Opinion on IMG Stage line STA-400D amplifier with Hypex modules

[WinWiz]

I had some noctua low noise adapters and 40x40 fans left from another project. So decide to (hopefully) improve the cooling a bit...

 

[WinWiz]

Also applied a generous amount of cooling paste between heatzink and case, and made cool new home with a temperature controlled 140mm fan for the stageline 400d

 

[WinWiz]

The noctua fans caused some noise in the left channel. I think it was caused by the taco pulse signal. So I rearranged the cables making sure the yellow wire from the fan runs far away from the amp/input sections.
Also decided to measure the variable voltage fan connectors. Voltage seems regulated by the power supply temperature. When the amp is cold the fans run at 8,5V, increasing to about 22V when the amp is very hot. I actually think the stock 24V fans are decent -but you can definitely hear them at 8.5V
My noctua fans are 12V so I decide to mount two pots to regulate the stock fan voltage.
First pot regulates the two fans cooling the amp heatzink while the second pot regulates the fans in the power supply region (right side inside amp).
I tuned the pots so the fans runs slow and SILENT when the amp is idle. When the amp works hard the fans runs kind of loud but at high volume output I don't notice the fan noise.
So now I'm very pleased with my slightly modified amp

 

[WinWiz]

If anyone wants an easy way to decrease the speed/noise of the stock fans. I pretty sure you could just remove the thermal paste on the temp. sensor placed at the end of that small plastic tube running vertical from the amps front to the psu...

 

[WinWiz]

Monacor made a new revision of this amp with updated input buffer. New design looks cleaner but I don't have expertise to tell if it's actually better.

 

[Martini.from.Italy]

Hello, I also use these ultra-cheap pro amps with good satisfaction.
Besides the sta-400 I have a sta-1000 (Pascal modules, I had two in bridge) and a sta-2000 too.
They are great class D amplifiers, excellent for the price (often much lower than the official one).
They are silent, heat up little and the fan rarely plays. (on the sta-1000 it never starts).

Then I have Behringer in class AB, ep4000 and ep 2000; it's a different sound.

 

[WinWiz]

My sta-400 had noisy fans -and the fans startede spinning like 10 seconds after power on. So I returned the sta-400, but my second sta-400 behaved the same way.
You say they heat up a little. Have you tried touching left side of the bottom (bellow the heat zink) ?? Aften a while it gets unpleasantly warm.
I purchased a defective yamaha receiver and used the larger cabinet, heatzink and two temperature controlled 80mm fans to solve the noise/heat issues.
For an old yamaha 5.1 reciever the sound is amazing -but of course now it only outputs left and right channels

 

[Martini.from.Italy]

Honestly I was surprised that they do not heat up much. I must have heard the fan spin two or three times.
It is true that I mainly use the sta-1000 with Pascal modules which instead is always cold.

Well. you did a good job recycling a larger cabinet .

p.s .; I also have an img sta-700 in class ab and in this case the fan starts by default and runs strong as soon as it is turned on; same thing happens on the behringer (but on the ep2000 I detached it and I removed the lid, since it does not heat much)