A guide to building the Pass F4 amplifier

[myleftear]

571-15463065 1546306-5 TE Connectivity Barrier Terminal Blocks .374 DOUBLE ROW 5P w/ binding screws

1546306-5 TE Connectivity / AMP | Mouser

Great, thank you!

 

[myleftear]

Zen Mod I needed information, to weaken the amplifier (I need only 7-8W) what should I change compared to the original scheme?
- remove two pair of output device?
-descrease the power supply voltage?
-change the value of bias setting?
-change the value of some component?
Precise that I currently have an E88CC SRPP Preamp with a gain of about 28-29dB and a pair of heatsinks of the dimensions of 35x125x250 mm.
Thank you in advance

Hello sergiog
(sorry my autocorrection put it wrong)
I just read this post of yours. Having the same issue, I wanted to ask if you followed this path and did build a "2/3F4"?
How di it work?
How did you do it?

thank you!
david

 

[6L6]

You’ll never get more power than the voltage your preamp can give to the F4...

 

[myleftear]

You’ll never get more power than the voltage your preamp can give to the F4...

Ahh same trap again!
I should come to terms with f4‘d concept and just build one. [emoji4]

 

[6L6]

Yes.

 

[myleftear]

BUILD!

Ahh same trap again!
I should come to terms with f4‘d concept and just build one. [emoji4]

Yes.

Everything but the chassis is here. (probably 1 or 2 parts glitches and Salas' B1 waiting for me)
...
At the moment, I'm trying to work out (like, calculate 😕) the heat-sink-requirements. Looking for power-dissipation per transistor etc etc...

6L6, I read that you use cardas quad eutectic. Do you use their Rosin Flux Paste too? Because I do, and it's quite messy...

 

[6L6]

I like the Cardas Quad. I have not used their flux.

Heatsink requirement is easy - 4U deluxe chassis. 😀

 

[myleftear]

I like the Cardas Quad. I have not used their flux.

Heatsink requirement is easy - 4U deluxe chassis. 😀

I know it‘s easy. [emoji4]
I would still like to (try to) calculate...[emoji851]

 

[6L6]

Nelson’s rule of thumb is 10x15cm of heatsink per output device.

 

[Blk Dynamite]

I like the Cardas Quad. I have not used their flux.

Heatsink requirement is easy - 4U deluxe chassis. 😀

I've used their flux and while nice I don't think its needed for most applications. On top of that its a pain to clean the excess which can be a lot even when using a small dab. Been using the Cardas solder though for a few years and its great. I use it and along with kester solder

 

[jervill]

Hello sergiog
(sorry my autocorrection put it wrong)
I just read this post of yours. Having the same issue, I wanted to ask if you followed this path and did build a "2/3F4"?
How di it work?
How did you do it?

thank you!
david

For this idea, why not a Mofo build with lower voltage? (I don't know what low power Mofo sounds or measures btw, just the first thing to jump in to my head.)

To get 7-8w max out of my F4, I adjusted B+, the primary (5k to 2.5k) and secondary connection (4k to 16k) of my 2a3 SE amp and drove it with that.

 

[myleftear]

For this idea, why not a Mofo build with lower voltage? (I don't know what low power Mofo sounds or measures btw, just the first thing to jump in to my head.)

To get 7-8w max out of my F4, I adjusted B+, the primary (5k to 2.5k) and secondary connection (4k to 16k) of my 2a3 SE amp and drove it with that.

jervill
Nothing. Nothing speaks against building a Mofo. Quite the opposite. But only _after_ F4 🙂

🙂

 

[vdi_nenna]

Nothing. Nothing speaks against building a Mofo. Quite the opposite. But only _after_ F4

I'm close to finishing a 4th power follower type amp.
The F4 is special. The MoFo is amazing for it's low parts count and what it can do sonically.

 

[6L6]

The F4 is special. The MoFo is amazing for it's low parts count and what it can do sonically.

Perfectly said.

 

[myleftear]

will do, will do 🙂
(Can't say anything abound MoFo except that Nelson's Introduction was... "drool-inducing")
PCB is here since ages.
First/next have to come along with SK170B

 

[myleftear]

chatter

will do, will do 🙂

preemptive bliss
😎

 

[Kajakfisker]

New here, but just Got myself a F4 amplifire and already love it, but What preamplifire will be the best for this - valve solid state or What ? Home build will be alright to... sorry if it is the wrong place to post

 

[2 picoDumbs]

That will depend on your personal preferences and also how much voltage gain you need.

You could hookup a BA2 frontend as a preamp.
That would be pretty nice.
There is also BA3 too.

 

[6L6]

As mentioned, either of the Burning Amp front-ends would be great preamps for the F4.

Impasse by Stuart Yaniger

Pumpkin by Zen Mod

Aikido by John Broskie (TubeCad.com)

 

[Spica]

I am getting a handle on most of the parts to order, except the LEDs.
There are hundreds listed on Digikey. My search didn't turn up
any parameters to look for. If someone could list the important specs
(or part number) I would be grateful. Blue would be my preference.