F6 Illustrated Build Guide

[Zen Mod]

change that for mica and goop , torque properly

 

[2 picoDumbs]

Sounds like not good enough, difference is closer to 20C!

Here's a picture... EDIT: and a slightly better one.

I have a whole heap of those and I threw them in the bin.

 

[silasmellor]

Alright, i guess those aren't real keratherms. I have some keratherms on the way from the store, so i might try those out first and then switch to mica and goop if they don't deliver. Thanks Zen and Pico.

 

[2 picoDumbs]

From the results Euvl posted keratherm performed even better than mica and goop.
I haven't personally done that comparison (mica vs keratherm) but I wouldn't doubt it. Keratherm really is that good.

 

[Zen Mod]

Keratherm will deliver

 

[ilikeit]

Probably not related to topic question, but related to my F6 build.
Q: Best way to desolder transformer from PCB with minimal damage?

 

[2 picoDumbs]

solder wick

 

[poseidonsvoice]

And/or chip quik. A little expensive but it works fantastic on hard to remove SMD components and I’ve used it for through hole stuff too. Check YouTube for ideas. EEV blog has some great videos.

YouTube

Alternatively, you can bridge all the pins together with a remaining resistor lead and heat all the pins at the same time in rapid fire mode while lifting the transformer.

Best,
Anand.

 

[costl]

Update to #918-919: Replaced Z1, Z2 with 6.8V Zeners, and R7 and R8 with 3.3K. Biased up easily, offset perfect. Sounds lovely.

 

[ColinA123]

Well done.

 

[PDL]

Has anyone tried Berquist Sil-Pads?

Are they comparable to keratherm?

 

[2 picoDumbs]

No idea. Possibly good. I think I might have some white berquist pads laying around maybe I'll get around to doing a comparison if I find them.
The thing is if you buy them and they are just ok later on you're probably going to want to buy the keratherm pads in which case you have wasted money like I did.
May as well get the best the first time around.

 

[needtubes]

Has anyone tried Berquist Sil-Pads?

Are they comparable to keratherm?

To my non-engineer's eye, Keratherm appears much better on the datasheets. I have not used them, though. I am currently running Sil-pad 900S on one of my amps and can verify that I see case temperatures which are at least 30C hotter than the heatsink temperatures. This has me wary of pushing the dissipation higher, which was my original intent. There is, of course, a Sil-pad which offers better performance than the 900S I am using, but I've only found it available in large sheets, which are expensive and must be cut to size. Plus, the datasheet still suggests worse performance than Keratherm...

 

[ilikeit]

Can i use following zeners 1N4733A, desc: 5.1V 1W Zener Fairchild Zener Diodes
Link to mouser: 1N4733A ON Semiconductor / Fairchild | Mouser Europe
Do i need to match them?

I measure voltage after zener, and DiyAudioStore zeners give me around 4.6V, but 1N4733A give me 7.2, so hmmm

 

[Zen Mod]

exact schematic ?

several variations , so important to know for proper answer

 

[ilikeit]

I'am use 9V battery, and measure voltage after zener, i don't care maybe need to add load resistor after zener as multimeter can't be enough mA load. I'am using DiyAudioStore PCB's.

 

[Zen Mod]

you need series resistor between zener and battery , to limit current

say 1k

if you connected zener direct to battery , say sayonara to zener

regaring pcb - I don't care which ones , I was asking for schematic ....... mosfet or JFet outputs , which resistor in series with zener ?

 

[ilikeit]

Schematic: http://www.diyaudio.com/forums/gallery/data/500/F6_DIY_SCH.gif
Mosfets outputs

 

[Zen Mod]

any zeners , what's important - new ones ..... exact 5V1 voltage isn't important

you'll anyway set what's needed with trimpots

R7 and R8 - decrease to 3K3

 

[ColinA123]

Like this.