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PCBs for Aleph 2, Aleph 3, Aleph 4 and Aleph 5 amplifiers

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Hello,


I used separate PCBs for each channel and without silkscreen overlay, because they were the first prototypes for the Balanced Line Stage preamplifier.

Also, the all PCBs that are located on my homepage :
( http://web.vip.hr/pcb-design.vip ) are made of FR-4 fiberglass material with Cu-50 mikron + Pb track overlay (tinplated),
laser drilled, with two sided blue soldermask (instead of green), and with white component overlay.




Regards,
Kristijan Kljucaric
 
hi,

Thank you for clearing that out for me.
I was a little confused about the blue soldermask on your PCBs.
I never saw the blue ones before.


When the power supplies for the preamplifiers will be available, and why they are not located on the same PCB with the main circuit ?
 
Hello,


The power supply PCBs will be available in about couple of weeks.

The power supply is not located on the preamplifier PCB.
The reason that is designed that way, is that the power supply can be builted in the separate enclosure, if desired.
Also, there is less chance for the noise pick-up, if the power supply would be moved away from the main circuit.



Regards,
Kristijan Kljucaric
 
PCB design process

Hi,

I'm very impressed by your PCB's. What do you do for a living... EE, Board designer?

Well, since you seem to be such a talent in the field of PCB manufacturing, could you please (pretty please with sugar on top) tell us (less talented) how you do it? Are you doing it all in a design program, and then send a file of some format to a board manufacturer? Or do you design the boards in a program, printing it, etching boards at home and test them out in some mysterious way and let the boards evolv iteratively before you get them manufactured? Or do you silk-screen your board at home during some mysterious ritual?

I do want to become as good as you in making boards, but I have no clue on how to do so.

Internet is such a fantastic place for learning new stuff.

Best regards,
//magnus
 
By the way... Laser drilled holes, tinned, and silk-screened... Phew... Beats my boards by miles.

I usually use that "Press 'n Peel" paper and a hot iron to manufacture my boards. Then I have to look it all over a thousend times before I etch it. After that I have two full nights of drilling the darn things on my girlfriend's desk, since mine is overloaded by all crap I collect.

You really kick ***, compared to me!

//magnus
 
Hello Swede,

At first, I design all the PCBs on the paper, acording to the schematics.
After that I make (by photo methode) and test the prototype PCB.
At the end, the final finished layout is redraw in the PROTEL designing program.
All of the mentioned steps are very time consuming, and they are really nervbraking if you would like to have good PCB layout.
After the design is finished in the PROTEL, almost all the neccesary work is done by the proffesional machines for making the PCBs.

You mentioned that you made the PCBs with the "Press 'n Peel" paper and a hot iron, and that then you have to look it all over a thousend times before you etch it.
Why you don't try the photo methode ?
It is also easy, and the whole work can be done in a reasonable time, but with the much precise and better result than the method you mentioned.

Also, it is not the problem to make the PCBs when you have everything finished and prepared, it takes far more nervs and effort to properly design them from the schematics.



Best regards,
Kristijan Kljucaric
 
Photo method

Hi,

Thanks for your response!

The reason for me using Press'n Peel, is that I never really got the grip and touch on how to do it using UV light. I always seem to overexpose the photoresist and when I develop larger boards, it usually develops different from side to side on the boards. I might have to practise some more or find someone nearby that knows how to do it.

Or, do you have a good description on how to do it? I would really like to do it the "right" way.

Best regards,
//magnus
 
Hello Swede,

If you always get the bad results with the photo-metode, than you do something wrong.

You should always place the glass over the board and the exposure film, to ensure that there is no any gaps between the PBC and the film.

For the best results, use the photoploter film.

Also it is possible to have good results even without the photoploter film.
You can print the layout on the normal paper with the ink-jet printer, use high resolution, or print several lower over the another, and then spray the PCB and the paper with the Pausklar spray, remove all the bubbles that will appear, and than exposure to the UV.
This way there is no need for the glass over the paper, because the paper will be sticked to the PCB by the Pausklar spray.

If you don't have the UV lamp, you can use the sunlight.
If use the exposure by sunlight, the time of the exposure should be around 20 seccond for the photoploter film and around 35
seccond for the paper.

Also, you should check the NaOH solution, use the 7-10 g
of NaOH on the 1 litter of water, depending of the manufacturer of the photoresist.


Best regards,
Kristijan Kljucaric
 
I have used a simular metode as Kristijan-k with good result, but instead of using normal paper. I'm using transparent tracing paper. There are several brands, the type i'm using is from Schoellershammer and called Glama MicroDraft Hochtransparent. I print my layout on a good laser printer (HP 4plus) and use the print directly, No pausklar!. Allways print so that the printed side is in contact with the photoresin on the board (mirror the buttomlayer).
In the olddays I sprayed the photoresin (Positiv20 from Kontakt Chemie) myself, but i'm starting getting lazy and now I am using ready sprayed pcbboards from Bungaard now.
This metode works very well for normal circuits boards. but if you want to make a more detailled board, you should get a film made by an offsetprinting company.

Claus
 
kristijan-k
it's hard to tell from the picture, what kind of gauge wire could you solder in the two +/- power and output connection. Also, I noticed that you have two ground connections on the board. Are you running separeate grounds for input and feedback to the star point? Is everything tested to be hum free?
 
Hello grataku,

On the PCBs, for the all wire terminals are drilled holes of 1.35 mm in diameter.
They are 1.35 mm, because that the standard terminal pins can be used, if desired.
Also, the all pads are big enough that the holes can be bigger, if the larger gaugue wires would be used and without terminal pins.
But, I don't see any justified reason why the terminal pins should not be used.
There are two grounds on the PCBs, and one of them can be used for grounding the unused input to the ground, in case of using source/preamp that don't have balanced outputs.


Best regards,
Kristijan Kljucaric
 
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