MC331: Low Volume Issues?

[Oswaldoiii]

Hey, thoroughly enjoying listening to music on this little amp except at lower volumes. The music or TV via BT or optical at lower volumes fades in and out or missing frequencies?. I have paired with my vintage Wharfedale Linton XP2’s and my smaller and modern Monitor Audio 50’s but the same problem. I’ve tested both on my older Sabaj BT4 and no issues.
I’ve read lots of good reviews about this amplifier so can it be a faulty one or am I doing something wrong?
Advice welcome..

 

[antalistvan1968]

Hi! try asking the question in the facebook group. https://www.facebook.com/groups/fosiaudiocommunity Be sure to write to fosi support as well.

 

[Oswaldoiii]

Thanks, to be fair Fosi have been great at their customer service.. awaiting their upgraded version with anticipation

 

[reunion8308]

I also ran into the exact same issue. I sure hope their service is good since this was gifted to me last year and I just found out about this while unpacking it . I haven't tried with another input (RCA), but even if RCA was to work, I need the Bluetooth and optical to also work fine since they're the inputs I'll use the most.

I also found out that it doesn't only happen at low volumes. It also happens when sound suddenly stop in a song. It kind of cuts the sound short. Tried it with bird sounds, since they usually produce very sharp noise to really make sure it was the issue. Sure enough, I don't even hear the full chirps, it just sounds like the bird was slapped halfway into his chirp.

I'll try to update the thread with the support they'll give me !

 

[Euli1988]

I‘ve the same issue with my MC331!

 

[reunion8308]

This is the official reply I received from them:

"Regarding your feedback on this issue,

The MC331 chip integrates analog Bluetooth, optical, and coaxial functions, the function is relatively powerful. Music types such as instrumental, classical, and piano sounds have a wider frequency range. This may result in a less prominent bass response under certain conditions.

To address this, increasing the overall volume by 20% to 30% can significantly improve the listening experience.

Meanwhile, our electronic engineers are actively optimizing the MC331's software to enhance its performance at lower volumes. We hope to resolve the issue of the MC331's underperformance at lower volumes as soon as possible. Once we have a better solution ready for testing, we will send it to you immediately."

For my part, I've tried increasing the volume, but I still faintly hear the issue, though less than when using low volumes. However, I live in an appartment, so this hot fix isn't very neighbour friendly.

 

[antalistvan1968]

This is the official reply I received from them:

"Regarding your feedback on this issue,

The MC331 chip integrates analog Bluetooth, optical, and coaxial functions, the function is relatively powerful. Music types such as instrumental, classical, and piano sounds have a wider frequency range. This may result in a less prominent bass response under certain conditions.

To address this, increasing the overall volume by 20% to 30% can significantly improve the listening experience.

Meanwhile, our electronic engineers are actively optimizing the MC331's software to enhance its performance at lower volumes. We hope to resolve the issue of the MC331's underperformance at lower volumes as soon as possible. Once we have a better solution ready for testing, we will send it to you immediately."

For my part, I've tried increasing the volume, but I still faintly hear the issue, though less than when using low volumes. However, I live in an appartment, so this hot fix isn't very neighbour friendly.

I got the same answer

 

[standlee]

I purchased the MC331 in early January,
and I’m experiencing the same issue where the music cuts out or the sound becomes unclear at low volume.

The issue occurs regardless of whether the source is USB, Bluetooth, or RCA, and whether the output is through speakers or headphones.

Just in case, I removed the 5654 tube, and the problem disappeared, so I assumed the tube might be the issue.
I ordered a new set of 5654 tubes and replaced it, but the problem persists.

For your reference, when I remove the 5654 tube, the output of the amplifier is significantly reduced, making it a bit insufficient to drive the speakers properly. It seems that the tube is involved in amplifying the sound.

I would appreciate any possible solution to this.

 

[antalistvan1968]

I purchased the MC331 in early January,
and I’m experiencing the same issue where the music cuts out or the sound becomes unclear at low volume.

The issue occurs regardless of whether the source is USB, Bluetooth, or RCA, and whether the output is through speakers or headphones.

Just in case, I removed the 5654 tube, and the problem disappeared, so I assumed the tube might be the issue.
I ordered a new set of 5654 tubes and replaced it, but the problem persists.

For your reference, when I remove the 5654 tube, the output of the amplifier is significantly reduced, making it a bit insufficient to drive the speakers properly. It seems that the tube is involved in amplifying the sound.

I would appreciate any possible solution to this.

please be sure to write to the customer service on the official website of fosi audio. it is important that they know about it. . they will surely find a solution for you