Firstwatt F1J

[adason]

Noted

 

[adason]

Just measured... When power supply is 10V, Uds is 1.9 V. At 15 V, Uds is ~2.1V. All good.
Current seems pretty stable.

 

[wg45]

Thanks for sharing, Adason.

I'm glad to hear the trial with the LU1014D in the F1J worked and sounded good.

 

[xrk971]

Nice work Adason! You might participate in the GB just because Wg45 ordered like 1000 of these TO-247 IMS adapter PCBs for the LD1014D or LU1014D.

They really do make using the LU’s easier. I use the crimp sockets from a Molex MiniFit Jr connector to slip over those big header pins.

 

[peppennino]

Very interesting, as I love fullranges...

 

[adason]

Nice work Adason! You might participate in the GB just because Wg45 ordered like 1000 of these TO-247 IMS adapter PCBs for the LD1014D or LU1014D.



They really do make using the LU’s easier. I use the crimp sockets from a Molex MiniFit Jr connector to slip over those big header pins.

I know about the GB, its just that getting two jfets and four adapters did not make much sense to me
one needs four of each for F1J
plus it looks too professional 🙂

 

[csample]

That's really cool adason! Thanks for sharing!

 

[adason]

Thanks for the boards Chas!

 

[adason]

did quick test
at moderate level, 0.92Vpp, ~0.125watt, with speakers on, assuming ~8 ohm
distortion 0.015%
second and third harmonic only, nothing else

 

[peppennino]

Yup, time to take the Gerbers again 😀

 

[wg45]

Maybe Chas could update his F1J boards for the LU1014D. That might be interesting.

 

[peppennino]

+1

 

[wg45]

F1J Getting closer....

 

[marconi118]

can you post a schema of F1J with LU1014 ?

 

[vitalica]

I finished another F1J SS120R100A amplifier, and I would like to use Toshiba 2sj 618 transistors instead of Q3-Q4 IRF9240, and use 2sk3497 instead of Q7. Should I make any changes to the resistor values for this case?
And one more question. If the preamplifier has no DC voltage at the output, can capacitor C1-C2 (10MkF) be removed?
Thanks a lot !

 

[Zen Mod]

no change needed, regarding resistors, if you want to use those other mosfets

caps at input are must - whatever you have for preamp, you don't want to fry it with amp (having 7V at input nodes)

I'm not even thinking will it work or not

 

[vitalica]

I understand and thank you very much for the answer, ZenMod
Will Iron Pumpkin drive this F1J amplifier?

 

[Zen Mod]

of course it will

even F4 is happy, when driven with Iron Pumpkin

 

[vitalica]

For that I have to set Iron Pumkin to max 8dB, right?😉

 

[Zen Mod]

yup

but you can give me few more details .......... source, etc

well, I'll even look at F1 data, to complete calculus