간단소식 AIYIMA 오디오 A70 스테레오 PFFB 전력 증폭기 TPA3255 300Wx2 클래스 D Hifi AMP 알려드립니다

Hightlight

 

【With PFFB design】AIYIMA A70 is the first stereo home audio Class D amplifier on the market based on the TI

TPA3255 chip with a post-filter feedback loop (PFFB),The A70 Class D amplifier with PFFB implementation,it have

no load dependency together with lower distortion

【With 12V Trigger Input & RCA audio input】The trigger input to allow one button power up of the audio chain

from the source,Simple and convenient; There is a switch to add 3 dB of gain to RCA input. This gain switch can be

used to boost the signal input at RCA inputs

【With balanced input】AIYIMA A70 Stereo Amplifier with XLR audio signal input ,This design minimizes interference and reduces noise floor

【With RCA & Sub output】Add the sub output with variable filter output,The sub output is controlled by the volume setting,and Added adjustable cutoff frequency (20-150hz/20-600hz) for low-pass filter output,Easily build 2.1-channel Audio systems to match any of your desktop speakers

Specification

Chipset: TPA3255+NE5532

Replaceable op-amp chips: RT3609SM, OPA2604, OPA2134, LM4562, JRC5532, OP275GSZ, OPA1612 ect.

Distortion: 0.0015% (@ 1W)

Signal-to-noise ratio: ≥ 116 dB

Frequency Response: 20Hz-20KHz (±1dB)

RCA input sensitivity: 1.9Vrms (25 dB)/1.1Vrms (28.5 dB)

XLR Input Sensitivity:3.8Vrms (19dB)

Speaker Impedance: 4-8Ω

Stereo Output Power: 2x300W (@4Ω) 48V10A

Input Mode: RCA+XLR

Supported devices: decoder, bile preamp, computer, CD, cell phone, MP3, etc.

Output mode: 2.0 passive speaker + active low-pass

Working power supply: 36-48V

Package included:

1*A70 amplifier

1*Manual

1*Power plug(It's optional)

We see a nice boost in SINAD as predicted, landing the amplifier essentially in our "excellent" category:

RCA input has fair bit lower performance but still above average:

Note that I adjusted the volume down to 25 dB per my recent standard of testing amps (used to use 29 dB).

Noise performance is excellent:

Despite its lower gain with XLR input, you can still reach full power at 3.3 volts which is well below nominal 4 volts we see out of majority of DACs. So I am good with that.

Let's jump into frequency response as that is the other big deal:

We see a bit of frequency dependency but it is outside of our hearing range.

I set the subwoofer output frequency to the lowest and measured this:

Crosstalk is extremely good:

Good performance numbers give way as you go up in higher frequencies in multitone and especially in 19+20 kHz IMD:

Let's see how much power we have:

That's a lot coming out of this little box. We are talking nearly 360 watts total. 8 ohm output is naturally lower:

Edit: as noted, performance does degrade above certain frequency:

My reactive load doesn't like these bridged amps. The issue seems to be in one channel so I left that disconnected and drove only one:

The amplifier is specified down to only 4 ohm but seemed robust enough to even handle 2 ohms, albeit with a good bit of voltage drop. Translating the above into watts we get:

For those of who want to use these amps in mono, you now have that information as well.

There is likelihood of a turn on "pop" but turn off noise is completely eliminated:

Finally, amplifier was essentially ready to go on power up: