My DIY 4-channel API 312 (w/ pics)

Nate Dort · Post by **Nate Dort** » Fri Jan 11, 2008 4:41 pm

I posted this over at groupdiy also.

I finished up my 4-channel 312 build a few days ago. Everything works except the VU buffer circuit, as I need some germanium diodes for the bridges and shielded signal wire from the main boards. I used Fabio's (from groupdiy) PCB design. Channels A & B are 2520BCs, and C & D are Melcors, both DIY. All the boards were etched by me at home. Cinemags in and out on all four.

I screwed up and ordered relays with the wrong footprint, which explains the yellow jumper wires. I probably should have sucked it up and bought new ones. I also wish I would have ordered a deeper chassis, as it was a tight fit. Oh well. Front panel was laid out in Illustrator and engraved by FPE. No in-fill. I sent them my Par-Metal front panel, but the USPS lost it. I had to use their material.

Oh, and Dort is my last name, which explains the symbol on the front. The logo is based on the old Dort Motor Cars logo from the turn of the 20th century.

shedshrine · Post by **shedshrine** » Fri Jan 11, 2008 5:31 pm

Man, where is the little bowing man icon thingy. THat's gorgeous.

Hate to say it, but Ive still got my mxl mod boards in the bubblewrap manilla envelope they came in.

ps- my first car was a dodge dort.

digitaldrummer · Post by **digitaldrummer** » Fri Jan 11, 2008 7:41 pm

very nice!

blunderfonics · Post by **blunderfonics** » Fri Jan 11, 2008 8:12 pm

That looks fantastic. I'm curious how you got your Illustrator layout into Front Panel Express. As far as I know, Illustrator does not export HPGL. Any tips would be appreciated.

Thanks!

Nate Dort · Post by **Nate Dort** » Fri Jan 11, 2008 8:22 pm

There was a post over at groupdiy about converting illustrator to eps and then to hpgl with some other 3rd party software. I can't remember exactly how I did it, but it had to do with converting the text to paths, and then filling in with concentric paths. I have it bookmarked on my work computer. I'll post it Monday.

FiveFish · Post by **FiveFish** » Fri Jan 11, 2008 9:01 pm

Great job! Nice!

brianroth · Post by **brianroth** » Sat Jan 12, 2008 1:08 am

Nice work! I guess the close proximity of the power transformer to the circuit card(s) didn't cause any hum problems?

Bri

inverseroom · Post by **inverseroom** » Sat Jan 12, 2008 5:50 am

SWEET

Smitty · Post by **Smitty** » Sat Jan 12, 2008 6:56 am

*applause*

roscoenyc · Post by **roscoenyc** » Sat Jan 12, 2008 7:25 am

Bravo indeed!

Jed · Post by **Jed** » Sat Jan 12, 2008 7:33 am

Man, that is tight in there.

That's the kind of thing that makes wiring it up an even bigger PITA than it already is.

GORGEOUS front panel.

Seconding Brian's question, if you have any hum issues you might be able to solve them by switching to a torroid. Or moving the power supply outside of the case.

How does it SOUND?!!

Nate Dort · Post by **Nate Dort** » Sat Jan 12, 2008 10:18 am

There's no hum at all, which surprised the hell out of me. I took a chance with a power transformer I already had laying around, and it works fine. My G9 (2-channel tube pre) has much more hum, especially on the channel closest to the toroids.

Jed · Post by **Jed** » Sat Jan 12, 2008 10:25 am

Nice! That's some good luck!

BTW - I especially love "Not On."

Nate Dort · Post by **Nate Dort** » Sat Jan 12, 2008 10:34 am

Jed wrote:How does it SOUND?!!

I took it over to my neighbor's house to try it out with his earthworks mics as overheads on his drum kit. Sounded fantastic. I haven't heard cymbals sound that good in a long time.

I screwed around with the acoustic guitar and found some subtle differences between the 2520 and the Melcor 1731. The 2520 seems more punchy in the low mids. The 1731 is smoother, with a slower attack. They're both useful in their own way though. I've got enough parts and boards etched to build two more of each opamp, so I can swap if need be.

I think on my next mouser order, I'll bite the bullet and get the correct relays.

Nate Dort · Post by **Nate Dort** » Mon Jan 14, 2008 8:44 am

blunderfonics wrote:That looks fantastic. I'm curious how you got your Illustrator layout into Front Panel Express. As far as I know, Illustrator does not export HPGL. Any tips would be appreciated.

Thanks!

Here's that thread I was talking about:

http://www.prodigy-pro.com/forum/viewtopic.php?t=18427

See Samuel Groner's post about halfway down.

Message Board

My DIY 4-channel API 312 (w/ pics)

My DIY 4-channel API 312 (w/ pics)

Who is online