Need some help/advice on my Fosi ZA3 setup (issue with running in mono)

[Mutagen]

Hi all -
I've got a pair of ZA3 amps from Fosi that I picked up from their kickstarter campaign. Both amps function properly in stereo mode. I'm seeing a strange issue when I use them in mono mode, however. Here is the description:

When I connect either amp to a source (I've tried both RCA and XLR), it works properly (signal comes in from my DAC or from a WiiM mini, and music comes out of my speaker). Again, both amps function properly this way.

However, when I connect both amps to the source (using them as monoblocks), only one of the amps produces sound. The only way to get sound from the second amp (discovered after much trial and error) is to unplug the input cable (again, either RCA or XLR will do this) and then reconnect it WHILE signal is being sent (so, a hot plug). Both amps then run properly until I power the system down. After than, I need to repeat the hot plugging process to get sounds from both speakers.

I've contacted Fosi - but I'm asking here in case anyone has thoughts about what might be happening. Is it possible I've configured something improperly? It's not that complex of a setup, but hey, worth investigating!

Many thanks!

 

[charlielaub]

Have you tried swapping "sides" with cables and amps to pin down whether the behavior is one amp or the other, or one channel (from upstream) or the other?

 

[Mutagen]

Hi - yes, and thanks! I can get both of the amps to do this (that is, produce no signal when connected in various orders, then come back when 'hot' plugged to the line in, on both RCA and XLR). It's perplexing - something wrong with the triggering process?

That said - I've just left everything on and it sounds great! Not ideal . . .

Cheers.

 

[Glades]

Hi - yes, and thanks! I can get both of the amps to do this (that is, produce no signal when connected in various orders, then come back when 'hot' plugged to the line in, on both RCA and XLR). It's perplexing - something wrong with the triggering process?

That said - I've just left everything on and it sounds great! Not ideal . . .

Cheers.

Seems not right. Same setup and in mono: source L-channel out in 1st ZA3 (red RCA) line in, R-channel out in 2nd ZA3 (also red RCA) line in, although I suspect you did that. Out of habit I plugged one source channel in the white RCA in, so sound from one speaker at first

 

[patrick1112]

Hi all -
I've got a pair of ZA3 amps from Fosi that I picked up from their kickstarter campaign. Both amps function properly in stereo mode. I'm seeing a strange issue when I use them in mono mode, however. Here is the description:

When I connect either amp to a source (I've tried both RCA and XLR), it works properly (signal comes in from my DAC or from a WiiM mini, and music comes out of my speaker). Again, both amps function properly this way.

However, when I connect both amps to the source (using them as monoblocks), only one of the amps produces sound. The only way to get sound from the second amp (discovered after much trial and error) is to unplug the input cable (again, either RCA or XLR will do this) and then reconnect it WHILE signal is being sent (so, a hot plug). Both amps then run properly until I power the system down. After than, I need to repeat the hot plugging process to get sounds from both speakers.

I've contacted Fosi - but I'm asking here in case anyone has thoughts about what might be happening. Is it possible I've configured something improperly? It's not that complex of a setup, but hey, worth investigating!

Many thanks!

HEllo, I have 2 ZA3 mono. It happens to me also when installing the RCA cables, just need to move the switch to stereo, and back to mono. Pb fixed. It happened only during installation, like if needed a signal reboot. Not an issue for me.