F3 Builders Thread

[peppennino]

The information that I could find from Firstwatt on the F3 is below. Please note this is not the same as the dual mono power supply used on F1 or F2 and that was supplied in the latest F3 Group Buy. See post 120 of the F3 Clone Board Set Group Buy thread for the schematic of the boards in the group buy.

So, with your PCB, can I go for dual mono 2X36Vac? in your BOM schemathic there are 8x50V 15mF caps but secondaries are marked as 2X18Vac

 

[BRN]

I want to make sure that this is how to use the bipolar power supply using the 18v transformer to power the F3.

 

[Zen Mod]

just move TH1 to new-established GND

 

[BRN]

Is this what you mean?

 

[Zen Mod]

of course

 

[marconi118]

How does the F3 sound compared to the LUDef?

Yes i know the LuDEF is a PP buffer with Xformer gain stage and the F3 has the LU as gain stage, but both are dominated by the LU triode cell
it should be a fair comparison?!

 

[peppennino]

Play time...

 

[peppennino]

Another heavy weight amplifier

 

[davidjt]

Thanks for those - I was about to order 35V Silmics, but clearly they wouldn't fit!

 

[csample]

The BOM for the GB has the physical size and lead spacing for various components hopefully this makes parts selection easier.

 

[csample]

Looks good peppennino, I couldn't resist stuffing the output cap boards the day they came either!

 

[davidjt]

The BOM for the GB has the physical size and lead spacing for various components hopefully this makes parts selection easier.

Indeed. It would have been a stupid mistake - the boards are elsewhere and scarcity of components was about to lead me astray. Not to mention RTFM.

 

[andynor]

Maybe a futile question, but does anyone by any chance have some spare Luvotechs fit for an F3?

Vinz tipped me about Ali as a possible source, but unsure if reliable source for this kind of part?

Any pointers received with great appreciation.

Regards,
Andy

 

[wg45]

Maybe a futile question, but does anyone by any chance have some spare Luvotechs fit for an F3?


Yes, I have some of Papa's matched pairs. We ran a GB earlier this Summer-

Lovoltech 1014D GB

Please read through the posting and let me know what you would like by PM. Please note shipping to Europe has been running slooow and it is expensive.

 

[Vunce]

Hey Pepennino,
Cap boards look sweet stuffed with a bunch of Silmics! I’m right behind you
What do you Fellas think of this combo? (Not soldered yet)
Nichicon KG 10,000uF
Elna Silmic 1000uF x5
Polycarbonate Film 10uf

 

[Vunce]

Some F3 assembling progress.
Amp boards just need mosfets, Jfet and R5 installed. I can’t proceed further until I decide on a chassis. I could use a 4U 300mm case if I transplant the amp that currently resides inside…..
Vias for ‘U’ shaped test points are a nice touch Chas!

 

[peppennino]

Look niiiice!
For coupling caps I'll try Silmics for fullrange response and 1mF (2x500uF) MKPs (military surplus) for upper freqs on SLOBs (8" FR crossed @150Hz). Rear panel will have two pairs of terminations: with and without opt caps.

 

[peppennino]

Is a 350VA donut enough for a stereo build? Thanks

 

[Dennis Hui]

Assuming a decent 350VA transformer it'll be fine; I believe the first watts from that era used 300VAs from Plitron.

 

[BRN]

You guys are making me excited. I just just received the last of the parts I need for my amp. This included 30 Silmic caps. Now I need to tap my heat sinks and stuff the boards.