The New Hypex Fusion Plate amps

[Cableaddict]

Interesting. I thought all class D amps had a digital first stage.

I do agree that good ADA these days is basically transparent (well, mostly) so this is more of a theoretical discussion.

To some extent, I'd be more worried about SR conversion, which is definitely observable when not done properly.

 

[DcibeL]

Class D amplification is not digital. All amplifiers are analogue, some are just more analogue than others, explained in a Hypex white paper that you can read here:
https://www.hypex.nl/img/upload/doc/an_wp/WP_All_amps_are_analogue.pdf

 

[Cableaddict]

Class D amps literally used to be called "digital" amps. AFAIK, (though I'm not an amp expert) they always had a digital front end (controller) At least until recently.

I didn't realize that there are now analog-controlled D amps. (And theoreticaly they sound better.)

There's some interesting info here, though I admit I don't understand all of it.
A relevant paragraph:

"Digital Class D amplifiers directly convert PCM digital signals into amplified analog output to drive a speaker; what is sometimes referred to as a ‘power DAC’. In contrast, an Analog Class D amplifier uses digital techniques to amplify a small analog input voltage into the power required to drive a loudspeaker. "
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What confuses me is, why would an amp with AES input not just use a digital controller? I'm sure I'm completely not understanding the technology, but I'd love to understand this at a basic level.

 

[DcibeL]

Start with the paper I directed you to, plenty of good information in there. Information on your "power DAC" scenario starts on page 3.

 

[U101222]

I think what jccart is asking is: (apologies if I'm wrong)
Does the AES input bypass the digital converter, or does the analog input bypass the converter?

I'd like to know as well.

Being a class D amp, I would assume that the AES input goes directly to the amp's circuit, whereas the analog input has to be A-D converted first.
- And thus the AES connection has the potential to sound slightly better. (Especially if your processor has an AES output.)

But I'm guessing. Does anyone know?

The documentation states indeed that if you use analog inputs the signal has to be digitised before it goes to the DSP.

 

[DcibeL]

Of course, for anything "DSP" like the Fusion plates, unlike "class D" the D in DSP absolutely is for "digital", the processing is done in the digital domain, so any analog input will have A to D -> DSP -> D to A -> amplification.

 

[jccart]

OK thanks what I wanted to do was use the fusion amp for a sub then use the analogue output to an active monitor without going through an adc stage . OK ill have to think of another way of doing it . thanks everybody

 

[YSDR]

"OK thanks what I wanted to do was use the fusion amp for a sub then use the analogue output to an active monitor without going through an adc stage."

That's exactly how the Fusionamp works. The analogue line level (XLR) output from the Fusionamp is exactly the same analogue signal that is coming from the analogue preamp or other analogue source, it's not a digitized signal, it's not going through the ADC stage. In your case, the only signal that will be going through the ADC is the signal of the sub.

 

[jccart]

OK brilliant thankyou

 

[YSDR]

Cheers!

 

[U101222]

[...] objectively speaking, the digital inputs are better, because they have 2dB lower noise floor (-109dB vs -111dB) and 2.5dB lower THD+N (-100dB vs -102.5dB) than the analogue inputs, but it's very doubtful anyone can hear that difference with realworld sounds.

For instance, I am using the FA501 just for the 17-60 hz range (with "audible" output up to 120hz or so) so I highly doubt this difference in noise and distortion is audible at all. In fact, m the FA501 is overkill, but I like overkill.

 

[ds23man]

The one channel version don't have a digital input.

 

[jccart]

I was hoping that the crossover would be set using the laptop and then applied to the amplifier which then would somehow work using analogue on the xlr pass through. to provide a filtered signal without using an arc or dac . I know that was a bit wishful thinking. can anybody recommend a good analogue only playe amp with xlr crossover outputs please .

 

[jccart]

hang on if I did it the other way and used a hypex plate amp for the subwoofer could I go in digital and then the digital output could have a crossover filter applied by the the plate amp then just into a dac then into my powered monitors this seems like quite a simple way of doing it x

 

[YSDR]

No.
The digital out is just a through like the analogue out, "what comes in, that goes out". The external outputs (digi out, line level analogue out) on the Fusionamp doesn't go through the DSP.

 

[jccart]

OK thanks so its just a pass through . what does everybody use for an electronic crossover then mini dsp I suppose ? trying to find the best price performance option

 

[Kjeldsen]

I use the t.racks DSP 4x4 Mini

MiniDSP plateamps might have DSP on the outputs but Im not sure

 

[jccart]

ah ok I wanted to do all my crossovers in the digital domain and then convert to analogue using my choice of dac not the one in the device. it looks like nanodigi 2x8 might be a good option for me ?

 

[Kjeldsen]

Ok. Then you are left with quite few choises. I dont know of any but the MiniDSP range

 

[YSDR]

ah ok I wanted to do all my crossovers in the digital domain and then convert to analogue using my choice of dac not the one in the device. it looks like nanodigi 2x8 might be a good option for me ?

Yes, it can work, but then you have to control the global volume by the nanodigi. Otherwise you need to have a digital source with volume controlled digital output.
The miniDSP SHD Studio is much better (but more expensive) for that purpose, it's a full digital preamp with multiple output and remote control, plus many more function.