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4 Channel Headphone Amplifier
Fosi Audio PH04 is a 4-channel amplifier that features 4 independent stereo high-power amplifier sections with separate volume knobs for each output allowing flexible control for different headphones or speakers.
Portable and Durable Metal Exterior
Portable and durable metal exterior, providing you with a comfortable and beautiful sound experience with a metallic feel.
12V/1A Power Adapter
Equipped with a 12V/1A power adapter, with overheat protection/overvoltage protection and other protection features, you do not have to worry about the use of headphone amplifiers in the process of easy to produce safety hazards.
Ector
Reviewed in Italy on February 10, 2025
Funziona perfettamente, 4 canali separati
Peter
Reviewed in Sweden on January 24, 2025
Fungerar som förväntat
CJH NY
Reviewed in the United States on January 22, 2025
Works Great, when I connected two pair of headphones to my TV, you couldn’t hardly hear it. After adding this amplifier, you can adjust the volume individually so that you can hear and understand everything! Very pleased with this device.
Kapuchingi
Reviewed in Spain on January 19, 2025
Lo utilizo en la salida de auriculares de mi portátil pero cuando le ponias más de uno iba bajando la intensidad y casi no se oía. Esta maquina lo resuelve de una forma eficaz y con calidad de manera que cada uno ajusta con su potenciómetro el volumen que quiere. Aguanta hasta 4 auriculares metidos y no baja ni la calidad ni el volumen. Nosotros lo usamos para en verano ver pelis en la terraza en un oroyector enchufado al portatil sin molestar a nadie
Fred
Reviewed in the United States on August 20, 2024
I use this in my 57 Thunderbird to control the sound coming from a beutiful radio from classic auto that has poor audio. I use this in conjuction with fosi audio equilizer so I can keep the audio low on the low quality radio and amplify its signal before it goes to the amplifiers so the higher quality pre amping of the volume makes the sound in the car sound great. Without these fosi audio upgrades the beautiful but crappy sounding classic audio ratio blew my speakers with its extreme distortion. Now I control my volume from the Fosi upgrades, the item being reveiwed was use as a multi channel fadar / mixer.
Customer
Reviewed in the United States on July 8, 2023
Tested different wires, speakers, headphones, connectors, all distortion starts when the knobs reach about 75% of max. Anything higher and it starts to sound like those old commercials where the announcers voice sounds too loud for the mic. As for the actual volume, at 75% of max it is slightly less volume than when I directly connect speakers or headphones to the source. The splitter works just fine at least, plays one sound on 4 different outputs simultaneously just fine. I WAS writing this review with 2 stars, but then I realized...I never truly tested another audio source. I tested my laptops headphone jack, the monitors headphone jack (technically same source, just hdmi instead of 3.5mm jack), connected a 7.1 surround sound receiver and used it's headphone jack (main source still laptop though)...all gave same results. Towards end of review I realized all tests were technically on laptop and so I tested another, actual source, my PS5 (more specifically the headphone jack on controller). Works as intended. I directly connected to controller, then through amp/splitter while it was connected to controller. Knobs at max volume, clear audio still...and about double the volume of source. Very disappointed I'm not going to get to use this as I had intended, but the splitter function is still useful on laptop at least (I can connect my sub, speakers, and headset at once now). Also one thing to note...lots of electrical noise in headphones when amp is turned off (and plugged in) or when amp is plugged in and you're touching the amp and 3.5mm part of the headphone wire at the same time. Kinda cool if you think about it...you can "hear" the electricity going through you. Electrical noise is hardly there when plugged in amp/splitter and it's powered on (still audible if no audio, but not by much).
Chris
Reviewed in Canada on May 25, 2023
Bought this to hook up to my computer and play audio to my headphones and speakers from the USB DAC. This makes it super easy to just adjust volume on each independantly without worrying about blasting the volume after a switch or having to manually switch the 3.5mm cable on the DAC.It feels super well built, nice metal housing and volume knobs have a very sturdy feel when adjusting.Great value overall and well worth the purchase
Katie
Reviewed in the United States on September 18, 2022
After reading generally-favorable reviews of this item, it's attractive pricing prompted me to purchase one to try. The application in this case is TV-listening, not necessarily privacy, but as a means to better follow movie dialog, which has suffered from a lack of stress on diction within recent crops of actors, and of unwarranted dominance of music and effects tracks during mixdown in post-production. Moreover, the reverberant acoustics of our rather cavernous living room also sabotage speech intelligibility.This amp is packaged nicely; so well, in fact, that Amazon simply slapped their shipping label on the box it comes in. The amp is well protected in a custom-foam 'nest' along with its power adapter. The unit is small enough to nestle between couch cushions. Up to four watchers can share the TV audio, each with independent volume control... which is not only convenient, but necessary, as I found out.We tried the amplifier with multiple headphones, from very pricey studio-monitor types to 'stethoscope' headsets normally associated with dictating machines. The impedance and sensitivity differences between headphones makes the individual volume controls a must. Least sensitive were my go-to Sennheiser HD414s, a good choice for TV viewing from an intelligibility standpoint, although wearing them for more than an hour might be a problem. These were early 'open-air,' 'on-ear' types, now 40 years old. The most sensitive headphones were another Sennheiser 'over-the-ear,' studio-quality ones, which block nearly all outside noise, but are again not that comfortable for extended use.The surprise was the 'stethoscope' set, which pose no problem for wearing hours on end. The audio quality generally isn't that great with this type, but they do excel for speech intelligibility. A neat trick is to leave the normal TV speakers (or surround system) on, which will provide movie effects and music bass response while wearing this type of headset. Be sure to choose one that's "stereo" as many in this category are not (for dictating machines).Another tip: if your headphones have a built-in volume control, operate with that control wide-open and use the amplifier's volume control to set the sound level. That will maximize the headroom margin in the system.As for the performance of this little amp, again, it's excellent. I encountered absolutely no hum or noise attributable to the amp, action of the volume controls is smooth and wide-range, the amp generates no heat, and no problem with intermittent 3.5mm jack connections. By the way, if you are plagued with headphones or other gear that cuts-out as you wiggle those 3.5mm plugs, put a small drop of Caig DeoxIT Gold (sold on Amazon) on the plug. It keeps the connection solid for a long time, not like simply licking the plug... ugh.
Fil Vicente
Reviewed in Mexico on July 14, 2022
Como algo tan pequeño funciona muy bien. Superó todas mis expectativas
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