In this review, we will get into the details of the Fosi Audio new AB speaker switcher the LC30, with it’s gorgeous VU meters providing a very nice retro look, lets see if you have room for a “switcher” in your home setup.


Fosi Audio LC30 - A bit of Retro nostaglia

Fosi Audio new kickstarter project the LC30 is a distinctively stylish and functional device. This review delves into the LC30, a unit that not only caters to the pragmatic needs of audio enthusiasts with might want to do a bit of AB switching but also appeals to the retro aesthetic with its visually captivating VU meters.

Build quality

The LC30 comes in the typical Fosi Audio box: FOSI-LC30-box.jpeg

Once opened you get a manual a nice remote a usb cable to power the LC30 and of course the LC30 itself: LC30-box.jpeg


Key features include the innovative A/B switching capability, allowing seamless transitions between amplifiers and speakers.

The front of the LC30 features a few useful buttons: LC30-FRONT.jpeg

So on the left you can switch between speakers and on the left you can switch between amplifiers. These work as expected and a little indicator shows with speaker and amplifiers is currently active.

The On/Off switch also doubles as a toggle for different levels of brightness in the lights behind the VU meters, allowing 3 different levels of brightness. I found during the day the highest level was fine but at nighttime I lowered it down to the minimum level. This can be controlled with the supplied remote. I thought different levels of lighting were a nice feature.

The other button which looks like a Volume control is actually the control over the sensitivity of the VU Meters, you turn it ‘down’ i.e. to the left if you pushing lots of power through to your speakers and you turn it ‘up’ when you have easy to drive speakers that do not need much power. But as you will read later in the review I do wish it was a little more sensitivity range.

Here is a short video from Fosi Audio demonstrating the LC30:


I found the provided remote to be excellent, with a sensible button layout:

LC30-Remote Medium.jpeg

Blind test withing the LC30

With the Remote I especially liked the (SPK) and especially the (AMP) buttons - as these are toggles which are crucial for some blind testing. For example, I was do some A/B testing between the Fosi Audio ZA3 and another similar class D amplifier. I simple volume matched both amplifiers and then covered up the light indicator on the front of the unit (so I could not see which amplifier was ‘active’), and then I pressed the Amp button a random amount of times and then sit back and listen to both amplifier with the same music playing on both (via 2 WiiM Streamers with their audio ‘synced’ ) toggling between each amplifier but not knowing which one was feeding my speakers. When I was satisfied that one sounded different than the other I would ‘reveal’ was it Amp A or Amp B by removing my cover.


While in the past few weeks I have been really enjoying the LC30, I did notice 2 minor issues:

The limited range of the sensitivity dial

In my experience, with some of the speakers I tried with the LC30 (such as my very easy to drive Q Acoustics 3020i speakers) in my small listening room, I found that even at the highest sensitivy level I could hardly get the dials to move without turning the volume up considerable.

Here is what level of movement when just playing music at a normal volume: LC30-anim.gif

My ultimate plan for the LC30 is my larger listening space (as I have multiple Amplifiers and Speakers in that space) and this was an issue with those speakers.

The lack of automatic power-on

My other minor issue with the LC30 is related to how it powers up, it does not automatically start passing the audio signal on startup (probably to protect the speakers) but in my use case I have a trigger turning on my amplifier and the LC30 so when I start to play music on the amplifier it ‘wakes up’ but the LC30 does not pass the signal unless I switch it ‘On’ via the remote or the button on the front of the unit. I since switched to leaving the LC30 plugged in with power all the time.


The LC30 has been designed to be compatible with various types of amplifiers, including Class A, B, AB, D, and tube amplifiers. It also features built-in load protection, ensuring amplifiers are not left without a load. It’s fully isolated design for all channels minimizes mutual interference, enhancing the listening experience.

Sound quality:

Since it’s job is really just a pass through of the speaker signals it should not alter the sound signature at all. It is not an amplifier or a DAC/ADC so the only 2 issues you might run into would be the possible introduction of distortion and a max load problem. While I would probably not drive crazy speaker loads through the LC30 as far as distortion is concerned I did not measure any noticeable difference in distortion when routing my speaker cables through the LC30 as opposed to directly between my amplifiers and the speakers.


I gave the LC30 a pragmatic audio rating of 4 - it provides that retro VU meter appeal with minimum fuss and with the ability to A/B switch between Speakers and Amplifiers a very useful features for any audiophile.


The LC30 is ideal for both brightening up your home audio experience with a nice retro styling but also allows a nice switching capability. Despite the issue with the VU meter not been very responsive with my speakers I
found myself really enjoying the LC30 and would recommend it to anyone.