-ic.com/app-notes/index.mvp/id/3977 -  I think it should be relatively easy to use digital signal (nothing else as stream of amplitude values) for driving pulse generator. Those triangle signal and comparator with audio signal would be replaced by this digital control unit.

but as you can see from the first schematic you still need to mate analog wave with triangle wave oscillator. you are also correct that all you need are amplitudes but this exactly the reason why a class D amp needs analog wave input. look at it this way. amplitudes values are buried within digital stream but unless they are converted to analog this information will not recovered. PWM will see digital stream for what it is, which is just a square wave of impulses and lack of impulses. so what you'd get from your speakers would most likely resemble listening to Morse code but with much faster.

bh69 wrote:

Maybe I'm wrong, but Lyngdorf amplifiers work similar way ? Some of them has no analog inputs at all.

same thing with Devialet. it's a purely digital device and although you'll find analog inputs there the signal gets transformed to digital on entry in A/D converter, so it's better not to use analog ins due to inherent A/D D/A conversion. anyway, the power amp section is analog. it has to be or class D amp wouldn't know what to amplify. and I'm pretty sure those Lyngdorfs, even without analog inputs work in the same fashion.

despite the fact that many people call class D a Digital amp it's truly just another type of analog amp output stage. so, you could make a "Digital" amp (by saying that I mean having only digital inputs) and equip it with a class A output stage and its working principle would not differ much from the same amp equipped in class D output stage. the only difference would be that it'll be bulkier, will run hotter but will sound much better Smile

Anonymous
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RE: I22 amplifier looks nice

But only thing what this D-amp needs is to know how long should be output sestion "open" and how long "closed", depending on actual signal value. The fact that signal is digital makes no morse code, but a stream of numbers - in case of CD quality 16 bit values in 1/44100 second intervals. With a small  processing it that can be used for driving switched output.  All still digital - little control unit would switch on/off. I think it's more logical and pure way. Of course most people want analog inputs still and then a A/D converter would be needed.

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RE: I22 amplifier looks nice

bh69 wrote:

But only thing what this D-amp needs is to know how long should be output sestion "open" and how long "closed", depending on actual signal value. The fact that signal is digital makes no morse code, but a stream of numbers - in case of CD quality 16 bit values in 1/44100 second intervals. With a small  processing it that can be used for driving switched output.  All still digital - little control unit would switch on/off. I think it's more logical and pure way. Of course most people want analog inputs still and then a A/D converter would be needed.

the way I see it you're describing how a normal DAC works but instead getting output signal in fractions of volts you want to get signal capable of driving speakers. interesting. but is it possible? and more importantly worthwhile?

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RE: Primare I32 a Digital Amp?????????

Leaving aside your side-swipe at WHF, the reviewers may have got it wrong (about the sound) on this occasion - afterall, they are only human! Having heard this product compared to a MS M6 & Supernait in Oxford - I was amazed by the sound quality. Its level of detail was quite stunning but also sounded unforced with excellent dynamics & timing. I cannot coment on whether or not they reviewed a representative sample or not.

WHF certainly got the review of Audiolab's M-DAC absolutely bang-on in my opinion though - punches well above its weight! Equally stunning sound to the Primare.

 

Mac Mini - USB - M-DAC+ - XLR -  Primare Pre32 - XLR - A34.2 - Quadral Chromium Style  8. CA azur 751BD. oak Podium rack, B&W P5 Wireless, iPhone 6s 

Anonymous
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RE: I22 amplifier looks nice

> the way I see it you're describing how a normal DAC works but instead getting
> output signal in fractions of volts you want to get signal capable of driving speakers

yes, it's similar but there is a one important diferrence - DACs don't use switching (pulse modulation) that enables big power on output

 

 

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RE: I22 amplifier looks nice

I am in the market for a new integrated amp and the Primare i32 is on my list as so the Exposure 3010s2 and the Roksan Caspian m2.

Could anyone tell me if there is a big difference between the i30 and the i32? Because WHF really liked the i30 and the i32 not so. 

 

 

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RE: Primare I32 a Digital Amp?????????

I've been listening to the Primare I32 for the last week. Stunning amounts of clear detail as previously stated. Where personal responses will enter the equation is that it's clearly got a different texture to the toroid-based amps many of us are used to. I found it a little mechanical compared to some recent British amps but am prepared to accept that this is more a matter of taste than inherent quality (though I tend to agree about the treble).

Or to state the obvious - we're all so used to the Arcams, Naims, Regas and Roksans of this world that this kind of amp may seem too radical. In terms of telling you what's on your CDs, though, I can't imagine much better - in fact it says a lot about what is coming off your CDs, LPs etc, and points a critical finger at some pretty expensive amplification in terms of losing information. Listen first.

:clap:

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