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MaxPro1 Rf Transistor Upgrades
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MaxPro1 Rf Transistor Upgrades
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andido
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Post Reply with quote
Where can i find an NTE-342?
I've done a search for UK sources with NO results.
Is it actually worth swapping the 2SC1971 for a NTE-342?
Sun Jan 15, 2006 10:36 pm View user's profile Send private message
pcs
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Post Reply with quote
I don't think so.

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Sun Jan 15, 2006 11:52 pm View user's profile Send private message Visit poster's website
andido
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Post Reply with quote
You're the man who made the board... and if you say nope i'm happy to go with that!
I can imagine it taking me months to finally get one, and then after fitting there'd be no difference!!! Oh well.
I'm buying a MaxPro 3 or 4 soon when i've decided which anyway.
Mon Jan 16, 2006 12:39 am View user's profile Send private message
pcs
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Post Reply with quote
I recommend MAX PRO 4 in that case.

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Mon Jan 16, 2006 2:23 am View user's profile Send private message Visit poster's website
cliffyk
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Post Reply with quote
andido wrote:
Where can i find an NTE-342?
I've done a search for UK sources with NO results.
Is it actually worth swapping the 2SC1971 for a NTE-342?


I wouldn't do it just for the sake of doing it--I fried my OEM output and couldn't find any 2SC1971's over here in the colonies--I got one NTE342 from a Statside vendor, than had 5 on order for nearly 3 months 'til I got them last week. Of course the one I have in service will last forever now...

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Mon Jan 16, 2006 4:27 am View user's profile Send private message Visit poster's website
Norwalk Electronics
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Post 2SC2539 = 17 watts out with 500 mw in @ 14.5 db Reply with quote
This would not be a project for a beginner since it would require mounting a transistor with a different case style and pin out. With this in mind if you can mount the 2SC2539 to the heat sink and wire it in with the shortest, low inductance wire possible..... the 2SC2539 is an ideal high power replacement for the 2SC1971. It is true larger transistors often require more drive power but if you choose one with significantly higher gain, it is possible to get more output without increased drive or more stages. If we look at the specs for the 2SC1971 we see it makes 7 watts output with 600 mw drive. The device has a gain of 10 db. The 2SC2539 makes 17 watts output with only 500 mw drive because it runs at 14.5 db in VHF service. Imagine that, more then twice the output with 1/10 of a watt less drive then the 2SC1971!
Mon Jul 10, 2006 7:47 am View user's profile Send private message Visit poster's website
andysuttle
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Post Reply with quote
Could a 2SC2539 be applied to a MaxPro1 board with absolutely no other alteration other than correcting it's pin-out???
Sun Nov 12, 2006 9:53 pm View user's profile Send private message
andysuttle
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Post 2SC2539 -replacing the stock 2SC1971 Reply with quote
I located a 2SC2539 however i didn't realise it was a VERY much different package type.
In theory i could connect this to a MaxPro1, but how different are the pin-outs to the 2SC2539.
It's sepc sheet and pin-outs are locate here: http://www.datasheets.org.uk/search.php?q=2SC2539&sType=part


Can anyone help or comment?

I'd really like to fit one of these as i can purchase one for £5 only, which makes it a lot cheaper than having to buy a 15watt amplifier!
Tue Nov 14, 2006 12:13 am View user's profile Send private message
cliffyk
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Post Reply with quote
Providing detailed information for re-engineering the MaxProI to use the 2SC2539 would be a decidedly non-trivial task, and as the fellow from Norwalk Electronics stated;

Quote:
"This would not be a project for a beginner since it would require mounting a transistor with a different case style and pin out. With this in mind if you can mount the 2SC2539 to the heat sink and wire it in with the shortest, low inductance wire possible."


Also, and well beyond the physical and "low inductance" lead issues, there would undoubtedly be other changes, tweaks, and considerations required (such as interstage impedance matching, power supply, etc.)--which often with a one-off retrofit project require more effort, prototyping, and experimentation than would a "ground-up" design.

My point is that I do not believe this is the sort of project that anyone with the knowledge and expertise required is going to spend several hours thinking about, several hours prototyping, and several hours experimenting with--to provide the information you seek and make it available for free in this venue.

Then again, I could be wrong...

There are a number of amplifier designs using the 2SC2539 available on the web, constructing any one of these would be easier than retrofitting a MaxProI...

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Tue Nov 14, 2006 1:25 am View user's profile Send private message Visit poster's website
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