BLF574 Power Amplifier 600w does this look any good?

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Elopid
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BLF574 Power Amplifier 600w does this look any good?

Post by Elopid » Mon Mar 08, 2021 7:07 pm

Hi there all, I recently found a nice bargain for just £100 on eBay!
https://www.ebay.co.uk/itm//133502324188
Unfortunately it was the last one for sale so I very quickly smashed the buy it now button and here it is...
Although it was being sold as for FM broadcast I can't help noticing on both of the boards it says "225MHz"
Obviously I will need a decent LPF but do you think this will be any good? I am worried it's designed for the much higher frequency but as there is no 225MHz LPF will it work on the FM broadcast band??
Hopefully it should work OK, what do you guys think?
600w amp 1.jpg
600w amp 2.jpg
600w amp 3.jpg
600w amp 4.jpg
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yellowbeard
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Re: BLF574 Power Amplifier 600w does this look any good?

Post by yellowbeard » Mon Mar 08, 2021 7:59 pm

That looks to be the broadband design from the BLF574 datasheet which is 225MHz. There is an 88-108 design for that tranny - search AN10714 - it's not the same. You will need a filter or your second harmonic will be humongous.

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Electronically
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Re: BLF574 Power Amplifier 600w does this look any good?

Post by Electronically » Mon Mar 08, 2021 8:01 pm

Yea It can do between 10 to 500mhz. but I would recommend lpf for final stage

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Elopid
big in da game.. trust
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Re: BLF574 Power Amplifier 600w does this look any good?

Post by Elopid » Mon Mar 08, 2021 9:00 pm

Thanks for the replies guys. Yes sorry for any confusion about LPF's, when I said "Obviously I will need a decent LPF but do you think this will be any good?" I meant I would only use it with an LPF if connected to an antenna.
I am hoping to test it soon into a dummyload without LPF and if it's working ok then I will add a 1kW LPF.
I was just worried that this board was only for use around the 225MHz band and wouldn't work on the FM broadcast band.
Thanks for clearing this up.
I will post my results after testing in the next few weeks.

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