F5 power amplifier

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Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
I think that Juma ,even if technologically completely right , somewhat overreacted .......

anyway - I was attacked numerous times in net correspondence in last several years ...
but - God forbid that someone here (at DiyA) attacked me every time when I wrote something goofy ........... lazy bstrdz didn't even corrected me every time ........

:rofl:

loosen up boyz ....... that's just electronic , nothing more .....
 
Variac

Variac

diyAudio Editor
Joined 2001
BurningAmp.org
Paid Member
Juma, Yes if someone posts information that is wrong it should be corrected, but your critical attitude was excessive in my opinion and not how we do things on these forums. It is not at all difficult to correct a mistake without insulting someone. There are many examples of this on DIY Audio, because that is generally how we operate. Some prefer a more aggressive approach and there are other places for them.

You have apologized if you offended anyone, and clearly you have offended various members, so let's say that you have apologized and move on. The important thing I assume is that YOU have learned also. As you said, learning more is the point around here.

:captain:
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
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G

gaborbela

Member
Joined 2005
EUVL said:
I just checked at Mouser.

FQA12P20 is US$0.68 at quantities 250+.
FQA19N20C is US$0.57 @ 250+.

Anyone interested in organising a group buy + matching ?

We really need some volunteer in the US. With 30% import tax, shipment cost, etc., it just does not make sense to get them sent to Europe and then distribute to the rest of the world. Otherwise I would have been quite happy to do so.

Failing that, I shall probably order from Fairchild Direct. Quite a bit more expensive .

HI to Everybody

Any one has 2 extra matched FQA12P20 & FQA19N20C . I have a need for them very badly .
The rest of the jets , transistors , PCB I have .I just need two matched pair power mosfet to finish my amp .

Thanks to all

Greetings
Click to expand...
 
stein2

stein2

Member
Joined 2007
Don't want to spoil yer having fun...

I think these are the first DIY pcbs from Serbia. Should be heatsinked and started in a few days, as soon as I sort the transformer...
An externally hosted image should be here but it was not working when we last tested it.
and a detail at input...
An externally hosted image should be here but it was not working when we last tested it.


(click on the link should open the images) The PCB design was done by DIYAF member, Borko KA, thanks to Papa.

I expect Zen Mod to do something with that annoying rolling smiley and say something inappropriate...
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
stein2 said:
Don't want to spoil yer having fun...

I think these are the first DIY pcbs from Serbia. Should be heatsinked and started in a few days, as soon as I sort the transformer...
An externally hosted image should be here but it was not working when we last tested it.
and a detail at input...
An externally hosted image should be here but it was not working when we last tested it.


(click on the link should open the images) The PCB design was done by DIYAF member, Borko KA, thanks to Papa.
Click to expand...


:rofl:

(btw. - it's certainly better when input jfets are kissing each other ....)
 
elviukai

elviukai

Member
Joined 2003
highend.projektas.lt/
Hi there, its 3rd time i read this thread tired already. I am in inspiration of building F5 to try them. I want version with balanced version or X supersymetry. mainly because its almost 4 years I do not have any single ended cable :D . joke to joke but.. I see two balanced versions.does anybody tried theese and does anybody tried pump up the power (add more outpur devices.I think J-fets can drive more than 2devices) if anybody have spare pcb I would gladly buy them. :)
 
J

jameshillj

Member
Joined 2005
/Supply bridges

Stein,
Suggest you replace those block bridges with fast shottky diodes like the Fairchild 'stealth' ((ISL9R...), the 8ETH03, the Cree CSD... - (no Trr at all = no current spike), etc.
- all are TO220 size, so could easily fit on those "magic" h/sinks.
The improvement is quite significant.

Upgrading those WW power resistors in the C-R-C may be worth doing, too.

Hope the start-up (Variac?) goes well.
 
stein2

stein2

Member
Joined 2007
I know all this my dear friend, and I would be delighted to replace the aforementioned parts with whatever you send me :spin:

Getting something other than this requires ordering parts in advance at least a month earlier and as I'm in the process of looking for the right amp for my ESLs it is not critical. I even used the not recommended IR's IRFP9240 for starters because if I ordered them in time, I'd still have two weeks ahead of me for doin' nuthin'... As Choky, that is ZenMod, repeated many times, this is Serbia... (still far much better than in Africa) :cool:

Cheers mate!

Robert Stein
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
stein2 said:
I know all this my dear friend, and I would be delighted to replace the aforementioned parts with whatever you send me :spin:

Getting something other than this requires ordering parts in advance at least a month earlier and as I'm in the process of looking for the right amp for my ESLs it is not critical. I even used the not recommended IR's IRFP9240 for starters because if I ordered them in time, I'd still have two weeks ahead of me for doin' nuthin'... As Choky, that is ZenMod, repeated many times, this is Serbia... (still far much better than in Africa) :cool:

Cheers mate!

Robert Stein
Click to expand...


regarding parts ....

for some - you just forgot that we discussed some other solutions (diodes ) ;

power resistors in CRC filter - it's certainly better if they have some own inductivity ....... so - unless you use real chokes , you can't find better ones than you already have
 
Nelson Pass

Nelson Pass

The one and only
Joined 2001
Paid Member
elviukai said:
I want version with balanced version or X supersymetry. mainly because its almost 4 years I do not have any single ended cable :D . joke to joke but.. I see two balanced versions.does anybody tried theese and does anybody tried pump up the power (add more outpur devices.I think J-fets can drive more than 2devices)
Click to expand...

Two of my F6 prototypes correspond to this. Both have 2sk289 and 2sj109 input stages
and drive 4 parallel pairs of outputs in Common Source mode. The difference is that
one of them has inverting inputs and functions as an X amp and the other uses balanced
"current feedback" like the F5.

They both work fine, delivering about 100 watts into 8 ohms, but the dissipation is a bit
high for the First Watt chassis/power supply, and the performance is not so great when
you leave Class A.

I haven't yet decided what it is that I'll release on that - perhaps something else
altogether.

:cool:
 
elviukai

elviukai

Member
Joined 2003
highend.projektas.lt/
Thank you Nelson, I still did not started F5 , but all parts are here already. I have some feeling (the same when mooved from aleph 5 to x100) that f5 will bring me more hi-fi sound(that means less warm and more resolution) which I like. I am sure that all/ half) Pass beauty will be here.

I have now new speakers (aluminium enclosures,ceramic and beryllium drivers. 97db/2.83v) and I am feeling that something wrong with amplifiers I have :) so time to try something new.

I will sleep with open eyes waitng for f6, however I will try to not spoilding sound play arround f5 to pump up power.

thanks again

R
 
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