Fosi Audio BT20A Pro Bluetooth 5.0 Amplifier, 300W x2 Wireless Amp, TPA3255 2 Channel Mini Class D Integrated Home Audio Outdoor Stereo Receiver $89.99 @Amazon

SociableJuice4504

Jun 13, 2026 10:07 AM

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Joined Sep 2020

SociableJuice4504Jun 13, 2026 10:07 AM

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$99 to $90 is not slick in the least. Weak.

12

tgif

Jun 13, 2026 2:33 PM

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Joined Sep 2004

tgifJun 13, 2026 2:33 PM

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Comes with a 32v/5A power supply. So...160W? 300Wx2 isn't adding up.

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MaartenT

Jun 13, 2026 4:40 PM

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MaartenTJun 13, 2026 4:40 PM

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Quote from tgif

:

Comes with a 32v/5A power supply. So...160W? 300Wx2 isn't adding up.

Yes like most of these amplifiers with an external power brick the specs are a little deceitful. 2 * 300 Watts is the amount that the chip can handle. A much more potent power brick Will be needed to reach those numbers.

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Halfy

Jun 13, 2026 5:00 PM

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Joined Apr 2011

HalfyJun 13, 2026 5:00 PM

12 Comments

Quote from tgif

:

Comes with a 32v/5A power supply. So...160W? 300Wx2 isn't adding up.

Somewhere they have a spec sheet and they are only rated for 150w with the included power supply

1

delzinga

Jun 13, 2026 5:17 PM

469 Comments

Joined Oct 2014

delzingaJun 13, 2026 5:17 PM

469 Comments

From the bowels of the Amazon product page:
*Note: It should be emphasized that 300W refers to the maximum power supported by the product's chip, which can only be achieved with a 48V 10A power supply. The power supply's voltage and current determine the amplifier's maximum output. For more details, please refer to the illustration below on Power Variability.

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ucbengr

Jun 13, 2026 5:59 PM

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Joined May 2005

ucbengrJun 13, 2026 5:59 PM

3K Comments

$48 for the 48VDC/5A power supply

https://www.amazon.com/Audio-Supp...0F54N3FX3/

so $80+$48 = $128 to get the higher power rating. plus you get the 32V 5A Power supply to toss in your drawer maybe for some future need. doesn't seem too slick.

Last edited by ucbengr June 13, 2026 at 11:03 AM.

2

SaveAndThrive

Jun 13, 2026 8:00 PM

267 Comments

Joined Jun 2011

SaveAndThriveJun 13, 2026 8:00 PM

267 Comments

We have been running another similar Fosi amp daily in our home theater system for years. Reliable unit and it sounds pretty good. These little amps can impress.

1

jmate

Jun 13, 2026 9:03 PM

162 Comments

Joined Jan 2017

jmateJun 13, 2026 9:03 PM

162 Comments

Upgrading this to the MUSES02 op-amp (or if you're feeling adventurous, the Burson Audio V7) does make the amp a tad warmer/smoother. Else this is a clean/clinical amp for small to mid sized speakers. 48V power supply recommended.

1

TealPen595

Jun 13, 2026 9:47 PM

30 Comments

Joined Feb 2020

TealPen595Jun 13, 2026 9:47 PM

30 Comments

Quote from ucbengr

:

$48 for the 48VDC/5A power supply

https://www.amazon.com/Audio-Supp...0F54N3FX3/

so $80+$48 = $128 to get the higher power rating. plus you get the 32V 5A Power supply to toss in your drawer maybe for some future need. doesn't seem too slick.

When I got one these years ago I also bought this PSU. This is perfect for these things, esp if your running more than 1. https://www.amazon.com/dp/B08GFQZ...le_32&th=1 48v 10A

tgif

Jun 13, 2026 11:26 PM

999 Comments

Joined Sep 2004

tgifJun 13, 2026 11:26 PM

999 Comments

Quote from delzinga

:

From the bowels of the Amazon product page: *Note: It should be emphasized that 300W refers to the maximum power supported by the product's chip, which can only be achieved with a 48V 10A power supply. The power supply's voltage and current determine the amplifier's maximum output. For more details, please refer to the illustration below on Power Variability.

The max voltage for that Texas Instruments integrated circuit is actually higher: 53.5 and output at 315W, but I'm sure it would need way better cooling than a sealed aluminum housing to run that high. FOSI makes a twin chip 2.1 unit, which would want a 48v/20A power supply...lol@that price tag! $100?
TPA3255: https://www.ti.com/product/TPA3255

Last edited by tgif June 13, 2026 at 04:28 PM.

q_businessman

Jun 14, 2026 10:55 AM

96 Comments

Joined Sep 2009

q_businessmanJun 14, 2026 10:55 AM

96 Comments

Perhaps a kind slickdealer could help, I'm looking for an amp that could drive four JBL Control 25 speakers in my shop. They have an impedance of 8 ohms with 150 watt "continuous program power capacity". Would this amp and power supply be able to drive these well? Speaker specs and details always confuse the heck out of me. TIA!

AquaVolcano980

Jun 14, 2026 1:13 PM

387 Comments

Joined Sep 2022

AquaVolcano980Jun 14, 2026 1:13 PM

387 Comments

Quote from q_businessman

:

Perhaps a kind slickdealer could help, I'm looking for an amp that could drive four JBL Control 25 speakers in my shop. They have an impedance of 8 ohms with 150 watt "continuous program power capacity". Would this amp and power supply be able to drive these well? Speaker specs and details always confuse the heck out of me. TIA!

The cheapest way would be to buy a used receiver from a second -hand store like Goodwill or Salvation Army for around $40, which will have "A" and "B" speaker connections for stereo playback and should be able to handle using both sets at the same time. If you want a smaller amp like the one in the post, you could use a speaker switch box like this https://www.amazon.com/Improved-S...217&sr=8-3, which will keep the impedance from going too low and damaging the amp. I have an old Sony receiver hooked up to three sets of speakers in my garage with a similar switch box from Monoprice (which appears to be discontinued) and that setup has worked well for many years.

1

q_businessman

Jun 15, 2026 2:01 AM

96 Comments

Joined Sep 2009

q_businessmanJun 15, 2026 2:01 AM

96 Comments

Quote from AquaVolcano980

:

The cheapest way would be to buy a used receiver from a second -hand store like Goodwill or Salvation Army for around $40, which will have "A" and "B" speaker connections for stereo playback and should be able to handle using both sets at the same time. If you want a smaller amp like the one in the post, you could use a speaker switch box like this https://www.amazon.com/Improved-S...217&sr=8-3, which will keep the impedance from going too low and damaging the amp. I have an old Sony receiver hooked up to three sets of speakers in my garage with a similar switch box from Monoprice (which appears to be discontinued) and that setup has worked well for many years.

Thank you so much for the reply! I'll try to go this direction 👍

ucbengr

Jun 15, 2026 8:25 AM

3K Comments

Joined May 2005

ucbengrJun 15, 2026 8:25 AM

3K Comments

Quote from TealPen595

:

When I got one these years ago I also bought this PSU. This is perfect for these things, esp if your running more than 1. https://www.amazon.com/dp/B08GFQZ...le_32&th=1 48v 10A

more than 1? are you running 2 as a 4 channel system or is there some way to bridge them and run each as a monoblock?

onirrapdivad

Jun 16, 2026 12:49 AM

234 Comments

Joined Nov 2014

onirrapdivadJun 16, 2026 12:49 AM

234 Comments

Chi-fi at its best. I have the non-Bluetooth version of this amplifier and it sounds great, takes up very little space and it is what I reach for whenever I find a pair of speakers at the thrift store or a garage sale.
Definitely fun to tinker with different chips as they are friction mounted in a socket instead of soldered. Loads of fun for the price. $90 is a pretty good deal for these as I paid $80 without Bluetooth years ago. If you are looking to power some passive speakers, look no further.
Also, you can use a more powerful brick to push it to 300W per channel but I don't think it is necessary.

Fosi Audio BT20A Pro Bluetooth 5.0 Amplifier, 300W x2 Wireless Amp, TPA3255 2 Channel Mini Class D Integrated Home Audio Outdoor Stereo Receiver $89.99 @Amazon

$90

$100

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