new GAN amplifier

Output stage, the stage before the output stage, hopefully the feedback network, the bias circuitry for the output stage ..... It's a different amplifier.

Can you even buy TO3 transistors any more? (TO3, as opposed to TO3P which is a different beast). I think with the exception of MIL they have all been long obsoleted.

It's a different amplifier.

Sorry, same amp with different output/driver stage and bias change.That allows one to directly compare same amount of Mosfet devices to the same amount of BJT devices

Can you even buy TO3 transistors any more

Of course you can don't be an *****, and they're still cheap and plentiful,  just look around.https://www.ebay.com/itm/1pairs-OR-2PCS-Transistor-MOTOROLA-TO-3-MJ15003-MJ15004-100-Genuine-Origina...

End of story, no more on this as it's not about the title "new GaN Amplifiers" 

On the TO3, I mean that quite seriously. I can’t remember the last time I saw anyone use a TO3 in a production design. Your idea of plentiful and cheap is likely different from mine. I don’t buy components off EBay unless I am finding something obsolete. You can find the odd TO-3 in stock at stocking distributors, but they are a rarity these days and legacy devices.


If you change the output stage, bias circuit, and the drive circuitry before the output stage, which means 2 stages of what is likely a 4-6 stage amplifier (and likely feedback to account for different bandwidths), then it is not the same amplifier any more. You can’t change 33-50% of an amplifier and say you are just comparing the output devices.  Yes end of story. Your claim that this allows you to simply compare output devices is not true.

Give it a rest sunshine it’s doable, and not as complicated as you make out, your full of it, I would estimate a days or less work for a good tech, with the components and schematic of the donor mosfet amp at hand.

Now lets get back onto the OP’s topic.

And it’s a different amplifier when done, and not indicative of a comparison of two sets of output devices .... sunshine. Yes, lets get back to the OPs topic which you side-tracked ....

georgehifi6,190 posts11-15-2019 2:13pmMany (me included) just don’t like Mosfet sound.
Listen to some older Threshold Pass amps that used bi-polars, you’ll change your mind.

Cheers George