Amplifier enclosure question

woodro · Post by **woodro** » Sat Oct 29, 2005 12:00 am

hi guys, I'll be receiving an pallet amplifier (300w fm300-108 with mrf151G)
and have a question regarding setting it inside an enclosure.

I originally planned on putting the pallet along with a big heatsink inside a 4RU aluminum rack enclosure with a Lambda powersupply and low pass filter.

I have been told recently that I should not put the power supply for this amplifier inside the same enclosure because of power supply bypassing and shielding issues. I can understand if the power supply was an openframe type with no cover etc, but the Lambda i have has a cover on it along with a build in fan inside it.

I want to do this right, so i'm asking for suggestions on the best way of doing this. If the PA should be in its own enclosure (along with the low pass filter i presume) this means another enlcosure I guess for the power supply to live in. Looked on the net to find info and pics showing others who have done this but didn't find any.

This pallet is designed for 48vdc operation but was also told I could run it at reduced rf out using 28vdc which is what my intentions are. Your feedback and suggestions on this would be appreciated and very helpful. thanks in advance
W

woodro · Post by **woodro** » Mon Oct 31, 2005 11:06 pm

no one?

also, anyone have any experience with a Richardson type pallet amp
fm300-108 using a mrf151G? its operating voltage is supposed to be 48vdc but would like to run it at 28vdc and wondering if there is any prob with doing so...I realize the output power of the pallet would be reduced allot, but anything else that should be considered?

tks, W

Post by **pcs** » Tue Nov 01, 2005 12:02 am

It can be used in the same enclosure, but you have to use filtering
capacitors on outputs of the power supply. It is also nice to use
RFI filter on the mains connetor.

Using it at 28V will reduce its output by a lot, I recommend using
48V switcher, they come with voltage regulation anyway and you
can lower voltage to 30-40V easily.

woodro · Post by **woodro** » Tue Nov 01, 2005 1:32 am

thanks for the reply Marko. Your tips are noted and will be applied. As for the 48v supply, kinda been looking for something suitable that will fit inside a 4ru 19" rack enclosure but have not seen much in this size around. Most 48v supplies with any real amperage seem to be monsters. But I am persistant, and in no rush so I will keep looking around.

many thanks, W