Dual final mod on a DX959? Thoughts?

[The Jerk]

See, I thought that was the picture of the inside of an amp, not a stinger board...things didn't register at the time. Interesting, I will need to see if there is anyone around who can do that mod.

 

[Brake Weight]

It's pretty much the guts of their 203 amp is my understanding. I don't know how well it'd do on ssb. I think there's a few YouTube videos on them.

 

[ExitThirteen]

The KL203 and AD203 amps are class C, and will sound bad on SSB. If you plan to run SSB, I wouldn't recommend going with this setup. A local of mine bought two of them, thinking they'd work on SSB, so he installed one, and it sounded horrible.... and the neighbors complained. So he uninstalled it, and gave them both away. Ended up getting a Killer Bee 250HDV (T/S 250 HDV) and runs that instead. No complaints, and crystal clear on SSB.

The AD203 would be ok for AM use.


~Cheers~

 

[The Jerk]

I'm thinking if I go with a stinger board, then I have two other radios I can use...one is a PC76 the other is a PC78W...so SSB would not be an issue. But I'm still concerned about RFI (since most new cars are susceptible)...I'd probably be able to under drive it in order to prevent RFI? See what I come up with...

 

[psycho]

I'm thinking if I go with a stinger board, then I have two other radios I can use...one is a PC76 the other is a PC78W...so SSB would not be an issue. But I'm still concerned about RFI (since most new cars are susceptible)...I'd probably be able to under drive it in order to prevent RFI? See what I come up with...

My thoughts on doing a dual final mod to a 959 or installing a stinger board in ANYTHING.................

 

[The Jerk]

Why not? That's why I posed the original question...

 

[Brake Weight]

My thoughts on doing a dual final mod to a 959 or installing a stinger board in ANYTHING.................

Bored? Curious? Hobby? Why not?

 

[Robb]

Here is how you install a dual-final mod in a 959, courtesy of CB Tricks:

http://www.cbtricks.com/miscellaneo.../galaxy_dx949_959_2547_erf2030_mod_rev1-2.pdf


You could use the IRF-510's or the better IRF-520N's instead of the ERF-2030's. Use mica insulators with heat sink compound instead of the ceramic insulators. Get and install a heat sink on the back of the radio across the back of the finals; you will need it now. Galaxy can sell you the heat sink and it is made to fit this radio BTW. Make sure it is flush/flat across the back surface of he radio!

You can also make the companion EN-369FN and EN-369DR devices too:

You may also consider changing out the 2SB754/70 watt voltage regulator in this radio; as it might be strained or even fail due to the high current demand of these MOSFET output devices when you change them over. The 2SB817 is a 100 watt regulator; just don't buy any of the phony ones from China on eBay. Buy from an American dealer and get a genuine Sanyo device. Cost is about $8.

Get rid of the ceramic insulator behind it as well, and get a mica insulator for it. Use decent heat sink compound too. This will transfer far more heat out of the device. You will find this regulator along the right side of the chassis frame.

Hope that helps.

EDIT:

Q37 is a 2SA473; it can be improved by installing a TIP42C in its place. IIRC, it is the audio driver - it will improve AM modulation. You will find it facing the 2SB754 freestanding on the board.

This dual final MOSFET mod should have clean output, so long as you don't over-modulate or over-drive the output. If you buy IRF-520N's, make your own companion parts, and buy the heat sink from Galaxy, I'm guessing that you could probably build it for around $20. Depending on how much Galaxy wants for the heat sink. Should be about 60 watts of fairly clean output.

 

[2RT307]

The KL203 and AD203 amps are class C, and will sound bad on SSB. If you plan to run SSB, I wouldn't recommend going with this setup. A local of mine bought two of them, thinking they'd work on SSB, so he installed one, and it sounded horrible.... and the neighbors complained. So he uninstalled it, and gave them both away. Ended up getting a Killer Bee 250HDV (T/S 250 HDV) and runs that instead. No complaints, and crystal clear on SSB.

The AD203 would be ok for AM use.


~Cheers~

ExitThirteen, when I emailed RM Italy, they told me the 203P was A/B biased. I found it hard to believe, especially when they are available for 50 bucks at h and y. I am not as technically gifted as you, so you may "see" something different on the board than what they are saying. I have not played with mine much, but was running my Uniden Grant XL at stock power through the amp, and seeing about 100 watts out with the amp. I did not have time to get any radio checks to see how it sounded.

73,
RT307

 

[9C1Driver]

Yeah, I just don't want to install an external amp...was trying to figure out if adding a second final to a radio I already own was better than buying a dual final radio. My biggest fear is this new truck will suffer from RFI if I go to big or if I have something that's not clean. I have three radio choices, the 959 is the only one that can have the dual final mod done.

I have a lead on a Stryker 447HPC for $175 locally, but I'm reading its a single "flange-mounted" transistor, which indicates its like a 2290/2879? Thinking it would be too much? Again, my fear is RFI in this new truck.

The RM KL-203 is decent bang for the buck, as stated they do ok on SSB and are very much a low drive amp. Add a fan too.


Any of those "Stinger" boards, mosfet or 1446 final, are junk and cause many problems once installed. That would be my absolute last choice.


Doug at Custom cb does a nice dual final mod in the 959.


I would probably do an RFX-75 on the 959 before anything, just remember you will only get maybe 70 watts PEP. That's about 125 bucks to double your watts.


To be honest, if you need an all in one package that does higher watts I would sell the 959 and find a higher powered Export.


The Galaxy 959 to me is an average radio at best and would not be my first choice anyway.

 

[ExitThirteen]

ExitThirteen, when I emailed RM Italy, they told me the 203P was A/B biased. I found it hard to believe, especially when they are available for 50 bucks at h and y. I am not as technically gifted as you, so you may "see" something different on the board than what they are saying. I have not played with mine much, but was running my Uniden Grant XL at stock power through the amp, and seeing about 100 watts out with the amp. I did not have time to get any radio checks to see how it sounded.

73,
RT307

Interesting!
They must have changed this on their latest revision, as the ones that friend had were class C. Perhaps the newer ones might be ok then!

On topic, I'd go with something external still, and not get the dual final mod done. 9C1Driver has a good point, the Galaxy radios are subpar, and really not worth putting extra money into. The Uniden PC76 and 78's are a far better radio if you're going to just run AM only.

The Stryker 447HPC has a 2SC2290 in it. As long as you don't remove the modulation limiter, and it has a proper peak & tune, you shouldn't have any trouble with the radio.


~Cheers~

 

[psycho]

Bored? Curious? Hobby? Why not?

Let's see.......a stock tuned 959 might swing 20 watts. A 959 with a dual final mod might swing to 35-40 watts peak. Do you think going through all that is worth it, I sure don't.
Stinger boards are notoriously problematic.

 

[The Jerk]

On topic, I'd go with something external still, and not get the dual final mod done. 9C1Driver has a good point, the Galaxy radios are subpar, and really not worth putting extra money into. The Uniden PC76 and 78's are a far better radio if you're going to just run AM only.

The Stryker 447HPC has a 2SC2290 in it. As long as you don't remove the modulation limiter, and it has a proper peak & tune, you shouldn't have any trouble with the radio.


~Cheers~

See that's my problem...I have several good radios, but nothing that should be cut up for this other than the PC78 and the DX959 (they are expendable to me). And I just don't want the install of an external amp this time around...my PC76 and 1x4 were a well matched set in the last truck, but again; I don't know if this new truck would take the RFI.

That's the reason I was thinking about the dual final mod for the 959, but I knew very little about it. Now I am seeing that's not a real option, from either a performance standpoint, or a performance/$$ standpoint. I've never been a fan of this 959...never really thought it sounded that good; so maybe this will inspire me to buy another radio.

I was looking at the RFX-75, but it was my understanding they are dirty? That's the reason I hadn't really considered one.

I wish they just made a straight AM dual final radio; without the extra channels...sort of like a no bells, no whistles Connex 3300HP in a Uniden PC76 chassic. I don't need (or want) all that extra BS that most exports have...give me a standard meter, volume, squelch, RF Gain, mic Gain, echo, 40 AM channels, and call it a day.

 

[suzerain]

Let's see.......a stock tuned 959 might swing 20 watts. A 959 with a dual final mod might swing to 35-40 watts peak. Do you think going through all that is worth it, I sure don't.
Stinger boards are notoriously problematic.

Absolutely worth it!
Looks to be an hour of work or less, and with the new regulator and audio driver suggested earler will do even more.
Who wouldn't want to kick their amp with 50W of PEP instead of 15?
And with just an hours work that will kick that amp for years to come?
Just install the 2 switch freq mod and save yourself buying a 99V. Oh yeah.

Seems a no brainer to me.

 

[RADIOOMAN]

Absolutely worth it!
Looks to be an hour of work or less, and with the new regulator and audio driver suggested earler will do even more.
Who wouldn't want to kick their amp with 50W of PEP instead of 15?
And with just an hours work that will kick that amp for years to come?
Just install the 2 switch freq mod and save yourself buying a 99V. Oh yeah.

Seems a no brainer to me.

You're gonna have to 'show' the math on this one.
Looks like you knocked the 20 down to 15 and then somehow bumped the 35-40 up to 50.
Are you familiar with the term 'gain compression'?
Gain compression is term that describes the 'non-linear' function between driver input power and amplifier output power.
At some point of driving the amplifier with more power you start to realize 'diminshing returns' and where the effective gain of the amplifier drops back to nearly zero db gain.

In case you're still wondering where I stand on this: NOT WORTH IT