Hi,
Meanwell seem to have a good name for these brick type smps with regard
to noise, not that they are perfect or don't need help in some
situations though.
I have recently been working on an SPE Expert 2K-FA amplifier. This has
2 smps units, one is unknown but the drain supply for the amplifier
devices is a Meanwell RSP-3000-48, 48 volts at 62.5A. This required
attention as it was refusing to start due to gecko infestation. Once
cleaned the unit runs well and is near silent in the audio department.
It has 2 fans at one end and these do come on when the power supply is
switched to operating mode but behind the main equipment fan filter
these do not make much of a sound.
Supply to the psu comes from the AC input to the amplifier and attention
has been paid to AC line filtering. 2 large ferrite tubes, approximately
2.5 inches long and 0.75 inch diameter are wrapped with about 6/7 turns
of the live and neutral supply wires before these go to the psu input
terminals. The SPE has minimal filtering on the output of the psu as all
connections are to the internal amplifier modules and these are
contained inside the double screened enclosure of the amplifier.
The Meanwell supply is almost totally enclosed with heavy aluminium
shielding and in the SPE amplifier this is then enclosed in the outer
clamshell aluminium case. The supply is on all the time the amplifier is
in the operate condition but switches to a standby mode when the
amplifier is in the bypassed state.
My own very limited investigations reveal no additional noise above
background nominal but my location may not be the quietest to begin
with. Either way it seems perfectly fine. I have not heard of complaints
related to psu noise from these or similar amplifiers so I would suggest
that if you pay the same amount of attention to the input filtering as
SPE do then noise might be fine.
In summary I would think that the Meanwell supply might make a good
choice for a smps unit with a few caveats:
1. Put it in a box that provides additional good screening.
2. Ensure the input AC feed line is well filtered with an appropriate
amount of ferrite and wire.
3. If the output leads are long and exposed you may (most likely)
need to add output filtering.
Many amateur high power solid state amplifiers are using switch mode
supplies and I think there would soon be a slew of complaints if the
messed it up. In closing I will say I was very impressed with the SPE
Expert amplifier. Build quality is excellent and far better than the
average amateur product and aside from a slightly old style display and
dead feel touch buttons the whole thing is a quality product, definitely
on my buy list.
Martin, HS0ZED
On 18/7/63 00:07, Bob D. wrote:
I've been using a HP server supply, 12.5 V 100A or a marine battery to
power a Tentec 420 amp. I'd like to have the collector voltage at full spec
so am considering a Meanwell 15 V 100 A supply.
If anyone knows, I'd like to learn:
Noise levels from this supply.
Source of an inexpensive enclosure.
How well it works if powered on and off between transmissions.
-bob ah7i em73ts
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