F5 power amplifier

[seventenths]

Dougie,
91 bucks for the PSU parts ? I got my transformers on the CHEAP and I'll still have considerably more money into it.
What version?


Cheers,
7/10

 

[Dougie085]

Well thats for one channel and doesn't include the switch, transformer, fuse and stuff. Do you think you could make up a BOM of yours? I used this schematic.

An externally hosted image should be here but it was not working when we last tested it.

I tired but I'm not the greatest at reading schematics And like I said I wasn't sure what values the zeeners should be and what not and what the rectifiers should be.

 

[seventenths]

Ahhhh,
Now that makes more sense.

I'm building the same supply, but with 2, 20V/200Va single output transformers per channel. I'll be trying to wind the inductors tonight

Ordering 12, 30000uF caps and the requisite humongous heatsinks and the MOSFETs soon.


stoked
7/10

 

[Dougie085]

I got heatsinks a while back. I'll be using 2 of these per channel. They will be monoblocks as I mentioned before.

I'll have to make up a BOM and post it before I order stuff cause I know I probably messed something up.

Where are you getting the caps from? And how much?

 

[Zen Mod]

boyz and girlz ........ it's almost funny ;

it's n'th time that I'm - from Serbia - writing again - Steve , at Apex Jr. is a man to ask for caps ....... sometimes even for xformers and 'sinks ;

 

[Dougie085]

I shot him an email. See what he has. It's ok to use caps larger the 30k uf in this PSU right?

 

[Zen Mod]

I shot him an email. See what he has. It's ok to use caps larger the 30k uf in this PSU right?

as you boyz , from country wearing flag beneath your nick , use to say ........ there is no substitute for cubic inches .



put 'em as much you have .......... ribs , mF , VA .........

that's A class , not dreky AA one .



edit :

did you checked on his site ; maybe you can see something ..... without waiting for reply

 

[Dougie085]

Yeah I looked he didn't have anything listed that would work.

 

[SCD]

Heatsinks

Hello Dougie:
I am no expert in heat dissipation but I am thinking you are grossly undersizing your heat sinks.
A 6x6 heat sink is pretty small for the wattage this amp is running.
You may need to rethink your approach.

 

[Dougie085]

Nelson said 2 of them per channel would be adequate. In the length they are they do .75c/w or better. Also isn't this amp quite a bit more efficient then other Class A's?

 

[Zen Mod]

Yeah I looked he didn't have anything listed that would work.

http://tiny.pl/ngd2

look for 12,000Mfd/50V ; 15,000Mfd/63V

if that isn't a deal , I dunno what is ......

 

[Dougie085]

MFD isn't the same as uF is it?

 

[Zen Mod]

MFD isn't the same as uF is it?

yup ,it is - most the time ;



you can learn much just starring on pics ( and sometime lookin' what's written bellow )

 

[Dougie085]

Then I'd have to use....12 per board instead of 6. If I used the 15,000mfd hmm thats a lot of caps.

 

[Dennis Hui]

Dougie,

Maybe you should consider an unregulated PS. The
ZV5 needs one but the F5 doesn't. ("Ordinary
unregulated supplies will work fine....") This will
simplify things quite a bit.

The caps that Zen Mod mentioned are a good deal
and definitely worth considering.

Also, what transformers are you planning to use?

Dennis

 

[Rodeodave]

As far as I remember it has not been mentioned in this thread that, besides the package and the power dissipation:

2SK370 is the same as a 2SK170
2SJ108 is the same as a 2SJ74



Experienced ones,

needless to say, already knew.

New it was to me.

 

[Dougie085]

Well I have a Aleph PSU board that I got from chipamp.com. But a regulated PSU would be nice and I don't think it will be that hard to build I just need to remember all the schematic symbols. I'll probably just use something like a 300VA 18VAC transformer. Avel or Plitron depending on how much I decide to spend.

 

[Dougie085]

Thanks Rodeodave, I was trying to find an alternative to the 2SJ108 as mouser didn't have it.

 

[Variac]

Wouldn't this F4 power supply work well?
My impression is that Nelson uses pretty much the same supplies with the F series unless there is a reason not to..

And if it's good enough for Nelson..

http://www.firstwatt.com/downloads/f4_om.pdf

There is a power supply schematic towards the end; Page 15

Mark

 

[Dennis Hui]

Well I have a Aleph PSU board that I got from chipamp.com. But a regulated PSU would be nice and I don't think it will be that hard to build I just need to remember all the schematic symbols. I'll probably just use something like a 300VA 18VAC transformer. Avel or Plitron depending on how much I decide to spend.

Hi Dougie,

Just remember that if you do go with the ZV5 regulated supply
that you will need a transformer with a higher secondary
voltage.

Good luck.

Dennis