---
product_id: 97319622
title: "BOX X4"
brand: "fosi audio"
price: "₨63791"
currency: LKR
in_stock: null
reviews_count: 9
category: "Fosi Audio"
url: https://www.desertcart.lk/products/97319622-box-x4
store_origin: LK
region: Sri Lanka
---

# Dual JAN 5725W vacuum tubes for warm sound Low-noise MM phono to line-level conversion 3-band Volume/Bass/Treble control BOX X4

**Brand:** fosi audio
**Price:** ₨63791
**Availability:** ❌ Out of Stock

## Summary

> 🎶 Elevate your vinyl vibe with tube-powered clarity and customizable control!

## Quick Answers

- **What is this?** BOX X4 by fosi audio
- **How much does it cost?** ₨63791 with free shipping
- **Is it available?** Currently out of stock
- **Where can I buy it?** [www.desertcart.lk](https://www.desertcart.lk/products/97319622-box-x4)

## Best For

- fosi audio enthusiasts

## Why This Product

- Trusted fosi audio brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Tube-Driven Warmth:** Dual JAN 5725W vacuum tubes deliver rich, immersive analog warmth that elevates every record.
- • **Noise-Free Listening:** Advanced low-noise circuitry and grounding post eliminate hum and interference for crystal-clear playback.
- • **Tailor Your Soundstage:** Precision volume, bass, and treble controls let you sculpt your vinyl experience to perfection.
- • **Versatile Connectivity:** Supports MM turntables plus 3.5mm AUX input and headphone output for seamless multi-use setups.
- • **Built to Last & Impress:** Solid metal chassis with glowing tube LEDs combines durability with eye-catching vintage flair.

## Overview

The Fosi Audio Box X4 is a compact, freestanding phono preamp designed for MM turntables, featuring dual JAN 5725W vacuum tubes that provide warm, detailed analog sound. It includes volume, bass, and treble controls for personalized audio tuning, supports 3.5mm AUX input and headphone output, and incorporates low-noise circuitry with a grounding post to ensure clean signal conversion. Its robust metal build and glowing tube LEDs make it both a durable and stylish addition to any audiophile’s setup.

## Description

Buy Fosi Audio Box X4 Phono Preamp with JAN 5725W Vacuum Tubes for MM Turntable Phonograph Record Player with Volume Bass Treble Control: Phono Preamps - desertcart.com ✓ FREE DELIVERY possible on eligible purchases

Review: It's terrific - I needed a preamp because I couldn't do what I wanted with my existing setup. I had Fluance RT-85 turntable > Onkyo TX-SV575 (25 years old) > Rockville 21-band graphic EQ via Tape 2 monitor > Wharfdale Diamond 7.2 bookshelf speakers (also 25 years old). This setup sounded great, but I also want to have the music play in other rooms in perfect synchronization. I use the Wiim streaming device for this. The issue is that with that is that the sounds lagged a noticeable few milliseconds in the other rooms. The Wiim synch feature didn't work because the source setup didn't have the signal come from the Wiim. I need to change the order of the signal chain so that the turntable signal passed through the Wiim then to the receiver. And that's why I needed a pre-amp. After a night of researching solid state and tube preamps, I decided on the Fosi Box X4. I ordered it after 3am and it arrived before 6pm that same day (nice job, desertcart!). Set up was easy. The only odd thing was that the grounding post on the X4 is spring-loaded mechanism that seems intended for bare wire or a pin rather than the spade connector that is common on turntables. So I fed one prong of th fork into the opening and that works fine. The chain is now turntable > preamp > EQ > Wiim > receiver. This works but the sound seemed a little off. especially on older records. If I spent more time adjusting the EQ, I could probably get the sound to where I want it, but I'm lazy. Then it hit me, the sound out of the preamp to the receiver should be very good, so I set the EQ to direct mode which bypasses the adjustments of the EQ. I had to up the gain on the preamp after this since the EQ was boosting the level. Voila! That did it. Everyone is right that the X4 presents a wide and immersive soundstage. All the different pieces of percussion, acoustic and electric bass, piano, guitars, and vocals are all smooth and clear. I may keep this as the regular set up bypassing the EQ, and just using the EQ on tape and CD. This is my first tube set up, so I don't think I'll be making and tube changes for now. Definitely a great product, great performance, at a great price. I recommend it.
Review: Fantastic Phono Preamp with Headphone Output Too! - It's a unique combination of tube phono preamp, component preamp + headphone amp and for the price it's ridiculously good value. My current amp has no headphone jack and with the X4, I now have the option to listen to vinyl with my headphones. It has plenty of power to drive my headphones to extremely loud levels. This preamp has bass and treble controls that allow me to adjust the sound heard through the headphones as well as the speakers - I never seen this feature on a phono preamp and love it. It came with 2 GE 5654W tubes. They are a very nice tubes and actually cost about $15 each, so that’s $30 of the value right there. One of the tubes had a slight bend in the pin that I had to bend straight to get it to fit in the preamp socket (typical problem with tubes…they are delicate). It has red LEDs that light up the tubes that make it look cool. The unit itself is built like a tank (solid metal casing). Attaching my record player to the preamp was simple and the sound quality is amazing! The sound using these tubes is rich and detailed and being able to adjust the bass and treble really lets me dial in the sound for different speakers. If you plug an aux cord into the unit, the phono preamp turns off and defaults to the aux input (gotta pull out aux and then the phono preamp comes back on). Overall I’m amazed at how good of a phono preamp this is for the money. The headphone and aux input preamp are just icing on the cake. Love this X4 phono preamp!!!

## Features

- Upgrade your home audio system with the new-generation phono preamp, the Fosi Audio BOX X2 upgraded version
- 5725W Tube MM Phono Preamplifier: The BOX X4 phono preamp supports 3.5MM AUX and MM turntable input, converting phono signals to Line Level with low-frequency noise removal using high-quality components and low-noise integrated circuits. Protect your turntable with the grounding post feature
- Tube Headphone Amplifier & Preamplifier: The Fosi Audio BOX X4's versatile design includes a 3.5MM AUX headphone and RCA output, offering a range of usability beyond expectations
- Applicable Vacuum Tube Model: 6K4/6J1/6J4/GE5654/6AK5/66*In vacuum tubes, etc. Achieve a customized stereo system by replacing vacuum tubes. With different tubes producing unique sounds, it's a DIY opportunity worth exploring
- What You Get: BOX X4 phono preamp, DC 12V power supply, user manual, 5725W Tube*2

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B07L4TMHRN |
| Best Sellers Rank | #57,271 in Electronics ( See Top 100 in Electronics ) #8 in Home Audio Phono Preamps |
| Brand | Fosi Audio |
| Date First Available | December 5, 2018 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 12.8 ounces |
| Item dimensions L x W x H | 4 x 2 x 1 inches |
| Item model number | BOX X4 |
| Manufacturer | Fosi Audio |
| Material | Glass, Metal |
| Maximum Supply Voltage | 12 Volts (DC) |
| Minimum Supply Voltage | 12 Volts (DC) |
| Mounting Type | Freestanding |
| Number of Channels | 3 |
| Package Type Name | case |
| Product Dimensions | 4 x 2 x 1 inches |
| Voltage | 12 Volts (DC) |

## Product Details

- **Item dimensions L x W x H:** 4 x 2 x 1 inches
- **Manufacturer:** Fosi Audio
- **Maximum Supply Voltage:** 12 Volts (DC)
- **Minimum Supply Voltage:** 12 Volts (DC)
- **Voltage:** 12 Volts (DC)

## Images

![BOX X4 - Image 1](https://m.media-amazon.com/images/I/61W0YonYLBL.jpg)

## Questions & Answers

**Q: I have the pyle turntable and fosi audio tb10a amp but the sound is very low, so i need to add this phono preamp to amplify sound?**
A: Yes, you need connect this phono preamp between the turntable and tb10a amp, it will amplify the sound also improve the sound quality.
Thanks.

**Q: Can I directly connect this phono preamp to the speakers?**
A: If your speakers are powered speakers, you can directly connect this preamp to the speakers. 
But you need add an amplifier or receiver to the passive speakers.
Thanks.

**Q: Does this work best with Ceramic or Magnetic stylii? Can it do both?**
A: As long as your cartridge can output a voltage between ~2.0 -5 0 millivolts, the Fosi Audio Box X4 should work.  Amazon cells ceramic cartridges around $10, that I want to experiment with one.  Thanks for your question.

**Q: Why would an upgraded model have an snr of 70db and the older version is at 98db? seems like a downgrade. are those specs correct?**
A: I have a feeling that either this measurement is incorrect or the previous model's measurement is wrong. There is not enough information in either measurement; how did they do it? What kind of signal was used? What frequency? Was this measured with or without a signal going into it? Was it measured while playing an actual track off vinyl, or dead wax? Did the SNR change if you engaged the EQ? 

Even if the previous model gave you 98dB, it's impossible to reach that measurement with vinyl — even the cleanest, best vinyl ever made while using the most expensive, best stylus, cartridge, preamp, etc. isn't going to give you anything better than ~70dB. The X4 specs state ≥ 70dB which means at the very least it will give you 70dB or above. 

Having said all that, I think the X4 sounds great, especially for the price!

## Customer Reviews

### ⭐⭐⭐⭐⭐ It's terrific
*by B***F on July 27, 2023*

I needed a preamp because I couldn't do what I wanted with my existing setup. I had Fluance RT-85 turntable > Onkyo TX-SV575 (25 years old) > Rockville 21-band graphic EQ via Tape 2 monitor > Wharfdale Diamond 7.2 bookshelf speakers (also 25 years old). This setup sounded great, but I also want to have the music play in other rooms in perfect synchronization. I use the Wiim streaming device for this. The issue is that with that is that the sounds lagged a noticeable few milliseconds in the other rooms. The Wiim synch feature didn't work because the source setup didn't have the signal come from the Wiim. I need to change the order of the signal chain so that the turntable signal passed through the Wiim then to the receiver. And that's why I needed a pre-amp. After a night of researching solid state and tube preamps, I decided on the Fosi Box X4. I ordered it after 3am and it arrived before 6pm that same day (nice job, Amazon!). Set up was easy. The only odd thing was that the grounding post on the X4 is spring-loaded mechanism that seems intended for bare wire or a pin rather than the spade connector that is common on turntables. So I fed one prong of th fork into the opening and that works fine. The chain is now turntable > preamp > EQ > Wiim > receiver. This works but the sound seemed a little off. especially on older records. If I spent more time adjusting the EQ, I could probably get the sound to where I want it, but I'm lazy. Then it hit me, the sound out of the preamp to the receiver should be very good, so I set the EQ to direct mode which bypasses the adjustments of the EQ. I had to up the gain on the preamp after this since the EQ was boosting the level. Voila! That did it. Everyone is right that the X4 presents a wide and immersive soundstage. All the different pieces of percussion, acoustic and electric bass, piano, guitars, and vocals are all smooth and clear. I may keep this as the regular set up bypassing the EQ, and just using the EQ on tape and CD. This is my first tube set up, so I don't think I'll be making and tube changes for now. Definitely a great product, great performance, at a great price. I recommend it.

### ⭐⭐⭐⭐⭐ Fantastic Phono Preamp with Headphone Output Too!
*by R***K on May 20, 2023*

It's a unique combination of tube phono preamp, component preamp + headphone amp and for the price it's ridiculously good value. My current amp has no headphone jack and with the X4, I now have the option to listen to vinyl with my headphones. It has plenty of power to drive my headphones to extremely loud levels. This preamp has bass and treble controls that allow me to adjust the sound heard through the headphones as well as the speakers - I never seen this feature on a phono preamp and love it. It came with 2 GE 5654W tubes. They are a very nice tubes and actually cost about $15 each, so that’s $30 of the value right there. One of the tubes had a slight bend in the pin that I had to bend straight to get it to fit in the preamp socket (typical problem with tubes…they are delicate). It has red LEDs that light up the tubes that make it look cool. The unit itself is built like a tank (solid metal casing). Attaching my record player to the preamp was simple and the sound quality is amazing! The sound using these tubes is rich and detailed and being able to adjust the bass and treble really lets me dial in the sound for different speakers. If you plug an aux cord into the unit, the phono preamp turns off and defaults to the aux input (gotta pull out aux and then the phono preamp comes back on). Overall I’m amazed at how good of a phono preamp this is for the money. The headphone and aux input preamp are just icing on the cake. Love this X4 phono preamp!!!

### ⭐⭐⭐⭐ Phono preamp is excellent, headphone amp isn't
*by S***K on November 12, 2024*

The phono preamp sounds surprisingly great with every cartridge I throw at it. Plenty of detail, punch, warmth but not dull at all, with a nice quiet background, too. The tone controls are legitimately useful, with logically-chosen frequencies for a change. The X4 is worth the price for the phono preamp alone, imo. But the headphone output sounds boxy. It's tinny, lacking low end AND high end. It might come in handy if you need a basic monitoring function but that's about it. One other thing I don't like; the cheesy lights that make the tubes glow unnaturally. Totally unnecessary. They could have taken the money they spent trying to make this preamp more appealing to gamers and spent it on better circuitry for the headphone out. Overall I'd give the Box X4 2.5 overall stars because of the headphone output and fake lights. However, the phono preamp itself sounds SO GOOD that I have to up it to 4 stars. This preamp easily outperforms the phono preamps in my Denon receiver, my Denon mixer, and my Pioneer 250MKII mixer. If you buy it for that and not for the headphone amp I think you'll be pleasantly surprised if not shocked!

## Frequently Bought Together

- Fosi Audio Box X4 Phono Preamp with JAN 5725W Vacuum Tubes for MM Turntable Phonograph Record Player with Volume Bass Treble Control
- Monoprice 1.5ft Premium 2 RCA Plug/2 RCA Plug M/M 22AWG Cable - Black
- Riverstone Audio - Tested/Matched Pair (2 Tubes) 7-Pin JAN 5654W Fully-Tested Vacuum Tubes - Upgrade for 6AK5 / 6J1 / 6J1P / EF95 - JAN 5654W Platinum Grade Pair

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*Product available on Desertcart Sri Lanka*
*Store origin: LK*
*Last updated: 2026-03-12*