guddu478
Active Member
BT20A Max - Fosi's first TPA3255 PFFB Stereo Amplifier
Quick highlights:- TPA3255 PFFB based stereo amplifier with active FAN inside case over amplifier chip assembly and remote control
Front Panel
- Motorized Volume, Bass, Treble controls knobs
- Multifunction Button: Power ON/Off & input selector
Back Panel
- Input: 2 x RCA inputs, Bluetooth (QCC3095)
- Output: Speaker Out, Sub-Woofer out
- HPF Toggle: 80 Hz fixed High Pass filter, Two Settings: 80Hz or OFF
- 12v Triggered input, tone bypass button & DC Power input (32-48v)
Packaging & Contents
- BT20A Max amplifier Unit, remote control, power supply and manual.
Build Quality, Look & Feel
- Case shows nice build quality with some color tone combination, looks really good.
- Remote feels plastic and works well.
- Bass & Treble knob / potentiometer are quite smooth running with center/middle stop which probably indicate 0 or neutral value.
- Motorized volume works nicely, responds to remote without any issues.
- Spacing between connectors is good enough for heavy cables & interconnects.
- The case is heavy enough not to be dragged by heavy cables.
Note: Tone Bypass bypasses Bass & Treble, however Volume Control remains variable.
Active FAN under the hood
BT20A Max has active always-ON fan under the case over the metal heat sink to help better cooling the amplifier chip. “MAX” cutout the top does helps with the air going out as well.
Fan does show its presence with faint noise which might be audible from closer distance when nothing is playing. However, it isn’t a concern with music playing.
Idle Power
- About 16watts idle when no music is playing.
- Note that it may remain around 16watts under low listening volumes as well.
My setup & Pairing
Speakers: Revel M16, these are 6 Ohn speakers but dip down to 4 Ohms.
With both 48v 5a or 48v 10a PSU, BT20A Max worked fine without much sign of heat.
Overall, I found the output signature to be quite neutral. This combination is detailed, balanced and punchy. It could get these Revel extremely loud without signs of any stress with 48v 5a PSU.
A quick look at any difference in frequency response in my setup & room, UMIK-1 stays at the same location and sweep levels were voice-matched:
Fosi BT20A Max vs 3e A7 vs Aiyima A20, HPF OFF
Subwoofer-Out and HPF: 80 Hz
- Subwoofer-Out is main volume controlled and has roll off starting around 80 Hz to 150Hz complete cut-off
- When HPF is ON, subwoofer-out has 4-5 dB higher gain compared to when HPF is Off
Performance wise, it did work very well for Revel M16 speakers with subwoofer out.
Bluetooth Output
Bluetooth connectivity was easy and totally stable. I never had any issue at all connecting with any devices I used with like iPhone 16, Windows Laptop, nVidia Shield Pro, Google TV box etc.
Sound quality wise, surely inferior compared to a nice DAC connected on RCAs but that’s reasonable.
It is more like a convenience feature than HiFi.
Triggered Input
12v triggered input also worked very well without failure or initial sync issues.
*No compatibility issues with Wiim products, worked fine with Wiim Ultra.
Summarizing my observations and thoughts
BT20A Max has better build quality than other similar ones, heavy case with nice finish and decent spacing between connectors. It does not run more than slightly warm, however the internal FAN is always ON which does show its presence with faint sound.
Front light is quite dim and so doesn’t attract eyes unnecessarily, but it is also then a bit difficult to find input looking at LED in bright room.
Sound Quality is as good as any other good TPA3255 PFFB amplifier, almost neutral and quite powerful.
Most importantly, I totally liked 2 RCA inputs which is more practical in my opinion. Making it good option for me to compare 2 different RCA inputs like 2 DACs, Pre-Amps etc.
Overall, definitely worth a look and try.
