LYNEPAUDIO B049 Audio Switcher Review

[amirm]

If the results are so unusual that they cannot be reasonably explained, it could be prudent not to publish if the results are so far out of specification that they don't make sense.

There are plenty poorly designed noname products. There is no evidence that specs are real either.

 

[solderdude]

If the results are so unusual that they cannot be reasonably explained, it could be prudent not to publish if the results are so far out of specification that they don't make sense.

On the other hand, if you can't find them, maybe they can't find you.

The measurements seem to match what is found inside.
Using MOSFETS as source-followers on 5V will result in the measured response.

 

[KSTR]

The measurements seem to match what is found inside.
Using MOSFETS as source-followers on 5V will result in the measured response.

I'd think some electronics novice just read "MOSFETS can be used as switches / pass-gates" and hacked together a circuit without any further thought... alas, it's non-working by design, clearly visible from the gut shots.


Thus:

If the results are so unusual that they cannot be reasonably explained, it could be prudent not to publish if the results are so far out of specification that they don't make sense.

Before piling onto this thing, it should be determined if it is faulty or not.

70mV asymmetric clipping with an active 5V supply suggests something is wrong.

No, nothing is faulty, we simply overestimated the skills of the "designer".

I agree on the prudency part, though, looking at this thingy as a black box first.

 

[solderdude]

Saturation seems to occur around 1.5V, distortion just gradually increases from 70mW up to the knee around 1,5V.
This requires 4.3V voltage swing if the buffer was biased correctly (gate at around 3V DC ?)
I figure the Gate DC bias voltage is a bit too low, maybe at 1/2 voltage rail ?
Too much voltage drop across GS would then be resulting in the asymmetric behavior.
Chances are for most people the device would be usable up to 1.5V.
That said most DACs do 2V or even higher.

As said... I would try to run the device at 9V DC and if that did not work I would remove the buffers and bypass the buffer circuit.
I would not use a higher voltage given the 10V rated power supply caps. Well... assuming these aren't caps for the bias voltage otherwise 12V DC might be good enough for non critical usage (say a P.A. system)

When using it in a hifi system just remove the buffers and bypass the part where the circuit was. Just be careful when paralleling amps that the loud does not become too low in impedance for the connected source.

 

[tmtomh]

If the results are so unusual that they cannot be reasonably explained, it could be prudent not to publish if the results are so far out of specification that they don't make sense.

On the other hand, if you can't find them, maybe they can't find you.

The results have been corroborated by another owner with another example of the same unit.

Moreover, the review published here was the reason the other owner even tested their unit.

The alternative would be an indefinite - likely infinite in this case - delay in publishing the review, leaving the only online info on it what you can find while Googling: a bunch of recommendations of it from folks who have bought it and like the price and functionality but have never measured it and also have no idea that it’s an active device.

 

[kemmler3D]

If the results are so unusual that they cannot be reasonably explained, it could be prudent not to publish if the results are so far out of specification that they don't make sense.

On the other hand, if you can't find them, maybe they can't find you.

I think the results can be explained very reasonably. Low-end audio manufacturers often flat-out lie about specs. I am sure if you look around, you can find a few no-name "2000 watt" party speakers that run on 40w power supplies.

 

[dzerig]

I think the results can be explained very reasonably.

You understand I'm talking about a situation where the measurements are inconsistent with other units, right?

Obviously if the measurements are correct there is not lawsuit.

I'm not saying Amir's measurements are wrong or even suggesting it.

I'm simply pointing out that if they were wrong, and if there were damages, the fact that he reviewed a used unit makes him vulnerable to a lawsuit.

The results have been corroborated by another owner with another example of the same unit.

Moreover, the review published here was the reason the other owner even tested their unit.

The alternative would be an indefinite - likely infinite in this case - delay in publishing the review, leaving the only online info on it what you can find while Googling: a bunch of recommendations of it from folks who have bought it and like the price and functionality but have never measured it and also have no idea that it’s an active device.

Again, I do not doubt the test results are consistent with other units.

The alternative would not be an indefinite delay in the review ... the alternative would be, in the few instances where the data don't match to such a degree, to request a unit from the manufacturer, or try to buy one if funds avail.

If not, tell your readers and you have done at least some due diligence. Not a huge effort to cover your ass.

 

[kemmler3D]

the fact that he reviewed a used unit makes him vulnerable to a lawsuit.

In the US, everyone is vulnerable to lawsuits at all times, because anyone can sue anyone for any time for any reason, even fake reasons.

That said, reviewing a used unit or a new unit doesn't have any particular legal status I know of. There's no obligation on the part of reviewers to only review "good" units. He got a unit, he measured it, and he didn't lie about the unit or how he reviewed it. AFAIK (I'm not a lawyer) there's nothing in that where he could lose a case on the merits. You lose this type of case when you are negligent or flat-out lie about the unit. Beyond that reviewers have the right to speak as they please, whether the product is old, new, broken, or not.

A very good defense against negligence in this type of reviews (IMO) would be to offer to publish replies from manufacturers and/or re-test if they assert the unit is broken. Which Amir does consistently.

So whether this unit is broken or not is interesting for the readers, but is not necessarily relevant either way in a court case.

... the alternative would be, in the few instances where the data don't match to such a degree, to request a unit from the manufacturer, or try to buy one if funds avail.

If not, tell your readers and you have done at least some due diligence. Not a huge effort to cover your ass.

Not a crazy thought, but AFAIK the standard in the industry is to allow the manufacturer to respond, not to proactively assume the unit is broken and help them fix the review.

 

[dzerig]

Not a crazy thought, but AFAIK the standard in the industry is to allow the manufacturer to respond, not to proactively assume the unit is broken and help them fix the review.

AFAIK the standard in the industry is to buy units new or receive from manufacturer new, not solicit units from members of unknown condition.

Which I appreciate. The ability to send Amir gear to see how my favorite gear measures is one of my favorite parts of this site. I'm not criticizing anyone.

Just saying when you do so, you open the door to liability in ways you would not if you limited your reviews to brand new gear. There are ways to mitigate this liability of course. But my point is that Amir should be aware how this way of doing reviews puts him at slightly greater risk should "a very unlikely sequence of events occur".

 

[KSTR]

I figure the Gate DC bias voltage is a bit too low, maybe at 1/2 voltage rail ?
Too much voltage drop across GS would then be resulting in the asymmetric behavior.

I now had a closer look and it looks like it really actually simple source follower. The MOSFET is an AO3402 which has about 1V Vgs, so the biasing should be ~1V above mid supply, so 3.5V in this case, for the source to bias at mid supply. With the current bias divider gate is only at 2.86V and that is too low.
Therefore, just as you said, a higher supply like 9V would fix the gross distortion... but it will be still quite bad even without the clipping.

!! But the elephant in the room is that there seem to be no output DC blocking capacitors, which means the unit puts out like 2V DC voltage !!
And if you pull down the outputs to GND the MOSFETS go into full conduction, shorting out the supply (or frying themselves).

Therefore...

When using it in a hifi system just remove the buffers and bypass the part where the circuit was. Just be careful when paralleling amps that the loud does not become too low in impedance for the connected source.

... is the only sane advice one could give.

 

[kemmler3D]

AFAIK the standard in the industry is to buy units new or receive from manufacturer new, not solicit units from members of unknown condition.

Which I appreciate. The ability to send Amir gear to see how my favorite gear measures is one of my favorite parts of this site. I'm not criticizing anyone.

I don't disagree.

Just saying when you do so, you open the door to liability in ways you would not if you limited your reviews to brand new gear.

I think this is incorrect, unless the reviewer misrepresents where they got the unit. Which I have never seen Amir do.

Let me put it plainly: There is no law against reviewing used (or even broken) equipment, nor any precedent I'm aware of. Therefore, no change whatsoever in one's legal liability.

There are ways to mitigate this liability of course. But my point is that Amir should be aware how this way of doing reviews puts him at slightly greater risk should "a very unlikely sequence of events occur".

Again, all the reviewer has to do to avoid legal liability is not lie. They don't even have to get the facts right, they just have to make a good faith effort to do so.

If Amir took a broken unit and claimed it was new, that might create some real liability for him. If he takes a unit from a member, and (as he does) explain that he's not sure it's not broken - I see that as 100% above board.

My previous job was heading up marketing and product for a small consumer audio company. I've had products reviewed where I thought they got some of the facts wrong. I never considered suing the reviewer for 2 reasons. 1) I knew I would lose the case if it went to court and 2) the harm to my brand's reputation that comes from hassling reviewers would be way worse than just having a mediocre review out there.

Case in point, Eric Alexander's massive self-inflicted PR catastrophe. That outcome was 100% predictable if he knew anything about anything.

 

[JSmith]

Let's just call a spade a spade here... this thing is broken and garbage. Further testing will not change this... simples.


JSmith

 

[nagster]

Thank you to the owner and amirm.
It has become clear that it is better to avoid them in any case. Average performance would have been enough, but it is a shame as they are cheap and look useful.
If don't know about them, might buy them without knowing, and beginners in particular might end up with terrible sound and become disillusioned with audio.
There are few people who seriously review cheap equipment, few reliable reviewers, few reviewers who will honestly write bad results, and few places where bad results can be published.
It's fun to see SOTA's progress, but I hope you will continue to provide important and valuable reviews even in this general price range.

 

[F1308]

We can have a scale from

Great
Superb
Ultra Performant
Perfect+
Godlike performance

then no one can complain.

“Great” products may not immediately kill or maim the reviewer , thats the secret threshold for that ..

I just met this regarding wines...

About The Scores
*Products deemed unacceptable (receving a rating below 80 points) are not reviewed.

98-100
Classic
The Pinnacle of quality

94-97
Superb
A great achievement

90-93
Excellent
Highly recommended

87-89
Very Good
Often good value; well recommended

83-86
Good
Suitable for everyday consumption, often good value

80-82
Acceptable
Can be employed

 

[Mnyb]

I just met this regarding wines...

About The Scores
*Products deemed unacceptable (receving a rating below 80 points) are not reviewed.

98-100
Classic
The Pinnacle of quality

94-97
Superb
A great achievement

90-93
Excellent
Highly recommended

87-89
Very Good
Often good value; well recommended

83-86
Good
Suitable for everyday consumption, often good value

80-82
Acceptable
Can be employed

Suitable for everyday consumption ? Are we down at bum wines then ? thunderbird or night train and similar.

 

[amirm]

AFAIK the standard in the industry is to buy units new or receive from manufacturer new, not solicit units from members of unknown condition.

This was a brand new unit, not used.

 

[tmtomh]

This was a brand new unit, not used.

Well, that settles that then. If it by chance came defective from the factory, that's unfortunate but still on the manufacturer.

And when we combine this important bit of info with the fact that another member here got essentially the same result when more than one output was enabled - when the unit was acting as a distribution amplifier, which presumably is the entire reason it has active components in the first place - I think it's pretty strong evidence that this is just how this unit functions.

 

[F1308]

Suitable for everyday consumption ? Are we down at bum wines then ? thunderbird or night train and similar.

The moral of the story is obvious.
Just needs a little tweek to match the audio sphere.