My F4 Build

[Einric]

Would 20W per device be too much for the JFET's?
What is the safety margin for the 170's & 74's?
I did get some TO-92 heatsinks installed.

 

[Zen Mod]

yes , 20W per T092 case is too much

 

[Einric]

Nice....I should be more specific. 🙂
Would 20W per output device put too much strain on the input JFET's?

 

[Zen Mod]

nope

irrelevant

 

[Einric]

All the parts are on their way.
I should have more progress by later this week.
This is exciting!!!

 

[Einric]

Fans Are Here

My parts are rolling in, I am just waiting on the Toroid from Antek, It should be here in a few hours.
In the meantime here is a picture of the heatsink & my new fans.

 

[6L6]

Nice!

 

[Einric]

P/S Layout

Here is my Power Supply layout.
My first thought was to tip the Toroid up on it's side but it's .25" too big for that.
All of the caps are CD SLPX 25V 18kuF.
I went big with a 400VA Toroid.

 

[6L6]

Looks good!

 

[Einric]

Every now and then I see articles about certain speakers that say they require an amp that can drive "difficult loads" or the speaker that is a "difficult load".
Now, I don't know whether or not they are talking about phase or low ohm's or what but......
How does the F4 handle these "difficulties"?

More progress & photos to follow later tonight.

 

[6L6]

How does the F4 handle these "difficulties"?

It grips them by the face and drags them to the lower reaches of Hades.

 

[buzzforb]

Listen carefully and you can hear the F4 laughing😀 Now build another and add one of these.
http://www.diyaudio.com/forums/attachments/pass-labs/353307d1370698639-ba-3-preamp-image.jpg

 

[Bigun]

It grips them by the face and drags them to the lower reaches of Hades.

You should be in marketing - I wanna build one already !

 

[6L6]

Build it. It is my favorite of the 3 Pass amps I have built. (I have yet to hear the F6, but that will be soon...)

 

[Bigun]

It's lotsa heat for the summer but good for the winter - sorry I didn't try a search yet for any threads/links where I can get some idea of how people perceive the sound when used at low bias like Class AB - did you get a chance to try listening when you had it biassed low ?

 

[6L6]

Look at my build guide and see the distortions at lower bias levels...

 

[Bigun]

I took a look - great guide by the way. I saw the scope plots but I can't translate it into sound. To be honest, it looked pretty good even at low bias.

 

[Einric]

Cap Bank

I have completed my Capacitor Bank.
It uses 18kuF CDE SLPX 25V caps, all other parts are stock.
It looks a bit wonky but I think it's RADD MAN .

 

[6L6]

Looks awesome!

Tie your inner (GND) tracks together.

 

[Einric]

Yeah, I'm gonna do that once it's in the chassis and I know which direction things need to go.
Table Saw's are really handy!!!
I cut those out in the garage and kerfed the copper out for my voids on both sides.