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Palomar Electronics Max-Mod. Spoiler alert!

nomadradio

Analog Retentive
Apr 3, 2005
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www.nomadradio.com
A check of the Palomar Electronics web site turns up only two products. Their new mike and a fat plastic PNP power transistor marked "Max-Mod".

https://www.palomarelectronics.com/product-page/palomar-max-mod

As for the 'spoiler' part. I'm fairly sure that this is a re-branded part "2SA1301". We have used these to reduce failures in radios that get used on SSB a lot. Not hard to fit into a base radio, but might be a bit tight in a mobile.

It has a larger metal surface on the rear than the original 2SB754, 688, 827 and such parts. And that's the half the battle to reduce the part's operating temperature. A bigger contact surface produces less temperature rise per Watt by transferring heat more efficiently.

The other half would be a bigger heat sink. That's why we have used it mainly in base station radios. A mobile chassis just doesn't have the surface area to bleed away that heat. Didn't seem worth the extra expense when the heat sink is already too small.

More and more people are getting impatient for Eric to get the Magnum product line moved over to the new Palomar name. Checked in and found this part alongside his new hand mike.

Couldn't resist spoiling the mystery.

Now if only someone could crack the original type number that they scraped off their "ERF7530" MOSFET, that would be really cool!

And Eric, if you read this feel free to chime in and contradict me if you like. No hard feelings.

73
 

Educated guess. Voice of experience.

Could be wrong. It might not be a 2SA1301. Might be a 2SA1302.

2SA1301 is rated for 12 Amps and 120 Watts. Nearly double the original-design 2SB754.

2SA1302 is rated for 15 Amps and 150 Watts. But this one costs more. And that's why my bet is on the cheaper 2SA1301. That number has been easier to find, so it's the one we have been using for this purpose for a long time.

There are only so many plastic transistor types sold in that package. My 1998 japanese cross-ref book shows 2SA1303 (Sanken), 2SA1492 (Toshiba) and 2SB1347 (Matsushita) as subs for the 1301.

Shows Sanken 2SA1492, Toshiba 2SA1943 and Matsushita 2SB1317 as subs for the slightly-larger 2SA1302.

That leaves us seven possible types to meet the general description of a "Max Mod".

Might be more. We only covered three manufacturer's product lines here.

73
 
Or, just go with a TIP35C/36C (NPN/PNP).

Rated at 100V, 25A (40A peak), 125W.

Been using these as a replacement in the (junk) exports for years now. They run cooler, and can handle so much more current for as cheap as $1.50 apiece, depending on where you buy them. I hope people don't buy into the snake oil of these "Max-Mod" transistors. :)


~Cheers~
 
Main advantage of the larger transistors is that they have a larger surface area against the heat sink. This lowers the thermal resistance of the heat path from the transistor to the heat sink. Results in fewer degrees temp rise per Watt of heat.

But yes, those ratings are perfectly appropriate.

But wattage rating alone is just part of the story. Dumping the heat from it matters, and a larger surface area does that more effectively.

73
 
Yeah, that's true.

Never given it much thought before, but I suppose that's because I've never had one get hot enough.

Could put in a small piece of aluminum between the insulator and the chassis to reduce heat by doubling the thickness of the transfer area.


~Cheers~
 
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I don't want to mention any names but I know someone that purchased some of these from Eric and they do perform as advertised and generate much less heat, so I wouldn't exactly call them snake oil, so perhaps someone could make us a video showing one of the cheaper Regulators performing in an identical manner to the one that Eric is selling. I would love to think that it's possible to purchase an identical component for a fraction of the price for the same performance.
 
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Given that Eric doesn't own a semiconductor factory, you can be sure that his part is produced by one of the companies who DO own a semiconductor factory.

You can also be sure that the part he buys and puts his number onto is also sold elsewhere with the manufacturer's original EIAJ number on it. The numbers that all start with "2S".

The only "cheaper" part is the number of middlemen between you and the factory. A part with that factory-original part number has at least one less middleman taking a cut of the price.

The published specs are probably trustworthy. That alone should dispel any suspicions of "squeaky snake" fixes.

Eric is free to charge whatever he likes. He's a legit businessman, and what he does is called "entrepreneurialism". I wish him only continued good fortune.

And anyone who wants to "go around" a middleman and buy stuff direct at a lower price is free to do that, as well. Doesn't make that same product any less legitimate.

Eric's transistor contains no secret sauce. It's just a mass-produced part with a new number printed on it.

73
 
Everything you said makes perfect sense and sounds totally logical and I am inclined to agree, but convincing this person that Eric's transistor is nothing more than a rebadged version from another manufacturer seems to be challenging at best. Once he finds a component that does what he's trying to achieve it's hard to convince him to try something different and compare the results.
 
Nothing wrong with brand loyalty.

But when I hear a driver say "I'll never own another Connex. It's just a cut-down Galaxy."

You'll soon hear another one saying "I'll never own another Galaxy. It's just a cut-down Connex".

And if either of them knew that the circuit board in each radio comes off the same production line it might or might not affect his opinion.

73
 
Nothing wrong with brand loyalty.

But when I hear a driver say "I'll never own another Connex. It's just a cut-down Galaxy."

You'll soon hear another one saying "I'll never own another Galaxy. It's just a cut-down Connex".

And if either of them knew that the circuit board in each radio comes off the same production line it might or might not affect his opinion.

73
I agree, I just think it's completely irrational to spend an extra 5 bucks per unit if someone can get that same transistor for $1.50 somewhere else with a different number on it.
 
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Irrational, yes.

Found this pic I snapped of the inside of that mystical secret-sauce radio the "General Lee". Still brings a smile.

KAVHHt.jpg


73
 
I just watched this video, and if I was a consumer I would gladly pay the $8 just to eliminate 60° of heat from my radio. The increased power wouldn't be the selling point for me. Even if the radio was retuned back to the factory power level just the reduced temperature would be reason enough for me to use that component. It would be cool if somebody could make a video similar to this one showing a drastic temperature change using a component that only costs $1.50.
 
You're not eliminating heat. Thermodynamics still apply. You're simply moving the heat energy out of the transistor and into the heat sink more efficiently.

The transistor must still throw the exact, same wattage. The job it does still boils down to being a current-controlled resistor in line with the final and driver. Ohm's law is what causes it to get hot in the first place.

The transistor runs cooler when it can dump the heat energy into the heat sink more efficiently. But the heat sink is still absorbing the same wattage of heat energy, just more efficiently. Odds are that the heat sink temperature will be higher than it was with the smaller transistor.

But a transistor that runs at a lower temperature should last longer.

That part of the picture really is that simple.

73
 

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