FOSI Audio Amplifiers Compared 2026: Which of 8 Amps Fits Your Speakers?
You finally pulled the old bookshelf speakers out of the garage, wiped the dust off the cones and lined them up on either side of the TV. Then you went shopping for something to power them and hit a wall of nearly identical metal boxes: V3, TB10D, BT20A Pro, BT20A MAX, ZA3, V3 Mono. Same orange knob, same chip name in the listing, prices from $69.99 to $279.99.
They look alike, but they're built for different jobs. Olivia Reviews lined up FOSI Audio's speaker amplifiers in October 2026, using the brand's own listings and US prices, so you can match the box to the system you actually have.
Quick take: If your source is wired and the budget is tight, start with the V3 or TB10D. If you stream from a phone, the BT20A Pro adds Bluetooth for $10 more than the bare V3. A subwoofer points you to the BT30D Pro or the BT20A MAX, balanced XLR sources to the ZA3, and a multi-channel or high-power system to a pair of V3 Monos. Want Spotify, AirPlay and multiroom with no phone pairing? That's the T10.
First, Two Things Every FOSI Amp Shopper Should Know
Most of these amps share one chip
The V3, TB10D, BT20A Pro, BT20A MAX, ZA3, V3 Mono and BT30D Pro are all built on Texas Instruments' TPA3255 Class D chip. That's why the headline power figures look so similar. The real differences are in what surrounds the chip: inputs, Bluetooth, cooling, balanced connections, subwoofer handling and the feedback design.
The power supply is part of the price
Many FOSI amps are sold bare or bundled with a 32V, 48V or GaN 48V supply. FOSI notes on the TB10D listing that its included 32V/5A adapter won't reach the amp's maximum output, and that a stronger supply such as 48V/10A is needed for that. If you're buying for big floor-standers, budget for the 48V option. Sold separately, the store lists a 32V 5A supply at $29.99, a 48V 5A at $59.99, a 48V 10A at $109.99 and a 48V GaN (240W) at $89.99.
→ Check the latest FOSI Audio coupon codes and deals
The Amplifiers, One by One
Pick 1: V3 Mini Stereo Amplifier (from $69.99)
The V3 is the purist's box: no Bluetooth, no tone controls, just a volume knob and a wired input feeding a TPA3255 chip rated at up to 300W x 2. The chip's heatsink is bonded to the case, with vents top and bottom, so the whole aluminum body sheds heat. Two swappable NE5532 op-amps can be replaced with SS3602, MUSES02 or OPA2134PA chips to change the sound.
US prices in October 2026: $69.99 bare, $85.99 with a 32V 5A supply, $105.99 with 48V 5A and $135.99 with a GaN 48V supply.
Pick 2: TB10D Stereo Amplifier ($79.99)
The TB10D covers the same ground in a more traditional layout, adding bass and treble knobs to the volume control. It's RCA-input only, with banana-plug binding posts that also accept bare wire. FOSI's spec gives 2 x 300W into 4 ohms at 10% THD and 2 x 150W unclipped into 8 ohms. The $79.99 price includes the 32V/5A adapter. Choose it over the V3 if you want tone controls without Bluetooth.
Pick 3: BT20A Pro Bluetooth Amplifier (from $79.99)
For most phone-first listeners, this is the sensible middle. The BT20A Pro keeps the TPA3255 chip and the swappable NE5532 op-amps, then adds Bluetooth 5.0 with pairing memory and wide-range bass and treble controls that you can park at the midpoint for the unaltered sound. FOSI lists SNR at 108dB or higher and THD at 0.005% or lower. It comes in Blue or Gray: $79.99 bare, $99.99 with 32V 5A, $129.99 with 48V 5A and $149.99 with a GaN 48V supply.
Pick 4: ZA3 Balanced Stereo Amplifier (from $109.99)
The ZA3 is for setups with a balanced source, such as a DAC or preamp with XLR outputs. It's FOSI's first amp with a combo XLR and 1/4-inch TRS balanced input and a 12V trigger input, so it can switch on with the rest of your system. It runs in stereo mode at up to 155W or mono mode at up to 235W, which means you can start with one and add a second later for a pair of mono amps. Tinkerers get five swappable op-amp sockets. FOSI lists SINAD up to 89dB and SNR up to 106dB.
US prices: $109.99 bare, $129.99 with a 32V/5A supply and $149.99 with 48V/5A.
Pick 5: V3 Mono Monoblock (from $109.99)
The V3 Mono drives one speaker per amp, rated at 240W into 4 ohms, and it's the first FOSI amp to use PFFB (post-filter feedback), which the brand says reduces the load-dependency issues common to Class D designs. FOSI lists THD as low as 0.006%, SINAD of 101dB and SNR of 123dB, with XLR/TRS balanced and RCA inputs. Use two for stereo, or add several to boost a multi-channel AV receiver. Pricing: $109.99 for one bare unit, $139.99 with a 48V/5A supply, $209.99 with 48V/10A, or $279.99 for two units sharing one 48V/10A supply.
Pick 6: BT30D Pro 2.1 Channel Amplifier (from $109.99)
Own a passive subwoofer? The BT30D Pro has two sets of speaker outputs plus a dedicated passive sub output, driven by two TPA3255 chips at up to 165W x 2 + 350W. Two knobs handle the bass: SUB FREQ sets the crossover anywhere from 0 to 300Hz, and SUB VOL sets the level. Bluetooth 5.0 is listed with a range of up to 15 meters. One note from FOSI: with a 48V supply, the amp needs active cooling, such as a fan. Prices: $109.99 with 32V/5A, $139.99 with 48V/5A.
Pick 7: T10 Wi-Fi and Bluetooth Amplifier ($129.99)
The T10 is the odd one out, and that's the point: it's built around network streaming. FOSI lists AirPlay, DLNA, TuneIn, Tidal, Qobuz and more, plus USB drive, NAS and AUX sources, and multiroom control across devices on one network. Output is 100W + 100W into 3 ohms, with a pre-out, a remote and a 24V supply in the box. It suits ceiling, garden or bookshelf speakers where you'd rather tap an app than pair Bluetooth.
Pick 8: BT20A MAX (from $249.99)
The MAX is the BT20A Pro with nearly every upgrade FOSI offers: PFFB and a dual independent power supply, a built-in silent fan (FOSI says 30% better cooling than the Pro), Bluetooth 6.0 with LDAC and aptX Lossless, dual RCA inputs, a subwoofer output, a 12V trigger, a high-pass filter and a motorized volume pot you can turn from the remote. It ships with a 48V 5A supply at $249.99, or a GaN 48V 5A supply at $279.99.
→ Check the latest FOSI Audio coupon codes and deals
Side-by-Side Comparison
| Amp | US price (Oct 2026) | Inputs | Good for |
|---|---|---|---|
| V3 | $69.99 bare–$135.99 | Wired | The lowest-cost wired system |
| TB10D | $79.99 (32V supply incl.) | RCA | Tone controls, no Bluetooth |
| BT20A Pro | $79.99 bare–$149.99 | Bluetooth 5.0 + wired | Phone streaming plus op-amp swaps |
| ZA3 | $109.99 bare–$149.99 | XLR/TRS + RCA, 12V trigger | Balanced sources; stereo now, mono later |
| V3 Mono | $109.99–$279.99 (pair) | XLR/TRS + RCA | One amp per speaker, AVR boost |
| BT30D Pro | $109.99–$139.99 | Bluetooth 5.0 + wired | 2.1 systems with a passive sub |
| T10 | $129.99 | Wi-Fi, Bluetooth, USB, AUX | Streaming apps and multiroom |
| BT20A MAX | $249.99–$279.99 | Bluetooth 6.0, dual RCA, trigger | A do-everything stereo hub |
Regional versions can be priced differently, so pick the US option at checkout, and see today's FOSI Audio deals before you choose a power supply bundle.
What to Know Before Buying
- Shipping: FOSI's shipping policy lists free standard shipping to the US by FedEx in 3–7 days. In-stock orders start shipping within 1–2 business days, and orders aren't processed on weekends.
- Order changes: to change the address or model, or to cancel, contact FOSI within 24 hours of placing the order.
- Returns: undamaged products can be returned within 30 days for a full refund. Return shipping is free for quality issues; after five return requests, the customer pays return shipping and a handling or restocking fee may be deducted.
- Warranty: the amplifier listings mention a 24-month warranty.
Pros and Cons
What we like
- A clear upgrade path, from a $69.99 bare V3 to a $279.99 BT20A MAX
- Bare-unit pricing if you already own a compatible supply
- Swappable op-amps on the V3, BT20A Pro and ZA3
- Balanced inputs and 12V triggers on the ZA3 and V3 Mono
- Free US shipping and a 30-day return window
What to watch
- Similar names and looks make it easy to order the wrong model
- Lower-voltage supplies limit maximum output
- The BT30D Pro needs a fan when run on 48V
- The V3, V3 Mono and ZA3 have no Bluetooth of their own
Who It's For, and Who Should Skip
Good fit: anyone with passive speakers and no amplifier, desk-setup builders, renters who want a full-size sound without a full-size receiver, and tinkerers who enjoy op-amp rolling or adding a second mono amp later.
Skip it if: you need HDMI video switching and surround decoding in one box, or your speakers are already powered (active) and don't need an amplifier at all.
How to Save on a FOSI Amplifier
- Member offer: the homepage advertises 10% off your first order when you join FosiCredits.
- Bundles: the Bundled Offers page advertises up to 15% off when you mix amps, speakers and accessories.
- Bare units: reuse a power supply you already own.
- Kits: the S3 Balanced streamer is offered as an S3 + ZA3 bundle for $469.99.
Before you check out, browse current FOSI Audio offers.
FAQ
Which FOSI amp has Bluetooth?
The BT20A Pro (5.0), BT30D Pro (5.0), T10 and BT20A MAX (6.0). The V3, TB10D, ZA3 and V3 Mono are wired.
Do I need the 48V power supply?
Not to get sound. But on the TB10D listing, FOSI notes that its included 32V/5A adapter won't reach the amp's maximum output and suggests a stronger supply such as 48V/10A. That matters most with large or hard-to-drive speakers.
Can I connect a subwoofer?
The BT30D Pro drives a passive sub directly; the BT20A MAX has a subwoofer output for an active sub.
What's the difference between the ZA3 and V3 Mono?
The ZA3 switches between stereo (up to 155W) and mono (up to 235W). The V3 Mono is mono only, rated at 240W into 4 ohms, and adds PFFB.
Final Verdict
FOSI Audio's amp lineup makes sense once you start from your system instead of the spec sheet. Wired and frugal: V3 or TB10D. Phone-first: BT20A Pro. Subwoofer: BT30D Pro. Balanced gear: ZA3, or a pair of V3 Monos. Streaming apps: T10. All of the above in one box: BT20A MAX. Choose the power supply that matches your speakers, then check the newest FOSI Audio savings before you pay.
Olivia Reviews researched FOSI Audio using its official website, product listings and published policies in October 2026. We haven't personally tested these products. We may earn a commission when you buy through our links, at no extra cost to you.