# PSU - controller - led wattage and noise

#### erani

Joined Nov 15, 2020
5
Hi all,

I've got two led strips: a (A) 24V 167W RGB-CCT (6 wires) led strip and a (B) 24V 140W CCT (3 wires) led strip. I have tried to connect both to a Meanwell 200W power supply with a wifi rgb-cct controller in between that supports maximum 6A/Channel with a total maximum output of 15A.

There is a strange high pitch hiss sound coming probably from the power supply. I can hear this sound when putting the A led strip at maximum brightness and when I change brightness with the B led strip (from high brightness to lower one).

Do you know why there is this sound? could this be due to a not enough powerful power supply? or perhaps the problem is the controller?

I could also buy another power supply if necessary but I haven't found any rgb-cct controller more powerful than the one I've bought.

#### dl324

Joined Mar 30, 2015
14,905
Welcome to AAC!

My guess is a poorly designed switching regulator.

#### Bernard

Joined Aug 7, 2008
5,784
If all LEDs are on the drain is about 300 W which a 200W supply will not like. Best to use a 350 - 400 W supply.

#### erani

Joined Nov 15, 2020
5
Welcome to AAC!

My guess is a poorly designed switching regulator.
Thank you!

A switching regulator? mmm you mean about the PSU?

It should not be so bad as PSU. The following are the specs:

Code:
Mean Well RSP-200-24 AC / DC

power supply 200W DC 24V MeanWell power supplies of the LRS series are a line of high performance professional power supplies , with a perforated aluminum structure, with air dissipation .
They are suitable for continuous use and are also suitable for use in the industrial field.
This power supply features overload, overvoltage and short circuit protection .

The power supply is equipped with a Volt regulator (Vadj) which allows for an output voltage from 20V to 26.4V.
It is compatible with all led strips and devices withconstant voltage DC 24V .

FEATURES:
- Power: 201.6W
- Maximum Current: 8.4A
- Driver type: AC / DC
- Input voltage: AC 85-264V
- Output voltage: DC 24V
- Dimmable: no
- Number of outputs: 3 outputs
- Structure : aluminum
- Degree of protection: not waterproof IP20
- Operating temperature: -30 ° C + 70 ° C
- Effectiveness: 89.5%
- Dimensions: 215 x 115 x 30 mm
- Warranty: 3 years
- Certificates: UL60950-1, TUV EN60950-1 approved,
Compliance to EN55022 (CISPR22) Class B, EN61000-3-2, -3,
Compliance to EN61000-4-2,3,4,5,6,8,11, EN55024,
light industry level, criteria TO

#### erani

Joined Nov 15, 2020
5
If all LEDs are on the drain is about 300 W which a 200W supply will not like. Best to use a 350 - 400 W supply.
I'm not using both led strips at the same time. It's this the strange thing.. only one per time.

#### Dodgydave

Joined Jun 22, 2012
10,395
Hiss or high pitched whine is caused by the Inductor or Transformer being over driven.

#### erani

Joined Nov 15, 2020
5
for the "over-driven" thing, a more powerful PSU should be enough to fix it.. 250W still too low in your opinion?

#### erani

Joined Nov 15, 2020
5
I have an update. I've bought a new PSU (same brand of the other). This time 320W and IP65. No coil whine at all.
I have to understand now why the other PSU produces that noise at max brightness.

I would exclude now the controller. Two options are left:

1) it's because the PSU is not powerful enough
2) it's because the case is IP65, so that might reduce the noise
3) both of them