New Fosi V3 Stereo - volume sometimes stuck on 50% and just one channel

[korgua]

Hi,

I just swapped out an amp for a new Fosi V3 Stereo and have a problem where the amp will sometimes drop to one channel and not respond to any volume control on the front dial.

The setup is an SMSL SU1 connected by RCA.

The system was working fine with all the previous components and cables, I just swapped out the amp for a V3.

It will work on both channels and respond to volume for hours on end and then decides to go a lot louder and only play on one channel.

A power cycle or two of the V3 will 'fix' the problem.

Does this sound like the unit needs returning to Fosi?

Thank you.

 

[Joe Smith]

Yes!

 

[korgua]

I contacted Fosi support and they were asking me check the volume knob for obstructions, swap out speakers, swap out opamps as well as asking how I had the amp connected up. They said this is the first time they have seen this issue.

I can recreate the issue by turning off the amp, if I turn it back on, the left channel goes very loud, right channel nothing and the volume does nothing.

I am convinced the amp does have to be returned and it will be interesting to see how Fosi respond.

 

[Joe Smith]

One thought…swap your rca cables and see if problem stays the same?

 

[olds1959special]

After owning a Fosi ZA3 with it's flawed design (input sensitivity too low) and a totally useless Fosi P4 pre-amp, I will never buy a Fosi product again.

 

[Joe Smith]

Gee, I love all my Fosi gear, no problems! V3 stereo, P4 preamp, Q6 dac and a new product I’m trialing for them that may come out later this year.

 

[Joe Smith]

Gee, I love all my Fosi gear, no problems! V3 stereo, P4 preamp, Q6 dac and a new product I’m trialing for them that may come out later this year.

And good power supplies too.

 

[korgua]

One thought…swap your rca cables and see if problem stays the same?

I did try another set of cables and the same problem occured. The problem is very random....might not happen for a few hours. Music is never on more than 30% volume but when the problem occurs, the volume goes to a point that is too loud for me.

 

[korgua]

The whole AliExpress refund process is not smooth, despite asking to get the unit refunded, Fosi want to replace it....which then resets the timer for the seller to respond. The AliExpress policy clearly states if you are not 100% satisfied (I am about 5% satisifed), we've made the return/refund process super easy. Never mind, given I have time to waffle on here then I cannot grumble at letting the refund process to run its course.

 

[korgua]

I think it is helpful to other members to explain how poor Fosi support is. Their UK warehouse rejected my return on the 19th March, stating that I did not upload the tracking information on AliExpress. This is nonsense as the shipping and tracking was provided by AliExpress at the point AliExpress issued the return label on their portal. Since then, no one at AliExpress or Fosi are helping. After supplying all the photos of the package return (in Fosi wrapping), parcel in the post office and the rejection by Fosi, Fosi say I need to re-apply for a return through AliExpress and return the parcel. I reminded them that they refused the parcel and that the parcel has been lost in logistics since 19th March....they still said I need to re-apply for the return and ship the package to another warehouse.

I don't have problems with online orders the vast majority of the time, if I do, then they are resolved quickly and efficiently. 33 emails in, we are further away from resolution than we could be. I thought it might be a language barrier, but it is not. Fosi's tactic is simple, point the blame elsewhere thinking the customer will either give up or not succeed.

 

[TurtlePaul]

You have just speakers connected to the output and not a subwoofer too, right?

Sometimes similar issues happen when one of the negative legs of one of the speaker terminals is being grounded (on these chips, none of the speaker terminal are grounded).

When the amp detects that one of the pins is being grounded, it disables it. That will cut the volume substantially. The primary culprit is that subs with high level inputs do this and therefore subs with high level inputs don’t work with differential output amplifiers.

I suppose that a speaker, perhaps with a metal case sitting on something conductive, could also be made to ground the black terminal. This is less common.

 

[korgua]

You have just speakers connected to the output and not a subwoofer too, right?

Sometimes similar issues happen when one of the negative legs of one of the speaker terminals is being grounded (on these chips, none of the speaker terminal are grounded).

When the amp detects that one of the pins is being grounded, it disables it. That will cut the volume substantially. The primary culprit is that subs with high level inputs do this and therefore subs with high level inputs don’t work with differential output amplifiers.

I suppose that a speaker, perhaps with a metal case sitting on something conductive, could also be made to ground the black terminal. This is less common.

I only had speakers connected and the Fosi was returned, neither the original amp or the replacement, a Topping, are a problem.

 

[olds1959special]

I won't buy Fosi products because I've had too many problems with them in the past.