New Fosi Audio N3 - Compact Bluetooth Receiver/Headphone Amp
Oct 15, 2023 at 5:45 PM Thread Starter Post #1 of 6

JEnglishSmith

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Fosi Audio recently sent me a fairly new product to try out, their N3 bluetooth receiver/headphone amp. It's a bit of a niche product but I was interested to review one after seeing the photos. It is currently available on "that auction site" for $60, but I don't see it yet on Fosi's main website.

The device can be used in two ways: 1) to receive a BT signal and amplify it to a headphone, or 2) to receive a line in signal and amplify it to a headphone. While the box says it is a "DAC and headphone amplifier," I think it is in fact just a BT receiver/amplifier.

It's very compact - 3.5" x 2" x .5" - case is black anodized. Weight is 40 grams per Fosi's data. Battery life is about 10-12 hours, charging is via a USB-C port on the bottom of the unit using a normal 5v/1a phone charger (not supplied). Fit and finish is nice, with a few caveats noted below.

Sound quality using my normal earbuds or headphones is good. Volume control is via a rotary thumbwheel (see below). They do not list recommended impedances, but power would be OK for low to medium impedance products. There is switchable GAIN and BASS on the main control side of the unit. They both work well. There is not a large change from low to high gain. The bass boost is a nice amount. It reminded me of the nice bass jump ("1" boost) available on my old Fiio E7 Dac/Amp. This unit reminded me a bit of the old Fiio in appearance and it's just a tad smaller.

Pairing was easy with either my iPhone or a laptop. BT reception was good, I have an old 1900s house and it could not get through multiple plaster walls upstairs, but the line of sight transmission to 20-25 feet was good.

Packaging is basic, just the device, short manual and a USB-C charging cable. A foam insert in the box protects the device for shipment.

Other Pros:
1) Nice compact size.
2) Fosi picked up the ORANGE color from the recent V3 amp knob and uses that for the main POWER button on this unit. Nice pop of color.
3) Battery LEDS are easy to see and understand.
4) Nice fit and finish overall.
5) Setup is very easy.
6) It has sufficient power to work with normal low to mid impedance headphones/IEMs.

Cons:
1) There are NO volume markings on the volume thumbwheel or case. I've called this out to Fosi as something they should change next time around. It would be pretty easy to mis-remember the way the knob turns and blast your ears if not cautious when using the unit.
2) When no music is playing, I clearly hear a soft hum (like a "carrier frequency") from the BT signal with my headphones. It's not noticeable when music is playing, but it's enough to affect sound quality. Not present when using the AUX IN.
3) The plastic window with the Fosi logo serves no function whatsoever, it is just for show, and is very scratchable. I thought that was where I'd see something lit up or a volume level. Wrong! It's just a weird design thing and will scratch over time.
4) Screws on the back side detract a bit from appearance, but it would make it easier to open the case if need be - but for the price point, can't imagine repairs are going to occur, really.
5) Could really benefit from a rubber sleeve like my old Fiio DAC had to protect the finish and make it less likely to slip around on a table, or fall out of a shirt pocket.

I appreciate Fosi sending this to me and letting me test out. In general, I feel this is a pretty niche device, good to use if you specifically need to walk around with headphones and you are willing to use basic Bluetooth as the source.

Photos:

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Dec 27, 2023 at 10:23 PM Post #2 of 6
Fosi Audio recently sent me a fairly new product to try out, their N3 bluetooth receiver/headphone amp. It's a bit of a niche product but I was interested to review one after seeing the photos. It is currently available on "that auction site" for $60, but I don't see it yet on Fosi's main website.

The device can be used in two ways: 1) to receive a BT signal and amplify it to a headphone, or 2) to receive a line in signal and amplify it to a headphone. While the box says it is a "DAC and headphone amplifier," I think it is in fact just a BT receiver/amplifier.

It's very compact - 3.5" x 2" x .5" - case is black anodized. Weight is 40 grams per Fosi's data. Battery life is about 10-12 hours, charging is via a USB-C port on the bottom of the unit using a normal 5v/1a phone charger (not supplied). Fit and finish is nice, with a few caveats noted below.

Sound quality using my normal earbuds or headphones is good. Volume control is via a rotary thumbwheel (see below). They do not list recommended impedances, but power would be OK for low to medium impedance products. There is switchable GAIN and BASS on the main control side of the unit. They both work well. There is not a large change from low to high gain. The bass boost is a nice amount. It reminded me of the nice bass jump ("1" boost) available on my old Fiio E7 Dac/Amp. This unit reminded me a bit of the old Fiio in appearance and it's just a tad smaller.

Pairing was easy with either my iPhone or a laptop. BT reception was good, I have an old 1900s house and it could not get through multiple plaster walls upstairs, but the line of sight transmission to 20-25 feet was good.

Packaging is basic, just the device, short manual and a USB-C charging cable. A foam insert in the box protects the device for shipment.

Other Pros:
1) Nice compact size.
2) Fosi picked up the ORANGE color from the recent V3 amp knob and uses that for the main POWER button on this unit. Nice pop of color.
3) Battery LEDS are easy to see and understand.
4) Nice fit and finish overall.
5) Setup is very easy.
6) It has sufficient power to work with normal low to mid impedance headphones/IEMs.

Cons:
1) There are NO volume markings on the volume thumbwheel or case. I've called this out to Fosi as something they should change next time around. It would be pretty easy to mis-remember the way the knob turns and blast your ears if not cautious when using the unit.
2) When no music is playing, I clearly hear a soft hum (like a "carrier frequency") from the BT signal with my headphones. It's not noticeable when music is playing, but it's enough to affect sound quality. Not present when using the AUX IN.
3) The plastic window with the Fosi logo serves no function whatsoever, it is just for show, and is very scratchable. I thought that was where I'd see something lit up or a volume level. Wrong! It's just a weird design thing and will scratch over time.
4) Screws on the back side detract a bit from appearance, but it would make it easier to open the case if need be - but for the price point, can't imagine repairs are going to occur, really.
5) Could really benefit from a rubber sleeve like my old Fiio DAC had to protect the finish and make it less likely to slip around on a table, or fall out of a shirt pocket.

I appreciate Fosi sending this to me and letting me test out. In general, I feel this is a pretty niche device, good to use if you specifically need to walk around with headphones and you are willing to use basic Bluetooth as the source.

Photos:

JEnglishSmith,
A nice review on the Fosi N3. I'm really surprised you haven't gotten any replies as people are missing out on a great sounding portable headphone amp that is now on sale at Amazon for only $39.99. I've only used it with the Bluetooth connection and I'm blown away at how good it sounds with all of my headphones. I'm not getting that soft hum (like a "carrier frequency") from the BT signal that you mentioned. When playing FLAC files from my computer using Bluetooth, I don't hear any hum or hiss. I paused the playback and turned the volume all the way up on the Fosi N3 and I still couldn't hear any hum or hiss just dead silence. I've tried it with Sennheiser HD 58X , HD 598 Cs, and Hifiman He400se and it is able to drive all of them when playing FLAC files from my computer (Asus Strix Z270E Gaming) using a Bluetooth connection with out any problems. I found the Fosi N3 was able to drive my 150 ohm HD 58X headphones to loud levels with no audible distortion with the volume control turned half way up and it sounded great. The Hifiman He400se planar headphones are known to be hard to drive but the Fosi N3 had no problems driving them to a loud listening level with volume control turned up about half way and they also sounded great. I also found the bass boost and treble boost buttons to be very useful; they only add a slight boost which makes them very useable and I leave the bass boost on all of the time as it only seems to boost the lower frequencies and does improve the over all sound. I just bought some new Focal Elegia headphones and I also ordered the Dekoni Custom Series Stellia-style replacement earpads for it so I'm excited to see how they will sound with the Fosi N3 as well as with my Asgard 3 and Bifrost 2 DAC. I will give an update here once I receive them.

It would be nice if some other Fosi N3 owners would post their opinions here on the Fosi N3 and comment on whether you can hear any hum during Bluetooth playback. I feel like this is a bargain that is flying under the radar that more people should know about. For $39.99 this is a steal, I spent more than twice as much as that just for Dekoni earpads.
 
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Dec 28, 2023 at 12:35 PM Post #3 of 6
Yeah, that's a good price and an even lower price than a month ago! I will try mine again, have not used in a while. See if anything different re that carrier level sound. I have noticed on mine, also, the battery drains off quickly even if the unit is switched off, you have to recharge it before using it again. Does yours do this?
 
Dec 28, 2023 at 12:52 PM Post #4 of 6
Yeah, that's a good price and an even lower price than a month ago! I will try mine again, have not used in a while. See if anything different re that carrier level sound. I have noticed on mine, also, the battery drains off quickly even if the unit is switched off, you have to recharge it before using it again. Does yours do this?
No mine doesn't do that the battery doesn't drain off when it is off.
Maybe you should buy another one now that it is so cheap and retest it.
Perhaps you can return your first one for a refund or get it replaced under warranty.
I think that it actually does have a built in DAC as the Bluetooth signal is digital and has to be converted to analog.
Found this information about DACs

https://www.head-fi.org/threads/wireless-headphones-dacs.878308/#:~:text=in general: yes, the transmission is digital and,the lossy transmission standard (SBC, LDAC, AAC, AptXHD)
 
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Dec 28, 2023 at 4:26 PM Post #5 of 6
Ah! I was never 100% clear whether the BT signal is digital or not. Makes sense though, then it would have an internal DAC.

Fosi sent me the device for free, I will prolly just keep this one and use occasionally. If I was going to use it often, like you, I would return or get a new one...

Glad to hear your battery is better than mine. I recharged mine fully two days ago, turned off, checked just now and it's sitting at three LEDs. Weird, some power drain when it is off or just a weak battery?
 

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