Fosi Audio LC30 Speaker/Amp Switcher & Meter

[Sjkrabbe]

So I am not the only one on this forum listening to Wollenweider?

No you are not I have had nice times with his records since the first album came out in first half of the 1980s. Saw him live in concerts back then as well

 

[Sjkrabbe]

Apples and pears. Having said that, TC electronic Clarity M seems to be good if you are in need of:

The CLARITY M provides a comprehensive set of precision tools essential to the success of any audio producer. Ideally suited to stereo and 5.1 mixing, mastering and post-production,...

TC Electronic | Product | CLARITY M

www.tcelectronic.com

I use the TC clarity meter on a every day basis and it is SO great. I use it when Im mixing Radio broadcasts. When you have first tried it there is no going back. But it has only digital input, AES/spdif

 

[solderdude]

But, what this device is supposed to be designed for ?

People that like to see nice swinging needles and/or need a speaker or amp switcher.

Meters not calibrated? Rated poor. Guess I‘m too much German engineer.

They can't be calibrated as it only measures a voltage and not power.
and ... if you calibrated it to a certain speaker impedance it still would not show the correct power value.
and ... even if you calibrated it at a certain power level the scale is incorrect anyway so an indicated power level at a substantial different deflection than what you calibrated it to would still be incorrect.

The meter is just for fun (as mentioned by Amir in the review).
Power scale and dB scale are not 'matching' either so 1 or both scales are incorrect.
You could use it as an amp or speaker switcher, but not for >250W amps.
The 'safety load' of 390 ohm for the not connected amp can hardly be called a correct load.

It looks nice, needles swing up and down. That's what people will be buying it for while believing it truly indicates output power.

 

[beagleman]

People that like to see nice swinging needles and/or need a speaker or amp switcher.

They can't be calibrated as it only measures a voltage and not power.
and ... if you calibrated it to a certain speaker impedance it still would not show the correct power value.
and ... even if you calibrated it at a certain power level the scale is incorrect anyway so an indicated power level at a substantial different deflection than what you calibrated it to would still be incorrect.

The meter is just for fun (as mentioned by Amir in the review).
Power scale and dB scale are not 'matching' either so 1 or both scales are incorrect.
You could use it as an amp or speaker switcher, but not for >250W amps.
The 'safety load' of 390 ohm for the not connected amp can hardly be called a correct load.

It looks nice, needles swing up and down. That's what people will be buying it for while believing it truly indicates output power.

Right.....no way to really "Show" wattage as is is merely a calculation based on varying speaker load by frequency.

You CAN show wattage accurately for a single point at one frequency with a test tone though, but what fun is that...Is that kinda like what Amir does....I mean testing and all??

 

[solderdude]

You CAN show wattage accurately for a single point at one frequency with a test tone though.

With this meter you could do that if the impedance at that frequency was known. Unfortunately it can only be correctly calibrate at a certain level but since the scale is not correct either indications at the same frequency would not be correct.

Sadly this device can not be used as a measurement device. Only as amp/speaker selector with some 'swinging needles'.

 

[badie]

i did some videos comparing
Accuphase E-405 VU meters to the LC30´s ones

You can watch them in my post here on ASR: Post in VU Meter Amp/Speaker Selector
(in just a minute they show more than words)

My full written review in German: Review of FOSI LC30 on hifi-forum.de

Conclusion:
Useful for comparing Amps.
Not useful for comparing Loudspeaker (as there is no built-in attenuator)
Nice looking VU Meters with a nice classic tint/glow.
Meters are just for fun AND If you want to have those dancing needles you will have to set sensitivity each time you change listening volume (Small changes result in no more needles or needles maxed out).

But Fosi is somehow on the way to make a better unit ... let´s see what their next step is.

 

[beagleman]

With this meter you could do that if the impedance at that frequency was known. Unfortunately it can only be correctly calibrate at a certain level but since the scale is not correct either indications at the same frequency would not be correct.

Sadly this device can not be used as a measurement device. Only as amp/speaker selector with some 'swinging needles'.

But, again, NO "Watt Meter" can show actual wattage, as they all only show voltage.

I still find it good to show "relative" levels of loudness or volume.
But through some experimenting, you can at least derive an idea of the power and loudness of one particular set up if one takes some time to calibrate it to known values.

 

[EddNog]

No you are not I have had nice times with his records since the first album came out in first half of the 1980s. Saw him live in concerts back then as well

and @renaudrenaud are you guys talking about him: https://www.vollenweider.com/

My dad introduced me to his music years ago and I enjoy a bit of his work on my playlists. Wonderful music, dreamy landscapes, very relaxing. In particular songs from the White Winds and Dancing with a Lion albums.

Moving back on topic--am I the only one who finds it amusing that this little, "lowly," device is, "separating the men from the boys," with how it affects the higher-caliber amps like Purifi and Topping Bx00, but not the more pedestrian amps like ZA3?

-Ed

 

[fedocable]

I could use something like this in my system. I use my main speakers (Cabasse Altura Riva) with both my stereo amp and my home theatre. When I want to switch, I just unplug a set of cables from the speakers and plug the other one -making sure both amps are off and even unplugged from the power. So if this unit measured A+, it would really come in handy. But, placebo or not, I don’t like the idea of adding the slightest distortion, just to avoid getting up of the coach and spending 15 seconds switching the cables.

 

[Ralph_Cramden]

what device is that on top of the RME?

GitHub - retired-guy/WiiM-VU: VU Meter Display for WiiM

VU Meter Display for WiiM. Contribute to retired-guy/WiiM-VU development by creating an account on GitHub.

github.com

 

[beeface]

GitHub - retired-guy/WiiM-VU: VU Meter Display for WiiM

VU Meter Display for WiiM. Contribute to retired-guy/WiiM-VU development by creating an account on GitHub.

github.com

Very cool. Thank you

 

[OldManMatt]

Not my cup of tea but seems to be fairly transparent if your wires/cables are properly attached. I personally would just hook one set of speakers only & use it for the aesthetics instead of switching.

Outside of being a switcher it could be helpful if wanting to compare a 2 sets of speakers. For an amp switcher I'd like something with an RCA or XLR input with variable outputs.

Does anyone know of a transparent switcher device with one or 2 stereo inputs...2 or more stereo outputs? Not banana plugs of course.

 

[fedocable]

Honestly, the second set of cables doesn’t make the setup any uglier, so I don’t mind it at all. But more importantly, even though I lurk this site a lot and use Amir reviews as reference for any audio purchase, I don’t understand the first thing about load, impedance and etc. So I don’t know how safe it would be to use this with my tube amp (a Unison Research Simply Italy). According to an Amazon user review, at least, it’s not a great idea:
“Does not provide protective load for both amps.
If you are using a tube amp you will have to be very careful how you set this up.
Protective load is 250ohm not 390ohm.
Seems OK for SS amps but not recommended for tube amps.”

Edit: If I wanted a switch, I’d probably be better off with the Neohipo ET30, which measured great in Amir’s review. Again according to an Amazon comment, this one is tubes friendly:
“This unit fulfils its main purpose for me by allowing seamless switching between my tube amp and solid-state amp, since it still sends a small load to the tube amp when not selected, this eliminates the risk that comes with not feeding a signal to powered-on tubes.”

 

[pma]

Some pics from Fosi marketing material on Amazon;

Low current relays, would be interesting to see reliability.

 

[solderdude]

IME with amplifier repair (for 2 decades) most issues with crackling sound are caused by output relays, A-B switches in amps and input switches as well as volume controls and even switching headphone sockets rather than the actual electronics.
As @pma said... not all relays are equally suited for switching speakers. Most new relays will probably work fine the first few years though before they slowly start to increase contact resistance, even in a non-linear way.

 

[Arvind]

Honestly, the second set of cables doesn’t make the setup any uglier, so I don’t mind it at all. But more importantly, even though I lurk this site a lot and use Amir reviews as reference for any audio purchase, I don’t understand the first thing about load, impedance and etc. So I don’t know how safe it would be to use this with my tube amp (a Unison Research Simply Italy). According to an Amazon user review, at least, it’s not a great idea:
“Does not provide protective load for both amps.
If you are using a tube amp you will have to be very careful how you set this up.
Protective load is 250ohm not 390ohm.
Seems OK for SS amps but not recommended for tube amps.”

Edit: If I wanted a switch, I’d probably be better off with the Neohipo ET30, which measured great in Amir’s review. Again according to an Amazon comment, this one is tubes friendly:
“This unit fulfils its main purpose for me by allowing seamless switching between my tube amp and solid-state amp, since it still sends a small load to the tube amp when not selected, this eliminates the risk that comes with not feeding a signal to powered-on tubes.”

Amir has not tested Neohipo ET30 for switching.

 

[MaxwellsEq]

Moving back on topic--am I the only one who finds it amusing that this little, "lowly," device is, "separating the men from the boys," with how it affects the higher-caliber amps like Purifi and Topping Bx00, but not the more pedestrian amps like ZA3

I found it interesting as well. What it seems to demonstrate is that low distortion at very high power requires well designed connectors which are clean, well made, properly plugged in and low impedance (and not ferromagnetic). If you don't have this, you get unexpected increases in distortion at the higher powers. However, these increases in distortion are probably not audible. The more "pedestrian" designs are less powerful and have higher intrinsic distortion, which again is probably not audible.

 

[Old_School_Brad]

Wow, everyone bashing the meters??

I think "We all know" there is virtually no way to make an actual accurate "Power" meter, as speakers are not resistive loads.
But meters like this, beyond being "Fun", are a nice way to have a relative "idea" of how loud or how much volume of music....to criticize it seems a bit silly.

AMM-1

The Audio Multimeter and Handheld Dyno. Measure TRUE amplifier power! Measure impedance of speaker boxes. Measure voltage drops, and much more! The purpose of this tool is to enable the user to: Measure True Amplifier Power output into any load reactive or resistive Measure Common DC...

damoreengineering.com

 

[fedocable]

Amir has not tested Neohipo ET30 for switching.

Good point, he just measured the impact of the VU meter on the amp. I’ll definitely stick with my manual switching method. If it ain’t broke…

 

[beagleman]

AMM-1

The Audio Multimeter and Handheld Dyno. Measure TRUE amplifier power! Measure impedance of speaker boxes. Measure voltage drops, and much more! The purpose of this tool is to enable the user to: Measure True Amplifier Power output into any load reactive or resistive Measure Common DC...

damoreengineering.com

Just add 2 of those at $467 each and you are set