Fosi Audio P4 Amplifier Review
Our verdict
The Fosi Audio P4 earns one of the highest buyer ratings in this category at 4.7 stars from 237 reviews, setting it apart from cheaper phono preamp alternatives at the $99.99 price point. For vinyl listeners who want a meaningful step up from budget phono stages, this is a credible choice.
Check price on AmazonBest for
Turntable enthusiasts upgrading from a basic built-in or entry phono stage who want a noticeable improvement in sound quality without crossing into audiophile-tier pricing
Skip if
You already have a quality phono stage in your receiver or a dedicated high-end outboard preamp, as the P4 targets the upgrade market, not the entry-level one
- Dimensions 5.5 X 4 X 1.2 In
- Weight 477.0 lb
- Priced 16% above the category median ($86.27 across 57 tracked models)
- Weight of 477.0 lb - heavier than 94% of the 57 models we track
Pros
- 4.7-star average from 237 reviews is one of the top scores in this product category
- Compact 5.5 x 4 x 1.2 in footprint fits anywhere in a turntable setup
- Fosi Audio is an established brand with a track record in budget-to-mid audio gear
- At $99.99 it sits at a meaningful upgrade tier over $20 to $40 phono preamps
Cons
- No published gain spec or MM/MC compatibility details in available product data
- 237 reviews, while positive, is a moderate sample size for firm conclusions
- At $99.99 it is not a budget buy, and buyers who want a basic phono stage can do it for far less
Our scorecard
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Owner rating4.7/5
4.7 average across 237 owner ratings
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Popularity2.3/5
237 owner reviews, fewer than most models here
The overall score is owner satisfaction weighted by how many reviews back it, so a high rating from few reviews counts for less. The bars below show where this model stands against the other AV receivers and amplifiers, soundbars, home theater speakers, subwoofers, surround sound systems and Blu-ray players we track in this category on price, popularity and size. Context, not marks against it, and our read of the data, not a lab test.
Overview
['Fosi Audio has built a strong reputation in the budget-to-midrange amplifier and preamp space, and the P4 represents the brand at its phono-stage best. At $99.99 it competes in a tier where sonic differences become meaningful, and the 4.7-star average from 237 buyers backs that up with real-world validation.', 'Physical dimensions of 5.5 x 4 x 1.2 in make it a slim, unobtrusive unit that sits neatly beside a turntable or under a rack shelf. The compact chassis belies what the buyer scores suggest: a phono stage that performs above its price in the opinions of those who own it.', 'No published power output or gain figure is available in product data, which is typical for phono preamps where the signal gain is fixed by RIAA equalization curve standards. Buyers should verify MM or MC cartridge compatibility with the current listing before purchasing.']
Specifications
| Dimensions | 5.5 X 4 X 1.2 In |
|---|---|
| Weight | 477.0 lb |
Performance notes
Physical dimensions are 5.5 x 4 x 1.2 in. No power output, gain, or signal-to-noise ratio figures are available in confirmed product data. The unit is classified as an amplifier in the preamp category. Weight data in the listing appears as a data anomaly and is not cited here.
What buyers say
A 4.7-star rating from 237 reviews is a strong and consistent signal of buyer satisfaction. At the $100 phono preamp tier, buyers tend to be more discerning than ultra-budget shoppers, making this score especially meaningful. It suggests the P4 delivers on sound quality expectations for its price.
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Frequently asked questions
What is the difference between a phono preamp and a regular preamp?
A phono preamp does two things a standard line-level preamp does not. First, it amplifies the very low-level signal from a turntable cartridge to line level. Second, it applies RIAA equalization, a standardized curve that reverses the frequency shaping applied to vinyl during the cutting process. Without both steps, records sound thin, quiet, and imbalanced. A regular preamp only handles line-level signal and cannot substitute for a phono stage.
Can the Fosi Audio P4 work with a moving coil cartridge?
Buyers should check the current product listing and manufacturer specifications to confirm MC cartridge support. MC cartridges output a much lower signal than MM cartridges and require significantly higher gain, typically 60 dB or more. Many phono preamps in this price range support MM only or include a switchable MM/MC mode. Confirm before purchasing if you use an MC cartridge.
Where does the P4 fit in a home audio chain?
Connect your turntable's RCA output to the P4 input, then run the P4 output to any line-level input on your integrated amplifier or receiver, such as AUX or CD. If your receiver already has a phono input, bypass the P4 entirely and use the built-in stage instead. The P4 adds value when your amplifier lacks a phono input or when you want to replace a poor-quality built-in phono stage with something better.