JE990 Lives!

Here's one project I've been working on:

www.telusplanet.net/public/dulan/DaleJE990.zip

Note: I subbed in BC550C and BC560C transistors because that's what I had, and the outputs have been set for the B - C - E pinout, I used a 2SC3940 and 2SA1534. I have not done audio listening tests through it yet, but it does do a pretty good job at a square wave from a signal generator at unity gain. Enjoy!

Oh yes, it is in the same package and footprint as the API2520 so you could interchange them.

MAN!
You did it all! Gerbers and ddb file!!! THANK YOU!!!

cheers!
Fabio

This brings a smile to my face.... After giving up on this project a while ago (before I got the Jensen paper) I was hoping it might see the light of day.

:grin: :grin: :grin:

Go Dale

indeed rspx for fitting all that on a single sided brd! :thumb:

excellent stuff

trouble is, I can't look at any of it yet as I am on a foreign machine and can't load any of those file types.

what is APIPreamp.ddb ?

I may be able to find something to load the dxf file.

The .APT, .GBL, etc. are the gerber files. GCPREVUE or any other gerber viewer program should be able to load and print them. I don't have a PDF converter.

The DXF files are Autocad, though I haven't looked at them in that format. One is the schematic (which is the same as the real JE990 but with my subbed parts).

The DDB file is the native Protel project file, so anyone running Protel99SE or higher should be able to load the whole thing. That's the CAD system we run at work so I just use it.

can some one post jpegs and pdfs of this?

I've loaded the gerbers and the component names are missing. Can you send the overlay layer again?

cheers!
Fabio

I can view the .dwg file with Volo View Express.

Dale,
Have you tried Express PCB at www.expresspcb.com? It has a great, easy to use schematic drawing program and others can download it to view your schematics. It will also allow you to save your schematics as a bitmap file.

I guess I use Protel because that's the program I use to make a living at, so I work quickly using it. I was planning on getting a Adobe Acrobat, but I just haven't put out the cash for that yet.

Sorry about the component overlay but there's no room for designators. I'll try to maybe add the designators to another layer. That's what I usually do for my boards I do for production. If someone else can convert gerbers for now to something else that would be great - I only have a use for gerbers. The traces are a bit thin, 0.012". I use the presensitized photo process (MG chemicals) and ammonium persulphate etchant. I have no problems with this density - I've done as fine as 0.006" with my own process but that was a test only. Do you (as a group) prefer centre drill guide spots on the pads? I tend to like drilling without them as I find the centres tend to grab the bit.

Oh yea, you can see one of my boards in this brochure:
http://www.afsglobal.com/PDF/50-01009-1 Sparrow ECM Flyer.pdf That's a 6-layer board, all components on one side. It's an early revision; the newer one looks very similar - though a bit more dense. The missing parts are input and output chips that aren't used in many applications.

A couple of other projects I've been working on (and after I've tested and debugged them I'll post them) is a feedback-type SSM2018 compressor, a LA-4-like compressor with a special feedback circuit that allows a super-fast (for an opto) attack time if you want (you'll need two matched for speed optos), and a fairly quiet, fairly high-speed mic preamp using LT1115, LT1122, and LT1010 chips. All but the last one are single-sided boards, the last one is double sided. Any interest?

always interested! count me in!

:shock: look at that ECM board.... now that is density..

:guinness:

"CAN bus"
Eeek! Run away! Hide!

VERY Nice PCB there, Dale!

:green:
Charlie

I am interested.

Ok, I just got Acrobat so I'll put stuff up there tonight in that format. I think everyone can read that format.

Try this:
http://www.telusplanet.net/public/dulan/JE990.pdf

so, okay to roll on wiv just matching the input BC550's - or do any of the others need pickin n sortin too?

Thanks Dale!! :thumb:

Michael

Has anyone built this?

Seems like the files are down but I dug them out of my hard drive...have I missed something? The PDF files seemed to be just the copper layer and no overlay at all.

Opened up the gerber file though and took a look at the unmarked overlay. I decided to fill in the blanks tonight (designations after the AES paper schematic):

(sorry for the image size)
Looks like it need a little modification to become a real 990...

Looks like it need a little modification to become a real 990...

Click to expand...

Without a LM194 it will not going to be a 990.

Samuel