API 312 homemade

[sam system-d]

Hi everyone, it's been a while since my last post.
Actually, I was working on something everyone will say it's easy, but not that easy for a newbie (and other stuff, Bo Hansen DI, 1176 rev F).
Here is my version of the api 312 preamp, a mix from Fabio Bauman's work (replica312) and Jeff @ classicapi vp312.
So first, I ordered some parts at Jeff's store, gar2520 , input and output trannies.
Then I checked Fabio's etching files and schematic.
Well, I didn't get eerything, but most of it.
I didn't wanted to use the servo output, the line input , I wanted the DI, but onboard.

So comparating the 2 schematics, I follow Jeff's mainly, adding some features from Fabio, like the DI.
It feets in a 100mmx160mm, control board and main board. Lorlin 12 pos for the gain switch, relays for pad, polarity and DI.

I've just etched the two boards, I hope everything'll be ok for this first project kinda personnal.
If Jeff and Fabio don't mind, I'll post the self etching files (and if they work!!!).
I use Fabio's 312PSU, as I didn't check yet how to design a good PSU (I know, "HOW CAN YOU PRETEND DOING DIY WITHOUT KNOWING THIS???!!!" yes, I know, give me some time  ;D).

Here is a picture of the board :


I hope you'll like it, more to come during this week, the goal is to make them ready for saturday's recording session. Metal work will start on wenesday if everything goes right, the faceplate will be something as usual, simple, but efficient (if you ever saw my G9 project). Next one will not be self etched  but it will be a killer, as everyone has built it, I'm talking about the EZ1290 (And still got in mind the GSSL...)

 

[Meathands]

Cool, and thanks for sharing! Please let us know how it goes.

 

[hobiesound]

cool! did something similar sans the di and relay switching a while ago. Love the satisfaction you get when you just take a circuit study it and then make your own pcb for it serving your needs.

good luck finishing it!

greetings,

Thomas

 

[grantlack]

looks like a very sharp etch from here, i can't always claim the same  :.  care to comment on your etching process?

 

[sam system-d]

I usually work with Bungard board and KF material for chemicals and etching machines (sorry I don't know the words)
On this one, I use a cheap board from musikding, I have to say that they're really good.
1m45sec under UV lamps
30sec in hot revelator (nacl or something like this)
and checking the time in the FeCl3. Usually 10mins...
Print traces on transparent paper for inkjet, put a lot of black on it with higher resolution.
That's it

 

[sam system-d]

Work in progress...

 

[creal]

Cool mister,
super projet, j'ai justement besoin de faire 4 autres PreAmp API
Tiens au courant de la suite

@+
Cyril

 

[sam system-d]

Next step :
Drill the faceplate, built one doa, wire everything.
Here it is with the others units.


Still one DOA and the power supply to built, and rear plate to drill... Should be ok tomorrow night! I'll paint it next week probably.

@Creal :
4 preamp can fit in 1u without the jack for the DI :/ too bad for me.
I already ask Jeff if I was able to upload my files, but it's an "easy" project, not too much componants, and without the relay switching, it can be even easier.

 

[sam system-d]

So I was supposed to finish it for tomorrow. It's 2.30am, it's working. At this time, newbie mistakes are easy to make, but no damage at all. Channel 1 is working great, DI too. I have to wire channel 2. Ok, I still got a problem on the PSU, I should have 48v, I just got 40... I will fix it next week, I don't need 48v tomorrow.
Thanks again to this wonderful forum where I found almost every information that I needed to built this thing.
And YES, hobiesound you were right, I feel so good now

And few pictures (including all the process)

 

[sam system-d]

So if anyone need the etching files, just pm me.
Everything's working well on mine.

 

[creal]

Next step :
Drill the faceplate, built one doa, wire everything.
Here it is with the others units.


Still one DOA and the power supply to built, and rear plate to drill... Should be ok tomorrow night! I'll paint it next week probably.

@Creal :
4 preamp can fit in 1u without the jack for the DI :/ too bad for me.
I already ask Jeff if I was able to upload my files, but it's an "easy" project, not too much componants, and without the relay switching, it can be even easier.

Very nice job mister Sam
i like to had 4 pre to my 4 fabio's 312 and put them in a 3u
Thx
Cyril