SMSL’s TPA3255 All-in-One DAC/Amplifier - AL400

[Guddu]

SMSL also jumps onto TPA3255 amp space now, quite a package of features in this small unit:

Note- They haven’t mentioned PFFB, so it’s unclear but possibly not deployed.
Frequency response graphs aren’t available as well.

 

[Guddu]

Priced @275$

 

[SlowJim]

Great price but LPF should say HPF, no? Every powered sub on earth has LPF built in.

 

[MCH]

eARC, interesting. Probably irrelevant in this application but still interesting to see.

 

[pieterv1]

This looks great! As most (if not all) SMSL products it seems to be missing a 12v trigger input though.

Can anybody comment on (automatic) power on/off functionality of these devices? Is there some sort of auto-sensing feature for the analog and digital inputs?

Asking because I'm thinking about pairing this with a WiiM Ultra - fed from the USB output.

 

[John.D]

SMSL also jumps onto TPA3255 amp space now, quite a package of features in this small unit:

View attachment 495830

View attachment 495831

View attachment 495832

View attachment 495833
View attachment 495834

Note- They haven’t mentioned PFFB, so it’s unclear but possibly not deployed.
Frequency response graphs aren’t available as well.

Rightly said, quite a package.
I will look forward to a test, are you planning?

 

[Guddu]

This looks great! As most (if not all) SMSL products it seems to be missing a 12v trigger input though.

Can anybody comment on (automatic) power on/off functionality of these devices? Is there some sort of auto-sensing feature for the analog and digital inputs?

Asking because I'm thinking about pairing this with a WiiM Ultra - fed from the USB output.

SMSL haven't mentioned it anywhere, so most likely there is no auto ON/OFF on signal sense.

 

[Roland68]

SMSL also jumps onto TPA3255 amp space now, quite a package of features in this small unit:

View attachment 495830

View attachment 495831

View attachment 495832

View attachment 495833
View attachment 495834

Note- They haven’t mentioned PFFB, so it’s unclear but possibly not deployed.
Frequency response graphs aren’t available as well.

Nothing really new; these devices were already available as the SMSL AS400 and the Loxjie A40, both featuring the Infineon MA5332MS and NJW1194A.

It would be nice if they managed to integrate the TPA3255 better than the TPA6120a2, but the measurements will show that.
In any case, it's an alternative to the Infineon amplifiers.

 

[pieterv1]

Lol I thought the backside was looking familiar!

 

[daniboun]

Now @ Audiophonics

SMSL AL400 Integrated Amplifier 2.1 DAC Black

The SMSL AL400 is an integrated amplifier and DAC featuring high-performance architecture based on a TPA3255 amplifier chip and a Cirrus Logic CS43131 converter

www.audiophonics.fr

 

[Shiva]

Might this device, have an option to turn off the amp section and run it as a preamp… if desired…

 

[Roland68]

Might this device, have an option to turn off the amp section and run it as a preamp… if desired…

No, because the device doesn't have a preamp output, just like other similar devices from SMSL and Loxjie.
You would have to hack the device and tap into the low-level signal that drives the power amplifiers and route it externally. With such a complex device, especially one controlled and monitored by an MCU, I would advise against doing that.

SMSL seems to be overlooking the fact that there's a market for exactly this kind of device—without a power amplifier but with preamp outputs.
You could also look into a small AVR or the corresponding AV preamps from Canton and Nubert.

 

[EJ3]

Great price but LPF should say HPF, no? Every powered sub on earth has LPF built in.

Not everyone uses active powered subs. They are, of course, active but not with built in amps. Each one has it's own amp. And an FR of only 20Hz-80Hz.

 

[Kitty (S.M.S.L Marketing)]

Thanks for sharing. The circuit is not publicly available; please click the link to view more information：https://www.smsl-audio.com/portal/product/detail/id/935.html

 

[Guddu]

Thanks for sharing. The circuit is not publicly available; please click the link to view more information：https://www.smsl-audio.com/portal/product/detail/id/935.html

I hope you can help in finding couple of answers for us, these are kind of common questions on TPA3255 based amplifier here:
1) Does AL400 use PFFB circuit?
2) Do you have frequency response graphs for 4 & 8 ohm loads?
3) What is output impedance of AL400.


BTW, I did reach out on FB asking same questions (first two questions) but don’t think those were answered there.

 

[HalSF]

A tempting candidate for my desktop setup with active speakers and sub.

Would much prefer a second RCA input rather than a built-in phono preamp. And what’s the deal with still touting MQA as an appealing and valid feature people are clamoring for in 2026?

Would SMSL sell even one less unit it it didn’t offer MAA?

 

[Roland68]

A tempting candidate for my desktop setup with active speakers and sub.

Would much prefer a second RCA input rather than a built-in phono preamp. And what’s the deal with still touting MQA as an appealing and valid feature people are clamoring for in 2026?

Would SMSL sell even one less unit it it didn’t offer MAA?

There are indeed a large number of uninformed customers out there regarding MQA who have read or heard somewhere that it's the best recording format and is used everywhere in recording studios.

I give Topping a lot of credit for no longer including or promoting it.
However, I find SMSL's behavior regarding MQA extremely unethical.

 

[DazST]

Great price but LPF should say HPF, no? Every powered sub on earth has LPF built in.

So is it actually a low pass (sending low frequencies to sub) or high pass filter (removing low frequencies from mains)?

 

[Kitty (S.M.S.L Marketing)]

I hope you can help in finding couple of answers for us, these are kind of common questions on TPA3255 based amplifier here:
1) Does AL400 use PFFB circuit?
2) Do you have frequency response graphs for 4 & 8 ohm loads?
3) What is output impedance of AL400.


BTW, I did reach out on FB asking same questions (first two questions) but don’t think those were answered there.

Hi,
Here are a few clarifications:

1. The PFFB implementation details are not publicly disclosed.
2. The updated frequency response chart is now available.
   You can view the full measurements here:
   https://www.smsl-audio.com/portal/product/detail/id/935.html
3. The damping factor of the AL400 is 74.

 

[DazST]

Hi,
Here are a few clarifications:

1. The PFFB implementation details are not publicly disclosed.
2. The updated frequency response chart is now available.
   You can view the full measurements here:
   https://www.smsl-audio.com/portal/product/detail/id/935.html
3. The damping factor of the AL400 is 74.

Thanks Kitty. Any chance you could also clarify the unit's bass management capabilities (low and high pass filters)?