Meet the All-New ZP3 Preamp

Fosi Audio P4 Mini Preamp with 3 RCA Inputs, EQ/Bypass, Treble & Bass Tone Control with Remote Control - Fosi Audio
Fosi Audio P4 Mini Preamp with 3 RCA Inputs, EQ/Bypass, Treble & Bass Tone Control - Fosi Audio
Fosi Audio P4 Mini Preamp with 3 RCA Inputs, EQ/Bypass, Treble & Bass Tone Control - Fosi Audio
Fosi Audio P4 Mini Preamp with 3 RCA Inputs, EQ/Bypass, Treble & Bass Tone Control - Fosi Audio
Fosi Audio P4 Mini Preamp with 3 RCA Inputs, EQ/Bypass, Treble & Bass Tone Control - Fosi Audio
Fosi Audio P4 Mini Preamp with 3 RCA Inputs, EQ/Bypass, Treble & Bass Tone Control - Fosi Audio
Fosi Audio P4 Mini Preamp with 3 RCA Inputs, EQ/Bypass, Treble & Bass Tone Control - Fosi Audio
Fosi Audio P4 Mini Preamp with 3 RCA Inputs, EQ/Bypass, Treble & Bass Tone Control - Fosi Audio

Product Highlights

3

RCA Inputs

≥ 110dB

SNR

≤ 0.003%

THD+N

≥105dB

SINAD

Product Highlights

3

RCA Inputs

≥ 110dB

SNR

≤ 0.003%

THD+N

≥105dB

SINAD

Fosi Audio P4 Mini Preamplifer

$99.99

Features
  • Triple RCA Inputs
  • Bass, Treble, and Gain Control
  • Motorized Pot for Smooth Adjustment
  • Bypass Function for Pure Signal Path
  • Op-Amp Rolling: SS3602, MUSES02, OPA2134PA
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Review Videos

Finally! What We’ve All Needed! Won’t Stay in Stock…

cheapaudioman

P4 is a home‑run preamp, combining quality and utility.

Old Guy Hifi

Practical review: P4 integrates neatly into entry‑level Hi‑Fi.

Matt Coykendall

Deep dive: P4 + V3 Mono synergy explained.

Pieces of Vinyl

Comparative test: do you really need the P4 preamp?

Mad Audio

Is P4 the best budget analog preamp available?

Techder Audios

Finally! What We’ve All Needed! Won’t Stay in Stock…

cheapaudioman

P4 is a home‑run preamp, combining quality and utility.

Old Guy Hifi

Practical review: P4 integrates neatly into entry‑level Hi‑Fi.

Matt Coykendall

Deep dive: P4 + V3 Mono synergy explained.

Pieces of Vinyl

Comparative test: do you really need the P4 preamp?

Mad Audio

Is P4 the best budget analog preamp available?

Techder Audios
Load video:

Another Masterpiece Driven by Voice of Customers

The P4 is a mini preamp self-developed by Fosi Audio based on extensive feedback from users worldwide after the launch of the V3 stereo amp.

  • Input: RCA x3; Output: RCA, Pre-Out
  • SNR≥ 110dB; THD+N≤ 0.003%
  • Frequency Response: 20Hz-20kHz(±0.1dB)

Product details

Description
  • Mini Control Hub: The P4 supports up to 3 RCA inputs, allowing easy connection to CD players, streamers, DACs, cassette decks, and turntables with built-in phono preamp. Switch between sources with a click for seamless audio control.

  • Practical and User-Friendly: Equipped with volume control, bass and treble adjustment with bypass function, three-level gain control, and a remote. The preamplifier offers convenient audio setup and optimization, making every listening session effortless.

  • Motorized Potentiometer: Featuring a high-precision motorized analog pot, the P4 delivers smooth volume adjustment, reduced noise, and minimal distortion for a purer and more refined sound experience.

  • Compact and Solid: The P4 stereo preamp features a sleek, minimalist design that saves space and provides robust resistance to electromagnetic interference, ensuring reliable performance over time.

  • Exceptional Performance: With a low noise floor, high signal-to-noise ratio, and extremely low distortion, the P4 pre-amplifier delivers pristine audio, ensuring accurate sound reproduction and enhancing the listening experience for audiophiles
Specifications

Channel: 2.0
Input Mode: RCA*3
Output Mode: RCA, Pre-out
SNR: ≥ 110dB
Dynamic Range: ≥ 110dB
THD+N: ≤ 0.003%
Crosstalk: ≥ 105dB
Noise Floor: ≤ 9μV
Tone Adjustment Gain: ±12dB
Frequency Response: 20Hz-20kHz(±0.1dB)
Power Supply: DC 12V/1.5A

What‘s in the box？
  • Fosi Audio P4 Mini Preamplifier x 1
  • 12V/1.5A Power Supply x 1
  • User’s Manual x 1

Which Product is right for you?

Compare products to find the best one for your needs.

From $199.99

Fosi Audio ZP3 Preamplifer

Learn more
Type
Preamp
Input
RCA x2, XLR
Output
RCA, XLR, Sub-Out
Bass & Treble Control
Yes
THD+N
≤ 0.0007%
SNR
≥ 115 dB
From $99.99

Fosi Audio P4 Mini Preamplifer

Learn more
Type
Preamp
Input
RCA x3
Output
RCA, Pre-Out
Bass & Treble Control
Yes
THD+N
≤ 0.003%
SNR
≥110dB
From $79.99

Fosi Audio P3 Tube Preamplifier

Learn more
Type
Preamp+Headphone Amp
Input
Bluetooth, RCA
Output
RCA, 3.5mm Headphone Jack, AUX
Bass & Treble Control
Yes
THD+N
≤0.02%
SNR
≥103dB
From $199.99

Fosi Audio ZP3 Preamplifer

Learn more
Type
Preamp
Input
RCA x2, XLR
Output
RCA, XLR, Sub-Out
Bass & Treble Control
Yes
THD+N
≤ 0.0007%
SNR
≥ 115 dB
From $99.99

Fosi Audio P4 Mini Preamplifer

Learn more
Type
Preamp
Input
RCA x3
Output
RCA, Pre-Out
Bass & Treble Control
Yes
THD+N
≤ 0.003%
SNR
≥110dB
From $79.99

Fosi Audio P3 Tube Preamplifier

Learn more
Type
Preamp+Headphone Amp
Input
Bluetooth, RCA
Output
RCA, 3.5mm Headphone Jack, AUX
Bass & Treble Control
Yes
THD+N
≤0.02%
SNR
≥103dB

FAQs

Please read our FAQs page to find out more.

How do I integrate P4 into a audio system?

First, connect P4 to your audio sources via RCA cables, then connect P4 to an amplifier via RCA cables, and lastly, use speaker cables to connect the amplifier to the passive speakers.

What is the function of the Bypass switch?

This is the bypass function for turning the tone control on and off. Sliding it up bypasses the bass and treble adjustments while sliding it down enables the bass and treble controls. The bypass switch won’t function on the volume control.

What are the benefits of the high-precision motorized analog potentiometer in the P4?

It ensures smooth, precise volume control, and enhances usability while reducing noise and distortion. When adjusting the volume with the remote, the potentiometer‘s motor syncs with the physical knob, providing a seamless and intuitive experience.

What can the pre-out port used for?

Allows for easy connection to external powered subwoofers or additional amplification. It ensures seamless integration with your audio system, enabling enhanced bass response or driving additional speakers for a more immersive listening experience.

Customer Reviews

Based on 67 reviews
91%
(61)
7%
(5)
1%
(1)
0%
(0)
0%
(0)
91.0
92.4
G
Gombocz A.
Great little device.

I love this little preamp from Fosi. I use it as a desktop device, next to an Xduoo tube headphone amp, an SMSL DAC, and AIYIMA A07 Max power amp. I like the design, and the simplicity of use, it is easy to replace the op-amp in it, but... Those buttons are hard to take off...

User picture
L
Leonard Downing
Perfect Specs - Perfection function

Simple, functional, ultra clean specs, quality build, just right connectivity, and pairs well with nicely matched Fosi Audio power amps. Mighty performance that stands equal next to larger, much more expensive pre amps. Large performance that does not dominate the wife approved decor of a room.

F
FFW
small form, big value

Exactly what i could wish for in a small
Factor: versitale and nice design.

M
Michael Glöckner
small but powerfull

great for people, that need a small footprint preamp. really good sound, enough inputs, remote control

S
S.G. Pels
Small objects of desire

After watching countless reviews I felt like I was back in the seventies again, when I had to assemble my first basic stereo set from different components like a sony 212 amp, philips ah489 speakers and an akai turntable. It didn’t only look great, it had a great sound too, at least to me. I truly felt like a junior audiophile.

Fast forward to today and again I had the same fun experience, even though the components were all of the same brand, I still had a lot of flexibility, In my case I went for V3 mono’s, because I was actually contemplating buying full fledged units, but Fosi gave me the opportunity to try out such a system (2xv3 mono, zd3 dac and a p4 preamp) without braking the bank.

Not only does it all look and feel absolutely great, it also sounds very good, and I haven’t even tried rolling op amps yet. I also recently bought a fosi phono tube preamp for a vintage technics sl2000, which absolutely enhanced the sound audible and exponentially, and that for a ridiculously low price of €50,- (special offer). It actually made me wonder how they still make a profit.

No regrets here!

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