SMSL PA400 GaN 500W

[ianjams21]

I want to share my experience with this "product".

I first ordered an SMSL PA400 from Amazon. Shipping was fast and the total price was around €540 including delivery. Unfortunately, right after turning it on, I noticed that the control knob was defective. Volume adjustment worked, but the selector function didn’t respond at all. I contacted support about the issue.

While waiting for the refund, I ordered another PA400 from AliExpress using a discount coupon. The price was €380, plus customs fees later. When the second unit arrived, the situation was even worse — after a few minutes of use, the amplifier started randomly shutting down.

This says a lot about the quality control of these devices. Support claims that every unit is tested before shipping, but based on my experience, that clearly isn’t true. Faulty units are being sent to customers.

What really pushed this over the edge is that today a friend of mine, who bought this amplifier based on my recommendation, told me that his PA400 also started shutting down randomly after about a month of use.

I’m extremely disappointed with this brand, their products, and their attitude toward customers. Shipping unreliable equipment like this is unacceptable.

I strongly recommend avoiding this brand.

My unit also has started randomly cutting off after around 2-3 weeks of use. This is very disappointing.

 

[ianjams21]

My unit also has started randomly cutting off after around 2-3 weeks of use. This is very disappointing.

Anyone else got around to resolving this problem? I'm past the return window and can't get warranty on this unit in my local country.

 

[Roland_606]

Anyone else got around to resolving this problem? I'm past the return window and can't get warranty on this unit in my local country.

Also another thread discussing a similar fault to yours Here

 

[Joyck888]

having the same sound cut in and out problem from one of the mono amplifier. New firmware could fix this problem? I see 1.01 release

 

[Joyck888]

The latest firmware is 1.02, which fixes the problem with cutting in and out for now. No problem for now. I know one of my monos has a heat pad to cover it, but the one that is having problems does not have a heat pad. So far, so good. The update was not difficult.

 

[ianjams21]

The latest firmware is 1.02, which fixes the problem with cutting in and out for now. No problem for now. I know one of my monos has a heat pad to cover it, but the one that is having problems does not have a heat pad. So far, so good. The update was not difficult.

How do you go about with the update?

 

[Joyck888]

Open the bottom case. USB C and update. Simple. I did add some additional thermal pads to the units. One of the unit's thermal pads was not making any contact. Now no more problem. Anyone have problem with REL sub high-level feed from the amp? I am getting humm and thump.. regardless of grounding and floating.

 

[Roland68]

Open the bottom case. USB C and update. Simple. I did add some additional thermal pads to the units. One of the unit's thermal pads was not making any contact. Now no more problem. Anyone have problem with REL sub high-level feed from the amp? I am getting humm and thump.. regardless of grounding and floating.

Which grounding?
In all the pictures of the PA400's interior, the power plug's grounding is not connected.

If, as with most SMSL devices, the housing is not isolated from the device's ground, operation in the EU is not permitted and can be dangerous in the event of a power supply failure.

 

[Joyck888]

so far.. no luck with high-level input for REL. Low level works well, but my preamp volume is too low for the sub.

 

[Tim Yi]

My SMSL PA400 generate a pop noise whenever turn it on. Does anyone face the same issue? I do not know how bad it is to the speaker(8ohm)...

 

[NTK]

My SMSL PA400 generate a pop noise whenever turn it on. Does anyone face the same issue? I do not know how bad it is to the speaker(8ohm)...

Welcome to ASR!

I'd suggest take a look at the woofer when you power on the PA400 and see if the woofer cone moves a lot. If not, the PA400 is not sending a large amount of DC to your speakers, which is not audible (excluding the initial pulse/step).

If no significant DC is sent to the speaker, then how loud is the pop? Is it louder than the loudest sound you'd play during your listening sessions? If not, then the pop should not be anymore damaging than your normal listening to them.

 

[Emvy]

The latest firmware is 1.02, which fixes the problem with cutting in and out for now. No problem for now. I know one of my monos has a heat pad to cover it, but the one that is having problems does not have a heat pad. So far, so good. The update was not difficult.

Where do you see that the latest firmware for pa400 is 1.02? The most recent one I can find available online is 1.01

Edit: Never mind, SMSL's website incorrectly lists the file as 1.01 but after updating the FW with this latest file listed on SMSL's website my PA400 shows current FW version as 1.02 (to check FW version go to reset in the menu)

 

[Roland_606]

My SMSL PA400 generate a pop noise whenever turn it on. Does anyone face the same issue? I do not know how bad it is to the speaker(8ohm)...

I have two PA400s running in mono and they both produce a low level pop/click in each speaker several seconds after initial power up. They are silent on shutdown. I don’t see it as an issue because it is not at a level that would do any damage.

 

[ROY_H]

I'm trying to update the FW on my PA400 as I've been suffering the switch offs. I'm a little confused, I've downloaded and extracted the two .smsl files, copied them onto a USB memory stick. I connect the amp via the usb-c connector to my computer and memory stick, go into update mode as per instructions but it doesn't go into the active update mode (rotating icon?) Instructions say copy FW to USB drive, do they mean somewhere else like the C: drive ?

 

[Roland_606]

I'm trying to update the FW on my PA400 as I've been suffering the switch offs. I'm a little confused, I've downloaded and extracted the two .smsl files, copied them onto a USB memory stick. I connect the amp via the usb-c connector to my computer and memory stick, go into update mode as per instructions but it doesn't go into the active update mode (rotating icon?) Instructions say copy FW to USB drive, do they mean somewhere else like the C: drive ?

Caveat: I haven’t attempted the update yet for my units so I am only going off what AI is quoting. “Extract the .zip or .rar to the computer desktop.”

 

[ROY_H]

Right, thanks to Roland_606 for some advice. Here's how I've achieved updating my PA400 from 1.00 to 1.02 !

Download and unzip the two .smsl files (DMSL APP.smsl ; DFU DATA.smsl ) I saved them to Desktop where I could find them easily!.
Attach the amp via the internal USB C connector to your computer USB.
Enter the UPDATE mode as per SMSL instructions.
Your computer should now see the amp as a drive, mine was shown as F: but will vary. You should see a README file already there !
Copy the two .smsl files to this new location.
Switch off then enter the Update routine again. You will see a new screen with two bars across the screen and the update icon of two circular arrows.
You should now see the update progress with the bars showing the progress
Once the update has completed the amp will switch itself to normal working mode !!

I switched off then back on and entered the reset page which showed I had successfully updated to 1.02. I pressed reset just to be sure !

I'll let you know if it's sorted the switch-off problem I had once I get a chance to put it back into my system

Hope this helps others !!

 

[Bernard23]

I purchased two PA400s to replace my FOSI V3 mono amplifiers, driving my Linton 85th in the living room (listening distance 4.5m) and the Klipsch RP600 Mii in the bedroom (listening distance 2.5m).
They'll arrive this afternoon, and I hope for a favorable outcome. I appreciate their aesthetic design, and I have greater confidence in SMSL's circuitry. I consider SMSL a superior brand compared to Fosi and Topping, as they don't blindly pursue static specifications. (Although early SMSL products, like Topping, did obsessively chase extreme static metrics—a tendency that made me overlook the brand. Fortunately, SMSL seems to have moved away from that approach. Naturally, in this forum environment, such a shift wouldn't earn them favorable reviews.)

What was your conclusion?

 

[ROY_H]

Right, thanks to Roland_606 for some advice. Here's how I've achieved updating my PA400 from 1.00 to 1.02 !

Download and unzip the two .smsl files (DMSL APP.smsl ; DFU DATA.smsl ) I saved them to Desktop where I could find them easily!.
Attach the amp via the internal USB C connector to your computer USB.
Enter the UPDATE mode as per SMSL instructions.
Your computer should now see the amp as a drive, mine was shown as F: but will vary. You should see a README file already there !
Copy the two .smsl files to this new location.
Switch off then enter the Update routine again. You will see a new screen with two bars across the screen and the update icon of two circular arrows.
You should now see the update progress with the bars showing the progress
Once the update has completed the amp will switch itself to normal working mode !!

I switched off then back on and entered the reset page which showed I had successfully updated to 1.02. I pressed reset just to be sure !

I'll let you know if it's sorted the switch-off problem I had once I get a chance to put it back into my system

Hope this helps others !!

I can now confirm that the update to FW 1.02 has cured the random switch-off on my PA400.

I can also say I'm well impressed by sound quality !

 

[Roland_606]

I can now confirm that the update to FW 1.02 has cured the random switch-off on my PA400.

I can also say I'm well impressed by sound quality !

That’s good news! I’m still debating updating the firmware even though my PA400’s have not had the cutting out issue.

Also, thanks for the comprehensive instructions for FW update.

 

[Roland_606]

Since my previous post, one of my units decided to randomly switch into standby state. No problem, i just followed the update procedure to Ver. 1.02 as kindly described in this thread. No issues and seems to have solved it. Whilst I had the software downloaded I thought i would update my second PA400 which has been operating fine. I took the rear cover off, plugged in the usb C and attempted to put the unit into update mode. No dice! Seems the push function on the rotary encoder was bust and I was unable to bypass normal powering of the amp, as per instructions. As i had the case open, it was a straightforward task to unplug the various cable connectors, remove the switching power module and unscrew the pcb with the surface mount rotary encoder. Careful of the ribbon cable i was able to probe the pads and legs of the encoder. Sure enough, one of the two legs was unsoldered to its pad. Quick solder, put it all back together and then the update went smoothly.

Photo of the internals for anybody interested.