Donner EM1 Portable IEM Amp Review

[amirm]

This is a review and measurements of the Donner EM1 battery operated, balanced input, portable IEM amplifier. It was kindly sent to me by a member and is on sale for US $47.

As noted, this is a very unique device. The USB connection you see is for charging the internal battery (there is no DAC). There is a belt clip for that obvious functionality. Input is combo XLR/TRS:

The case looks like is made out of metal but it is plastic. Still, everything feels good especially at this price. And the plastic helps keep the weight down.

If you are not familiar with Donner, they are the distributors are budget/high value musical instruments and accessories.

Donner EM1 Measurements
I am going to show a subset of our usual measurements as it is enough to understand the capabilities of the device. On that front, I was disappointed that its input would clip at 4 volts. You could crank the volume to minimum and it was still clipping. You can see this in the 300 ohm power sweeps:

If the input had not clipped, you would not see the earlier clipping with half volume level. Power output is quite modest. As expected, you do get more power with 32 ohm load:

Likely enough to drive most IEMs. Alas, the noise is not low as seen above and more specifically below:

So best not use a sensitive IEM.

Conclusions
The EM1 is quite a unique device and sold at very low price especially given the included battery. Performance is not great with early clipping of the input and high noise floor. Can we complain about these at such pricing? I am not sure. I let you decide.

Personally, I would look for something else but you could decide otherwise.

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As always, questions, comments, recommendations, etc. are welcome.

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[Michael Fidler]

I'm reminded that in order to have a decent SNR, you need to have a strong signal power against the thermal noise power of the resistances that signal operates against in the circuit. You can have either low power consumption, or low SNR, but not both...

Having said that, it looks good for the price, so rated fine. I'm sure it'll be useful to quite a few people.

 

[ObjectiveSubjectivist]

Whats the use case for this thing?
Just asking, monitoring while being "in the field"?

 

[Michael Fidler]

Whats the use case for this thing?
Just asking, monitoring while being "in the field"?

Checking connections while setting up big installations, monitoring a feed on the fly...

 

[AudioSceptic]

I'm reminded that in order to have a decent SNR, you need to have a strong signal power against the thermal noise power of the resistances that signal operates against in the circuit. You can have either low power consumption, or low SNR, but not both...

Having said that, it looks good for the price, so rated fine. I'm sure it'll be useful to quite a few people.

I'm not sure. Although it's small and light, it's still large compared with, say, the Apple Headphone Adapter, which performs pretty well for only about £/$9 and is a tiny thing. OK, it has less power, but it's enough for the IEMs I use.

 

[Michael Fidler]

I'm not sure. Although it's small and light, it's still large compared with, say, the Apple Headphone Adapter, which performs pretty well for only about £/$9 and is a tiny thing. OK, it has less power, but it's enough for the IEMs I use.

Sure, but maybe these have different intended use cases? The big feature on this, to my mind at least, appears to be the balanced input (which will certainly also accept TS/instrument inputs as well). I could see this being handy for monitoring/checking balanced lines on the go, or as a last-minute fix for a monitoring situation in a portable/professional setting?

 

[AudioSceptic]

Sure, but maybe these have different intended use cases? The big feature on this, to my mind at least, appears to be the balanced input (which will certainly also accept TS/instrument inputs as well). I could see this being handy for monitoring/checking balanced lines on the go, or as a last-minute fix for a monitoring situation in a portable/professional setting?

Maybe, but wouldn't someone using balanced want something much better for a few more $/£?, assuming of course that whatever feeds it doesn't already have a similar output built-in?

 

[Michael Fidler]

Maybe, but wouldn't someone using balanced want something much better for a few more $/£?, assuming of course that whatever feeds it doesn't already have a similar output built-in?

If you're running around installations, you'd probably want something small and cheap (doesn't matter much if it gets zapped or lost), though. Pro sound guys aren't audiophiles; they're tradesmen. They just want quick solutions that aren't massively expensive, prioritise 'good-enough' + reliability over quality, and allow them to get the job done with a minimum of fuss. I could see how something like this would make a welcome rattle to the bottom of a toolbox.

 

[AudioSceptic]

If you're running around installations, you'd probably want something small and cheap (doesn't matter much if it gets zapped or lost), though. Pro sound guys aren't audiophiles; they're tradesmen. They just want quick solutions that aren't massively expensive, prioritise 'good-enough' + reliability over quality, and allow them to get the job done with a minimum of fuss. I could see how something like this would be a welcome rattling to the bottom of a toolbox.

OK, you've got me! ;-)

 

[renaudrenaud]

Whats the use case for this thing?
Just asking, monitoring while being "in the field"?

Waste your time waiting for the true one.

 

[ObjectiveSubjectivist]

Waste your time waiting for the true one.View attachment 474917

Lol

 

[pieterv1]

Whats the use case for this thing?
Just asking, monitoring while being "in the field"?

It's just a no-fuss personal IEM amplifier, mostly aimed at live musicians. Especially those who don't move around too much on stage - drummers, keyboard players. They don't need a wireless solution. It's a utility thing mostly. We don't care about having the absolute best sound quality and lowest noise floor. We have other things to concentrate on

Not sure how I feel about the built-in battery though. It's nice to be able to just hot-swap AA's or 9v's.

 

[Multicore]

Whats the use case for this thing?

Monitors for musicians in a stage performance setting. That's where we got the term IEM from. In-ear as opposed to the old wedges on the stage floor.

 

[beefkabob]

From their site:

• High power: High power of headphone amplifier suited for high impedance professional headphone, make sure there is enough volume in noisy surroundings. (Don't support microphone)
• Professional in-ear monitor: Outstanding technical, sonic characteristics, high audio reproduction and no audio rendering for professional personal in-ear monitor.
• Practical interface: XLR and TRS input connector with locking mechanism, Stereo/mono source switch depending on cable connection
• Strong endurance: Runs up to 12-hour long life Li-ion battery. Power and battery charging control with Led indicators
• Easy to carry: Solid metallic belt-pack clip,High-tech, compact and portable designs for taking everywhere

Also all kinds of crappy sales offers. A spinning wheel of discounts for your email. A little gift box that bounces to bring it up:

This is a company I'd stay away from.

 

[SuicideSquid]

Whats the use case for this thing?
Just asking, monitoring while being "in the field"?

It's for on-stage monitoring for live performances. You unplug the floor wedge and plug the monitor XLR directly into this little guy, clipped to your belt, and then you can hear the stage mix in your IEMs without having to spend $1,000 on a wireless monitoring setup.

This is my unit, I have a couple of them, for this application they work really well. But you're not really concerned about noise floor because you're in a very noisy environment.

 

[SuicideSquid]

It's just a no-fuss personal IEM amplifier, mostly aimed at live musicians. Especially those who don't move around too much on stage - drummers, keyboard players. They don't need a wireless solution. It's a utility thing mostly. We don't care about having the absolute best sound quality and lowest noise floor. We have other things to concentrate on

Not sure how I feel about the built-in battery though. It's nice to be able to just hot-swap AA's or 9v's.

It charges by USB-C and in my experience lasts about 10 hours on a full charge. I just plug it in the day of a performance for a bit and it's great.

 

[sealman]

Definitely a use case I am not familiar with.
As described by several people above it seems absolute fidelity is not needed for it's intended use so I voted fine.

 

[kemmler3D]

Yes, this seems like an affordable way to get the job done on stage. Outside of that context, I think useless.

You're going to run XLR from your desktop DAC (which 99% already has a better HPA in it) just to get SNR in the 60s? No sir, I don't believe I will.

This is just a cheap & cheerful way to do live monitoring, I think. As far as that goes, seems fine.

 

[Robbo99999]

Seems like a pointless device to me. Ok, so it could be used in the professional environment as other people have said - ok a niche product, MEH.

 

[SoundsGood2Me]

I get the use scenario but can someone please explain how Amirm took stereo measurements on something with a single XLR input?

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