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Fosi v3 Mono - User Impressions | Owner's Thread
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Miser_Audioman
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Yes, after all not everyone is A-B testing these, many going to new systems etc.
My two V3 Mono’s are set to “Auto” and generally work great with my WiiM Pro Plus. However, one of them keeps clicking on and off when nothing is playing. What could be the problem? Have the single 48w/10A PS hooked up to them via the supplied noise filter.
DannyBoyNYC
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II have the same problem (with a WiiM Ultra). Also using a single power supply with noise filter. I guess the first test would be to disconnect the amp and WiiM to see if a signal is the culprit. Also... tried the phono input on the Ultra and the amps started a feedback cycle which could only be resolved by powering them down.
After having unplugged the WiiM Pro Plus from the rca-input of my V3’s it is apparent that the issue is related to the input signal. Without anything plugged in through rca both amps stay idle when in auto. Plugging the WiiM back in again introduces the problem again. Both of my V3’s now randomly flick on and off. Really annoying. Although the issue is only present when a streamer is plugged in it does seem to me that the fault is on the amps’ side. Anyone not having this happen with theirs?
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Mine did not do this in Auto mode when attached to my Schiit Freya+ preamp, even when the preamp was left on and not muted.
-Ed
That implies the WiiM is sending out random noise just strong enough to cross the threshold and trigger the V3 on. Those thresholds aren't assessing the quality of the signals (whether it would be music to our ears or not), just that some signal arrived. It's a worse problem if they don't turn the amps on when the signal is some fairly quiet start to a musical passage, so the thresholds are generally set to be quite sensitive to any signal at all. Could the WiiM be getting noise from its own power supply?
It could equally be problems with the PSU/Filter arrangement of the FOSI - if that is causing ground issues, that can also cause the amp to see noise on the inputs. This is where my suspicion lies due to the known issues of running the two amps of one PSU (Why they had to create the filter in the first place)
It seems (I was told by people in this forum that made such designs) that making an audio sense with the right sensitivity and immune to foreign events isn't easy. I am not surprised that Fosi design isn't perfect, but at the end, what matters (to me) is that the device doesn't stay on 24/7.
That said, if power consumption in this stand by mode is as high as some have reported here (3w/channel), the whole feature doesn't make sense to start with ....
That said, if power consumption in this stand by mode is as high as some have reported here (3w/channel), the whole feature doesn't make sense to start with ....
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Sokel
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These were the child diseases sense triggers had when they first used.
The right way is SingalSense+ and SignalSense- inputs should be low pass filtered to reduce the risk of false triggers from high frequency spikes (like A/C,led lights PSUs,etc) .
That,along with proper grounding makes them work properly.
We must always check what comes in of course,before the amp, but that's a given.
I tried capturing such a spike,there you go,that's HVAC:
(I had to connect PC to a non dedicated line but still,you can see it at about 18kHz)
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I have the same Pro+, 10A +filter and V3s setup, so far mine is working fine and I don't have any auto problems. My amps are arranged differently though - side by side with some space around them.
Am also currently waiting for my WiiM Ultra. Let us hope that ours come without this issue
If it is ground noise, it is a system issue rather than a component one. It will depend on all the kit in the system - all the wiring - how everything is grounded, and possibly including nearby but unrelated equipment.
I received mine today and got them hooked up straight away, set to auto. I ran them for about 30 mins but haven't since then (about 2 hours since). One of them is significantly hotter than the other one. I'm wondering whether the auto stand by has kicked in on one of them but not the other one? How can I tell if they are in stand by?
I've got a major concern if one of them is always going to be hotter than the other. I've swapped out my Aiyima A03 Max (I ran those in mono to) and they didn't get as hot as the hottest one is. The heat is particularly concerning given that I've not actually feeding either of them a signal.
Unlike @T&T, I've not rolled any op amps. I just plugged and played.
Makes me wonder if this could be an issue related to my turntable, which is not yet grounded as it is connected directly to the line in port of my WiiM Pro Plus. The WPP does not have a ground input or a phono input. I will ground the turntable, and most likely run it through the phono stage on my WiiM Ultra when that lands on my doorstep.
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