2SC2879 vs. 2SC3240

[kopcicle]

I'm sure this isn't what you want to hear but I'll say it anyway.
12 to 13.8V+ is a dead issue. That ship has sailed.
There is no such thing as a 2SC2879 today or even in the last 3 years. Okay there is HG...

Even if it wasn't a dead issue , the 2x8 is equally a non starter.
Even a pair of the venerable 2SC2290's or a pair of MRF455's are going to be capable of nearly 80 watts. Would you really want to drive a hypothetical (read here imaginary) 2SC2879 with 10 watts AND keep it linear for SSB use?

Now if all you wanted was a Class C maul then have at it .

Again, 12V (or wtf ever) is a dead issue, get over it .

MRF101A(B)
https://www.nxp.com/products/radio-...mrf101an-rf-essentials-kit:MRF101AN-START-KIT
MRF300A(B)
https://qrpblog.com/
or the art for my unfinished amp

MRFX1K80H
https://www.ebay.com/itm/174819992492
https://www.ebay.com/itm/313493736321

So here's the deal. Get over 12V.
Mobile
Take 4 batteries and charge in parallel , discharge in series.
This isn't optimum by any means but it's an option.

Use the China Bay boost converters. You'll need about 12 of the so called 600 watt bricks. and they make a bunch of RF noise so it's a keying sequence puzzle.

Run a secondary 50V charging system. This is probably the best alternative. just find a place to put a second alternator.

Couple of things that go largely unmentioned here.
Five times the voltage , one fifth the current.
Many radios have a keyup overshoot issue even if the output has been turned down.
The gates (input) in these devices are fragile. It's best to drive them with an input that is running flat out at it's maximum output.

Okay, the NXP data sheets are available online. You may have to register but ...
I have a few industry contacts for the active devices that won't overcharge the crap out of you so if you get serious just ask.

And last but not least the bang for the buck is
Razvan @ https://qrpblog.com/. accessories like the LPF board and others are there as well.

One last time. 12V is a dead issue.

Gee I hope I offended someone

 

[9C1Driver]

Getting ready to have a 2x8 built.
I really need transistor advice for Type 2-30 MHz SSB Linear Power Amplifier.

Clean output Signal is #1.

Please advise
Thank You

What amp builder are you going with? The two that come to mind right now are Hopper built and Carl built. I think BBI also makes amplifiers. With the limited options and availability of finals your stuck with what ever the builder has on hand or prefers to use. Is this a mobile or base amplifier? Why a 2x8?

 

[Crawdad7]

Lesters Customs is the builder, Amp is coming up for build in the next couple mths. we're in final discussions on the build. Base NOT mobile, Originally was 2X4 High Drive as I'm only interested in 1000watts clean output, running cool & efficient. RCI2995 Base is also part of this creation were working on. All advice is greatly appreciated considering the changes in the last 2 years. Should of had one built 5 yrs ago! Lot going on or NOT in the transistor world. I have spent countless hrs reading on this site & find most of these folks here the regular commenters quite intriguing!

 

[Crawdad7]

What amp builder are you going with? The two that come to mind right now are Hopper built and Carl built. I think BBI also makes amplifiers. With the limited options and availability of finals your stuck with what ever the builder has on hand or prefers to use. Is this a mobile or base amplifier? Why a 2x8?

Lesscom Hornet coming up for build in the next couple mths. we are in final discussions on the build. Base NOT mobile, Originally was 2X4 High Drive as I'm only interested in 1000watts clean output, running cool & efficient. RCI2995 Base is also part of this creation were working on. All advice is greatly appreciated considering the changes in the last 2 years. Should of had one built 5 yrs ago! Lot going on or NOT in the transistor world. I have spent countless hrs reading on this site & find most of these folks here the regular commenters quite intriguing!

 

[Shadetree Mechanic]

A 2x4 doing 1000w won't be clean. If you want 1000w clean, you will need a straight 8. The 2x will overdrive anything less than a 10 transistor amp.

 

[Crawdad7]

A 2x4 doing 1000w won't be clean. If you want 1000w clean, you will need a straight 8. The 2x will overdrive anything less than a 10 transistor amp.

A 2x4 doing 1000w won't be clean. If you want 1000w clean, you will need a straight 8. The 2x will overdrive anything less than a 10 transistor amp.

In todays market WHAT transistor would you use. Lester has Chinese Toshibas 2879's & HG 2879's he will stand behind. What's left MFR454 /MAcom?

 

[Shadetree Mechanic]

The HG is the best replacement for the Toshiba that is available. The HG do a fine job, but I have heard that they are not as robust as the Toshiba was. I currently have two 4 pill amps with HG and they do great in the 5 to 6 hundred watt range. The drive on the input of a 4 pill should be around 40 to 60 watts peak. I would never put 100w into one of them, but people on YouTube do and show crazy numbers on the output.