Fosi V3 Mono block backer email - noise filter or two power supplies?

[Giro413]

Hi All, I realize that this is not exactly 100% Wiim related, however as many of us will be using the Fosi V3 Mono blocks with our Ultras I think this post will be ok.

I just received the following email from Fosi, and am in doubt as to what to do. Do I stick with the single 48V/10A power supply and this filter or get two separate 48V/5A power supplies?

Dear Fosi Audio Backers,

We've got some great news regarding the noise issue some of you mentioned earlier. We now have a solution, we've developed a power filter.
*This power filter effectively addresses any potential noise concerns that may arise when using multiple devices simultaneously, ensuring pristine audio quality*

Power filter

All backers who have chosen the 48V10A power supply + 2 sets of V3 Mono Combo will receive our custom-designed power filter for free!


If you still want to switch your 48V/10A power supply to 48V/5A, you can easily do so by changing your pledge.
You can contact our crowdfunding helper Jocelyn at marketing@fosiaudio.com for help.
Ps: We recommend modifying your pledge, as manual adjustments can lead to errors.

https://www.kickstarter.com/projects/fosiaudio/fosi-audio-v3-mono-power-amplifier/posts/4112662?ref=ksr_email_mktg_auto_backer_project_update_registered_users

 

[Brantome]

Hi, I’d say it’s nothing to do with WiiM at all, and it’s a big assumption that “many” WiiM Ultra users will use these amps, but I’ll let the post stand. In future, you perhaps would be better asking such a question in the Fosi forum if such exists, or in a device agnostic forum like ASR. Cheers.

PS my personal view is that you should stick with the 10A supply and accept the filter as I seem to recall from something I’ve read or a YouTube review I watched that the 10A power supply was a better solution than two 5A for some reason or other.

 

[harkpabst]

You need to actively change your selected option from
2 V3 Mono + 1 10 A PSP
to
2 V3 Mono + 2 5 A PSP
if you don't want to receive the filter and one PSP.

 

[Giro413]

Hi, I’d say it’s nothing to do with WiiM at all, and it’s a big assumption that “many” WiiM Ultra users will use these amps, but I’ll let the post stand. In future, you perhaps would be better asking such a question in the Fosi forum if such exists, or in a device agnostic forum like ASR. Cheers.

PS my personal view is that you should stick with the 10A supply and accept the filter as I seem to recall from something I’ve read or a YouTube review I watched that the 10A power supply was a better solution than two 5A for some reason or other.

You are of course totally right. But if I didn't post here I wouldn't get your two cents, which by the way is much appreciated I would much rather stick with one power supply than two, unless there is a really good reason not to. Thanks.

 

[amix]

Do I get stick with the single 48V/10A power supply and this filter or get two separate 48V/5A power supplies?

Why would you buy mono blocks but only a single power supply?

The reason for mono blocks is to have two separate, fully powered and equipped channels, that are completely independent from each other and work to the highest possible spec.

Monos are a luxury for those, who want the best technical solution, ready to pay the price for doubling the components.

I think you would be better off with a stereo power amp. This way you also can ensure, that you do not suffer from desynchronization in the amplifier chips. Monos are the (theoretical) best, as "ideal" solution when using Class-A or Class-AB amplifiers, but not for Class-D.
One might argue, that a single power supply, in this case, would be better, since the chipamp gets synced, as far as I know, from the power supply frequency, and with a single supply both chips get synced by one signal, but than there is no reason for monos (except the higher possible power output).

P.S. It would also be interesting how this filter achieves the filtering. I bet ten horses, it will alter, maybe dampen the sound. Might come with loss of transients.

I'd go for the 2x 5A supplies in your case (personally I went for 2x 10A but that's because my speakers want amps more than power).

 

[Giro413]

Why would you buy mono blocks but only a single power supply?

The reason for mono blocks is to have two separate, fully powered and equipped channels, that are completely independent from each other and work to the highest possible spec.

Monos are a luxury for those, who want the best technical solution, ready to pay the price for doubling the components.

I think you would be better off with a stereo power amp. This way you also can ensure, that you do not suffer from desynchronization in the amplifier chips. Monos are the (theoretical) best, as "ideal" solution when using Class-A or Class-AB amplifiers, but not for Class-D.
One might argue, that a single power supply, in this case, would be better, since the chipamp gets synced, as far as I know, from the power supply frequency, and with a single supply both chips get synced by one signal, but than there is no reason for monos (except the higher possible power output).

P.S. It would also be interesting how this filter achieves the filtering. I bet ten horses, it will alter, maybe dampen the sound. Might come with loss of transients.

I'd go for the 2x 5A supplies in your case (personally I went for 2x 10A but that's because my speakers want amps more than power).

Getting two seperate 5A's is definitely something to consider, if that comes with benefits. I will be hiding away the power supplies in any case, so the added cluster of having more boxes is more of a theoretical issue, really. So plus one for getting two separates from you. Thanks.

 

[amix]

Getting two seperate 5A's is definitely something to consider, if that comes with benefits.

Don't forget what I mentioned above! Fosi has this to say on their Kickstarter campaign FAQ:

How are you synchronizing the TPA3255 oscillator between the monoblocks in order to avoid Class D "Beat Tones" ?

Regarding the synchronization of the switching frequency, since multiple V3 Monos may be powered on at different times, and given that they operate on DC current along with a frequency of 450KHz, it is impossible to achieve perfect zero-phase synchronization directly upon powering up. However, in AUTO mode, it is possible to synchronize the startup of two V3 Monos when a signal is detected, to align the frequencies of multiple TPA3255 chips as closely as possible. Nevertheless, there will always be a slight margin of error.

So if you don't need the higher power you get via the monos, I'd go for the Stereo V3 or the ZA3.

 

[harkpabst]

So if you don't need the higher power you get via the monos, I'd go for the Stereo V3 or the ZA3.

It's not just higher power, though. Many seem to be after PFFB in the first place.

 

[amix]

It's not just higher power, though. Many seem to be after PFFB in the first place.

Ah yes, sorry, I totally forgot about that!