The New Hypex Fusion Plate amps

I have a question I couldn't find an answer skimming the topic, maybe I missed it, if so, I am sorry

I have connected my speakers to fa253 (3way) and I installed the oled and remote. I use analog xlr inputs on both amps. I use spdif/coax for controlling the slave unit pogram change messages.

The question is, with this setup I can omit the preamp and connect my source directly to fa253 and with this setup I have to listen around from about -30 to -20. Do I loose bits this way. If I use a preamp I set them at 0 and used my preamp for attenuation.
The only way to never lose bits is to listen at full volume at all times. But don't worry, the FusionAmps will not rewrite the music in Spotify with less bits.
 
Depends on how you define "lose bits". Any time you do any attenuation/scaling you change the data (be it in digital or analog domain), but if the digital operation is done with sufficient intermediate precision, you don't lose "resolution". What you will lose is signal-to-noise ratio, simply because an attenuated signal is closer to the noise floor - but any way you attenuate, it is the same issue.
 
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I have connected my speakers to fa253 (3way) and I installed the oled and remote. I use analog xlr inputs on both amps. I use spdif/coax for controlling the slave unit pogram change messages.

The question is, with this setup I can omit the preamp and connect my source directly to fa253 and with this setup I have to listen around from about -30 to -20. Do I loose bits this way. If I use a preamp I set them at 0 and used my preamp for attenuation.
That's actualy the optimal setup with analog connection! You use the full resolution/ S/N ratio of the input A/D converter with your source fully on and then tame the volume digitally (and also reduce noise and artefacts of the source at the same amount).

So when this is comfortable enough for you stick with it!
 
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Does anyone else using transformer coupled ribbon tweeter with the Fusionamp?
One of my FA253 puts out high pitched whine through the tweeter when this type of tweeter is connected to it. No matter if connected directly or with a series capacitor or with a 2nd order passive filter. Tried a dome tweeter, no whine at all.
What could this be?
 
Just a thought: could it be caused by a SMPS coupling to the tweeter's transformer? According to this link it has an on-board SMPS module (mention of the SMPS is in the page title):

https://www.hypex.nl/products/amplifier-families/fusion-amplifier-family/fusionamp-fa253

From this EEVblog thread:

"There is no such thing as a "silent" SMPS. I have used a boost converter to create the HV for a couple of tube-based guitar products and the noise generated by the switching can be pernicious and infectious. The noise finds its way into other circuits by conduction through the SMPS output and radiation from any/all inductors and conductors that handle the high voltage.

Any suggestions/arguments that the noise is easily filtered out because the frequencies involved are above human hearing are fallacious. Even if the supply is working at a nominal 100KHz, its regulation will use frequencies that extend all the way down through the audible range, all the way to a few tens of Hz. The feedback paths in the regulator will be modulated with a significant amount of random or not-so-random noise so as to also modulate, not only the output voltage but also the timing of high voltage/current switched signals with audible noise frequencies. These high voltage signals will be broadcast through the air to every conductor within the unit, thus carrying the audible modulation there as well. High frequency noise as well as the audio-frequency modulation noise conducted via the SMPS output will not only be directly injected into any circuit that it supplies but also take advantage of that power network as an antenna system to further infect everything else in range."
 
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Still have same problem. Somehow it was working good for 1-2 days when adjusted as I say before but now no way to properly start it.
Even if I start first slave mode and volume is locked when started the amp going mute. When change preset by remote went out of mute but stay on -96level.
If anybody know please some advice.
Working on a new build tonight and turns out that I had the same issue. The problem arises when you turn on the master unit before the slave.
 
"There is no such thing as a "silent" SMPS.
There is no such thing as a silent conventional power supply! I had plenty of power amps on my table but NEVER had one with no remains of the 100Hz diode switching frequency - and it get's worse when power is needed.
SMPS has the chance to be so much better - and often is. But of course there are bad & cheap examples with every form of power supply.
 
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@YSDR I'm guessing here, but it's likely that a component (especially eg a capacitor) that went out of spec. From what I read in the above link, it seems like it's way more difficult to de-noise a SMPS design (as opposed to throwing in a set of FREDs in a linear supply). So if something goes partially south, that could be putting the supply out of design tolerances, creating more noise, and coupling into the tweeter transformer in just that one amp.

Would be interesting to know what SMPS that Hypex uses, and if there's a known reliability issue with some of them. Hypex is great stuff overall. I'm interested in being able to debug them over time (which includes things like swapping out the SMPS in the field due to failure).
 
The SMPS in a FA is integrated to the power amps, its called NC-MP wich means "mains powered Ncore", so a single PCB solution, except for the 3 way plates (which I have), where there is an additional amp with its own PCB for the high frequency section, but this are powered by the same common power supply as the other channels.
As far as I know these are built with very cheap chinese junk capacitors, I wouldn't be surprised if one or more of them broke after this time.
 
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