Author Topic: MFJ ALS 500  (Read 66 times)


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« on: February 24, 2017, 02:25:48 PM »
MFJ ALS 500 Solid State Amplifier.

For those of you wanting to increase your power a few S units we have many amps to choose from these days. MFJ has pretty much cornered the market with Expert a close second with their solid state entries. 

If you are thinking about an amplifier of some sort this is my take on the offering of the ALS 500. This amp claims a PEP of 500 watts and  key down output of 400 watts, not bad, for 100 watt transceivers  this will give you an increase of 6 DB or one S unit and a fraction of another s unit that will go unnoticed on the receiving end. Another positive is plug and play, no tuning, just hook up the needed cables and go.

However, there are some interesting factors to consider before you think about using this amp in a fixed station location. The biggest obstacle is you need a separate power supply for this one, MFJ will sell you a 75 A power supply for this purpose. Now, before I hear all the moaning and groaning about power supplies, consider this. On peaks the ALS 500 will hit around 70 amps, with a 75 amp supply you have some head room. This is a common sense practice with all applications and considered good engineering practice.

MFJ does state that this amp is made for mobile use, based on the amperage needed for your car you better have a good electrical system and be capable of having an output of 75 amps on peak.

Another draw back to this amp is 12 volt FET finals, these are heading to the obscurity of changing times and Technology. With 24 Volt FETsí you have double the voltage and reduced the amperage, therefore smaller power supplies are needed.

For home use with this amp letís consider price it sells for $949 plus $259.95 for the power supply, that comes to $1208.95 for 400 watts CW or key down modes, or 500 watts PEP.  The only thing it offers is no tune and solid state, a much better buy for home use is the AL 600, yet in this case you will see a six db gain and again a fraction of another S unit barely noticeable on the receiving end of the contact.

A very good buy in this case would be the 811H amp, yes it is tubes, but tubes that will not cost you an arm and leg to replace. This amp offers 800 watts peak and about 600 watts Key down. However, forget about running on 120AC, make the switch and use 220 Volts I have covered the reasons why in a former article.  In this scenario you will gain 9 db with a hundred watt rig that equates to an s unit and a half of another one.

If you must have higher power then consider all the possible prices, wattage and if it will be practical for your station. If you want solid state no tune amps, look at the MFJ 1.3 and of course the Expert 1.3. Consider also the MFJ according to ratings and reviews it spent a lot of time in the brown truck going back and forth to MFJ for repairs. The Expert was far more reliable. Your choice depends on you and you alone, your budget may not allow more expensive purchases, so buy what you can afford. I personally would avoid the 500 and go for something else, namely a built in power supply, plus more output power.

Consider also the 811h sells for just under 1000 and offers more power, plus it has a built in power supply, not bad for the price. The choice is indeed yours.