Description
Fosi Audio HT4S Multi-Channel Bluetooth Power Amplifier for Speakers & Subwoofers
Upgrade your audio setup with the Fosi Audio HT4S, a powerful multi-channel Bluetooth amplifier designed to enhance your listening experience. Whether you're setting up a home theater system, outdoor sound system, or a sim racing rig, this compact yet versatile amplifier delivers high-fidelity sound with deep bass and crystal-clear highs.
Key Features:
All-in-One High-Performance Amplifier
The HT4S is a stereo amplifier with an integrated DAC and power amplification, offering up to 5 speaker outputs. With 4.1 and 5.0 channel switchability, it provides flexible sound configurations for any audio environment. Featuring Bluetooth, AUX, and optical digital inputs, as well as pre-out connectivity, it ensures seamless compatibility with multiple devices.
Perfect for Multiple Audio Setups
Designed for indoor and outdoor applications, this amplifier is ideal for home theaters, cafes, restaurants, bars, and patios. Whether you want wall-mounted speakers, outdoor speakers, or an immersive desktop HiFi system, the HT4S adapts to your needs with ease.
Enhanced Home Theater & Sim Racing Experience
Take your racing simulation or home theater experience to the next level! The HT4S pairs seamlessly with bass shakers, delivering powerful sound output and bass boost that intensifies racing games and movies, making them feel more immersive than ever.
User-Friendly Controls & Elegant Design
Equipped with a built-in power supply, remote control, bass and treble adjustments, and a multifunctional central knob, the HT4S ensures effortless operation. The LED mode indicator light enhances its aesthetic appeal, while the all-metal CNC unibody construction guarantees durability and long-lasting performance.
Reliable and Durable Build
Continuing Fosi Audio's premium craftsmanship, the HT4S features a robust aluminum alloy body with a sandblasted finish, ensuring superior durability. Plus, enjoy peace of mind with Fosi Audio's 12-month warranty.
Technical Specifications:
-
Input Options: 3.5mm AUX, Optical, Bluetooth
-
Output Options: 3.5mm Pre-Out, Passive Speakers + Subwoofer
-
Rated Power Output:
-
4.1 Channel: 30W x 4 + 60W x 1 @ 4Ω
-
5.0 Channel: 30W x 5 @ 4Ω
-
-
Max Power Output: 50W x 5 @ 4Ω
Note: The HT4S is a stereo amplifier and does not support Dolby, DTS, or other multichannel surround sound formats.
Enhance your audio experience with the Fosi Audio HT4S—your ultimate amplifier for multi-speaker setups, home theaters, and immersive gaming!
Channel : Bluetooth 4.1 CH Amp
Input : Bluetooth + 3.5mm AUX + OPT
Output : 3.5mm Pre-Out + Speaker Out
SNR : ≥88dB
THD : ≤ 0.03%
Terminal Impedance : 4-8Ω
Rated Power Output : 30w*4+60W*1
MAX Power Output : 50Wx5 @4Ω
Work Voltage: AC 110V - 240V
Product Dimensions : 6.1 x 7.2 x 2 inches
In The Box
HT4S*1
Power Cord*1
Bluetooth Antenna*1
3.5mm Auxiliary Cable*1
Remote Control*1
HT4S User Manual*1
Warranty Period: 1 Year from the date of Invoice
Covered: Manufacturing Defects Only
Warranty Form: https://www.theaudiostore.in/pages/warranty-claim-form
Cable: 1-month warranty only for manufacturing defects only
Fosi Audio is a dynamic brand dedicated to providing the most comprehensive range of Hi-Fi audio products in the market. We cater to passionate audiophiles by offering Hi-Fi products, DIY kits, and expert guidance, ensuring an immersive audio experience. Beyond a mere transaction, we foster enduring relationships with our clients, supporting them throughout their audio journey.
Our diverse product lineup includes the Hi-Fi power amplifier, pre-amplifier, headphone amplifier, DAC, music player, Bluetooth receiver, DIY board, DIY chassis, and an array of DIY kits. These meticulously crafted offerings embody our commitment to exceptional sound quality and innovation.
Established in China in 2017, Fosi Audio was founded by a team of devoted audiophiles. Our products have gained significant popularity within the Chinese DIY audio community, amassing a large and dedicated following. To expand our reach beyond borders, we launched this website in 2017 and began offering a selection of products on Amazon under the name "Fosi audio." However, please note that many of our outstanding products are not yet available on this website or Amazon. If you cannot find what you're looking for, simply reach out to us via email, and we will be delighted to assist you in finding the perfect product to meet your needs.
At Fosi Audio, we are not just a brand; we are your partner in achieving audio excellence. Join us on this immersive sonic journey and experience the true essence of Hi-Fi audio.

Description
Fosi Audio HT4S Multi-Channel Bluetooth Power Amplifier for Speakers & Subwoofers
Upgrade your audio setup with the Fosi Audio HT4S, a powerful multi-channel Bluetooth amplifier designed to enhance your listening experience. Whether you're setting up a home theater system, outdoor sound system, or a sim racing rig, this compact yet versatile amplifier delivers high-fidelity sound with deep bass and crystal-clear highs.
Key Features:
All-in-One High-Performance Amplifier
The HT4S is a stereo amplifier with an integrated DAC and power amplification, offering up to 5 speaker outputs. With 4.1 and 5.0 channel switchability, it provides flexible sound configurations for any audio environment. Featuring Bluetooth, AUX, and optical digital inputs, as well as pre-out connectivity, it ensures seamless compatibility with multiple devices.
Perfect for Multiple Audio Setups
Designed for indoor and outdoor applications, this amplifier is ideal for home theaters, cafes, restaurants, bars, and patios. Whether you want wall-mounted speakers, outdoor speakers, or an immersive desktop HiFi system, the HT4S adapts to your needs with ease.
Enhanced Home Theater & Sim Racing Experience
Take your racing simulation or home theater experience to the next level! The HT4S pairs seamlessly with bass shakers, delivering powerful sound output and bass boost that intensifies racing games and movies, making them feel more immersive than ever.
User-Friendly Controls & Elegant Design
Equipped with a built-in power supply, remote control, bass and treble adjustments, and a multifunctional central knob, the HT4S ensures effortless operation. The LED mode indicator light enhances its aesthetic appeal, while the all-metal CNC unibody construction guarantees durability and long-lasting performance.
Reliable and Durable Build
Continuing Fosi Audio's premium craftsmanship, the HT4S features a robust aluminum alloy body with a sandblasted finish, ensuring superior durability. Plus, enjoy peace of mind with Fosi Audio's 12-month warranty.
Technical Specifications:
-
Input Options: 3.5mm AUX, Optical, Bluetooth
-
Output Options: 3.5mm Pre-Out, Passive Speakers + Subwoofer
-
Rated Power Output:
-
4.1 Channel: 30W x 4 + 60W x 1 @ 4Ω
-
5.0 Channel: 30W x 5 @ 4Ω
-
-
Max Power Output: 50W x 5 @ 4Ω
Note: The HT4S is a stereo amplifier and does not support Dolby, DTS, or other multichannel surround sound formats.
Enhance your audio experience with the Fosi Audio HT4S—your ultimate amplifier for multi-speaker setups, home theaters, and immersive gaming!
Channel : Bluetooth 4.1 CH Amp
Input : Bluetooth + 3.5mm AUX + OPT
Output : 3.5mm Pre-Out + Speaker Out
SNR : ≥88dB
THD : ≤ 0.03%
Terminal Impedance : 4-8Ω
Rated Power Output : 30w*4+60W*1
MAX Power Output : 50Wx5 @4Ω
Work Voltage: AC 110V - 240V
Product Dimensions : 6.1 x 7.2 x 2 inches
In The Box
HT4S*1
Power Cord*1
Bluetooth Antenna*1
3.5mm Auxiliary Cable*1
Remote Control*1
HT4S User Manual*1
Warranty Period: 1 Year from the date of Invoice
Covered: Manufacturing Defects Only
Warranty Form: https://www.theaudiostore.in/pages/warranty-claim-form
Cable: 1-month warranty only for manufacturing defects only
Fosi Audio is a dynamic brand dedicated to providing the most comprehensive range of Hi-Fi audio products in the market. We cater to passionate audiophiles by offering Hi-Fi products, DIY kits, and expert guidance, ensuring an immersive audio experience. Beyond a mere transaction, we foster enduring relationships with our clients, supporting them throughout their audio journey.
Our diverse product lineup includes the Hi-Fi power amplifier, pre-amplifier, headphone amplifier, DAC, music player, Bluetooth receiver, DIY board, DIY chassis, and an array of DIY kits. These meticulously crafted offerings embody our commitment to exceptional sound quality and innovation.
Established in China in 2017, Fosi Audio was founded by a team of devoted audiophiles. Our products have gained significant popularity within the Chinese DIY audio community, amassing a large and dedicated following. To expand our reach beyond borders, we launched this website in 2017 and began offering a selection of products on Amazon under the name "Fosi audio." However, please note that many of our outstanding products are not yet available on this website or Amazon. If you cannot find what you're looking for, simply reach out to us via email, and we will be delighted to assist you in finding the perfect product to meet your needs.
At Fosi Audio, we are not just a brand; we are your partner in achieving audio excellence. Join us on this immersive sonic journey and experience the true essence of Hi-Fi audio.
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from 4877 reviewsKZ Castor Harman Target Version – Review
Design & Comfort
Lightweight, durable, and comfortable with a detachable cable. The in-line mic is useful for calls and gaming.
Sound Quality
Bass: Punchy and deep without overpowering.
Mids: Clear vocals and instruments.
Highs: Crisp but slightly bright.
Soundstage: Decent separation for immersive listening.
Pros:
✔ Enhanced bass
✔ Balanced tuning
✔ Comfortable & durable
✔ Affordable
Verdict:
A budget-friendly IEM with great sound and comfort, though the mic is just decent.
I'm using first time DAC most of the people refer this varient, difference between 3.5mm jac and this DAC D07 is absolutely awesome, so much details in hearing a song and music, loved it ❤️❤️❤️❤️👌👌👌🙏🙏🙏
Solid pouch
With good space
The product is worth the money
And I personally love the your faster delivery service
I got the product just in with 30 Hrs

I like Moondrop ECHO-A Dac. It is not powerful Dac but it produces quality sound .

Great for listening to all music genres, gaming on PC or consoles or pretty much any thing you'd like to do with a pair of earphones.
Superb packaging 👍🏻 delivered what was promised.

I recently got my hands on the ROSESELSA AURORA Ultra IEM, and I must say, it has exceeded my expectations! For under 2,000 INR, this IEM delivers exceptional value and performance that can easily compete with many pricier models out there.
What really stands out to me is its versatility. The AURORA shines across all genres, whether I'm diving into classical symphonies, jamming to rock anthems, or vibing with electronic beats. The sound quality is simply fantastic, making every listening session a joy.
A cherry on top is the comfort factor—these IEMs are small and lightweight, so they don’t cause any discomfort during long listening sessions. If you’ve had issues with larger IEM shells in the past, you’ll find the AURORA to be a perfect fit. Plus, the cable quality is impressive for the price, adding to the overall value of this product.
To unlock the full potential of these IEMs, I highly recommend investing in an external dongle. I personally use the Kiwi Ear Allegro Mini DAC, and it has truly elevated my audio experience. If you're on the hunt for a budget-friendly IEM that doesn’t compromise on sound quality, the ROSESELSA AURORA is a must-try!
I also want to take a moment to thank the audio store for their outstanding service. My order arrived in perfect condition, and their customer support team was incredibly friendly and helpful. Overall, this has been a wonderful experience, and I’m absolutely thrilled with my purchase!
As a v16 owner this is a worthy upgrade .
Fit :
The iem is designed aesthetically that it fits like custom made
Sound impressions :
Treble is perfectly done with being sibilant, Mids sounds very organic and clear, Bass is the best part here it's a step up from their previous flagship v16.
Staging is better and so is the resolution, A total flagship level iem which punches above the price tag
Thanks to Pritam for his exceptional customer service and deal .
Definitely recommended

Have a great features and I am very happy after buying this m71 thanks audio store 🙏🙏

Time Spent with this DAP is more than 50 days, used many IEMs from Budget range to high end.
OBSERVATION & EXPERIENCE SO FAR.
- Wide soundstage, it's creating a spacious listening experience.
- Smooth and refined sound, with good bass & trebles. I liked it.
- little high Volume doesn't hurt ears because of spaciousness which this DAP creates.
- Main unique point is Vocals & Instruments separation, it's best.
- So far, I noticed Battery back up is really good. Will check it over time and provide feedback.
- Does not get warm that too after using for hours.
- Best software & Shanling Music app, it's very fast ( I use 1TB fully loaded Micro SD card.)
Please Note - Little more care is needed while handling as it has Glass tubes. Again it's unique offering & tubes makes music more enjoyable.
CONS-
1. Charging time ( it will get solve by software updates in future, Brand has co
nfirmed it in their post)
2. Only one colour option is available from Brand.
3. Some settings currently not present, Brand may add in future updates ( DSD gain Compensation, PEQ, MSEB, Night light short cut in quick pannel)
CONCLUSION-
a. Highly recommend those who want detailed & immersive experience.
b. THREE IN ONE- One DAP but three modes, all three sounds differently. One mode Transistor (without Tubes) and two Tube modes (Triode & Ultra- linear).

Sterdy & beautiful cable. I am using it with Hidiz MP145 Planner Magnetic IEM. It add details to music over stock cable. Makes all aspect of sound quality better.

I am writing review after One month regularly uses with my two DAP - Shanling M8t, Hiby R4.
POSITIVES-
1. Best Soundstage
2. Balanced sound
3. Musical & Makes music more enjoyable to ears.
4. No fatigue despite of metal construct.
5. Weight distribution is really good.
6. Largest Magnetic planner in the Category.
7. Details & instruments separation at best.
CONS-
1. Small ears may face challenge. Plz contact team ATS before purchase. Normal ear size, No issues with fit & long usage.
2. Stock cable is good but doesn't suit this IEM.
I am using this with Divinus Auram cable, which goes really well with this by appearance as well as by performance.
CONCLUSION-
1. Very very happy with the purchase. It's my main IEM in daily music journey.
2. My suggestion is Music enthusiast must have atleast one 'Planner Magnetic IEM', believe me I found that the the songs which I am listening since decades are sounding differently with some more details with this IEM.

The KZ Castor is an excellent choice for budget audiophiles. It delivers superb sound quality that rivals much more expensive headphones, with clear highs, rich mids, and deep bass. The build quality is solid, offering both durability and comfort for long listening sessions. At its price, it’s a fantastic value, outperforming many premium options. Highly recommended!

i think it's a great choice for someone who's just starting with the "iem" audiophile thing and it sounds good pretty good for the price range, it's sound clear and crisp, the bass is a little on the lower side but nonetheless great product if you are just starting, oh and yes the delivery was fast got it in a day.