Galaxy dx-2527 mosfet mod

[ExitThirteen]

Keep in mind that if you were to put Mosfets in the radio, you also have to upgrade the pass regulator transistor, the 2SB754, to something like a 2SB817 or a 2SB827, to handle the higher current draw from the Mosfets.

Honestly, I'd keep the original bipolar transistor finals in it, if the radio works as it should. The time/money that you's have to invest into the radio to modify it, plus the potential power supply issues to gain an extra 5-10W PEP really isn't worth it. Send it to a good tech and get a good alignment with a P&T and let it talk.



~Cheers~

 

[Greatvalue1]

What's wrong with just getting a linear?

 

[Lil'Yeshua]

959 board

You could see what components are on the 959 board and duplicate it. The 959's have 2SB827's If I'm not mistaken. Plus have a 10 amp ps. op:

 

[Zman]

And Davemade audio is louder too.

darn right it is!!!! he heee heeee!

 

[Zman]

Its called trying to convince yourself all the time and money wasted did more than just adding a 40W linear did.

So if you're convinced you are correct perhaps you can give me a technical explanation as to why?

Not time and $$ wasted. I like to mod my stuff. Why knock someone that does something that you don't agree with? everyone is different and not everyone does the same thing.

Most of the radios i mod perform better than stock and are by far louder than stock. Most of my customers are very happy with their radios after i mod them. I haven't had one come back yet!!!! My specialty is the Cobra 25 and 29 after i add the mosfet they are really loud!

 

[basstracker1970]

What if i did the mosfet change and then unhooked the internal power supply and ran it to my ps-36kx power supply. I have already upgraded to the 2sb817 regulator and the am amp to a 2sa1012 and install all schottsy diodes in the nb and receive. The mosfets do put out a little more swing but they also put out alot more louder and cleaner modulation. That is what im looking for that punch of pure clean modulation that only the mosfets can produce...

 

[9C1Driver]

What if i did the mosfet change and then unhooked the internal power supply and ran it to my ps-36kx power supply. I have already upgraded to the 2sb817 regulator and the am amp to a 2sa1012 and install all schottsy diodes in the nb and receive. The mosfets do put out a little more swing but they also put out alot more louder and cleaner modulation. That is what im looking for that punch of pure clean modulation that only the mosfets can produce...

In the end it is your radio, if you want to mod it up go for it. As a general rule working radio's usually only need a correct tune and alignment. You can add receive and audio mods as well as extra channels.

With all due respect to the Z Man I am not seeing mosfet finals as an "Audio mod", they are finals. Now when combined with say a swing kit or compression mod then yea the radio will sound louder. You could add the Top Gun Modulator or the SP1-A speech processor to that radio as is and be much louder too with the stock finals.

If you do go for it remember, the mosfets are not a drop in replacement. There are other things that need to be re-engineered and modded to make it work. By the time you get done dinking around with the power supply your radio will be a keeper. No one will want to buy it used because it will be all janked up.

 

[Lil'Yeshua]

Basstracker:

I think QROdx pretty much made the right point. Even if you put these MOSFETs in the radio, the power supply in your radio cannot support the amount of extra current that these devices will require/draw. Your power supply will presently only provide about 5 amps continuously. If your radio has an external 13.8v source and a switch to use an external power supply, you would need to get a power supply that can handle about 10 amps @13.8v. You can't get something for nothing . . .

Not to mention, that if you have never done this kind of mod before you may too easily get it wrong. I say this because you said 'are they a drop-in replacement'? No; they are not drop-in replacement. Not really for a beginner to do. They also need to be properly adjusted and even require additional cooling from a heat sink with perhaps even a cooling fan. A Cobra 29 or 25 is an easy place to start for a MOSFET mod - IMO.

I'm not familiar with base stations. Does it have a stiffening cap at the power supply? If so,then would you need to put a larger value cap in? In my latest car stereo project,I installed a 1 farad stiffening cap next to the amplifiers. That caused the sub freqs hit a whole lot harder. My thoughts are that a larger cap at the ps on your radio would make it do at least as good as a 959. Also,are the caps in the radio large enough to handle the mosfet transplants you are thinking about doing?

 

[Lil'Yeshua]

now that's a cap!

I'm not familiar with base stations. Does it have a stiffening cap at the power supply? If so,then would you need to put a larger value cap in? In my latest car stereo project,I installed a 1 farad stiffening cap next to the amplifiers. That caused the sub freqs hit a whole lot harder. My thoughts are that a larger cap at the ps on your radio would make it do at least as good as a 959. Also,are the caps in the radio large enough to handle the mosfet transplants you are thinking about doing?

My 959 is run off the fuse block on this amp rack with a 4 gauge stranded wire going into a short section of inline fuse and Galaxay style power plug. Hardly any voltage drop and the 959's meter light doesn't. Hardly dim at all on modulation.

 

[9C1Driver]

As a general rule Bat Caps work great for car stereos but not so well for cb. I suppose with just a barefoot radio it would be fine. Most people will try to run them with a big amp to try and fix the lack of voltage due to too small of an alternator. With a stereo amp the steady drum beat lets the cap re-charge. With a cb you key the mic and drop that 300 watt carrier and the cap is gone in 2 seconds. It will not re-charge until you stop talking.

 

[Lil'Yeshua]

gone in 2 second.

That's what I thought as well after I made that post. My thoughts at that time was how could he make that base radio hit as hard as a 959 mobile. Someone else mentioned that a bigger power supply was needed if he put mosfets in. I'm unfamiliar with base stations. Does the power supply have some kind of cap that goes with it? If so,I was thinking that a bigger cap was needed.

 

[Lil'Yeshua]

I was thinking about a smoothing cap in a power supply. I used a set of caps to smooth out the voltage on a train transformer I used to power a 12 volt dc fan. That worked because it brought the voltage up enough to run the fan. I'm learning. Thanks. http://www.kpsec.freeuk.com/powersup.htm