Thursday, September 24, 2009

THE SUMINATOR



It's finished! Not only that, but it sounds absolutely transparent! Here's the scoop:

The Suminator is an 8x2 balanced passive summing buss. It essentially takes 4 stereo inputs and sums them into 1 stereo output. All input level and pan controls are done in the DAW, as there are no controls on the unit. The Suminator is totally passive (meaning it has no built in summing amplifier). Gain makeup is necessary due to the nature of the beast, so in order to use the Suminator, one would need to connect its outputs to a stereo preamp for the necessary makeup gain to get the signal back up to line level (-4dBu). Most stereo mic preamps just sit around collecting dust when it comes time to Mix. The Suminator puts your unused mic preamps back to work during Mix time. This need for a preamp is actually a blessing in disguise. The Engineer now has the ability to mix and match any preamps at his disposal to find a tone he likes for the Mix. Another great thing is the fact that its far less expensive to make a summing box without a summing amplifier. Most summing boxes are active and their high cost reflects that.


The Nuts and Bolts:
The Suminator is loaded with NOS military-grade Allen Bradley carbon comp resistors.  The resistors are sorted and matched to within 1% tolerance for the Suminator. The XLR connectors used are Neutrik with silver plated contacts. The internal wires are twisted pairs of silver plated wire terminated with silver solder.



Output loss is about -16dB, which is easy enough for any preamp to handle.
It likes to see a load of about 300 Ohms at the output.

Wednesday, September 16, 2009

Building a DI box from scratch (part 3)

Finally, its assembled and working. The chassis took 2 days to build - finished it yesterday. Painted it and wired everything up today. Plugged in my bass and took a listen. It actually sounded really round and smooth. I wasn't expecting it to sound like that, but I'm happy it does. The only problem is the output is a bit quiet. The reason is because there aren't enough turns on the secondary coil in the transformer. I plan to rewind the secondary coil tomorrow with a lot more turns to increase the output volume. More to come. Here's the pics from today:



Monday, September 14, 2009

Building a DI box from scratch (part 2)

In my last post, I mentioned how some people build DI Boxes because it's not that difficult. I should have worded that differently. What I meant to say is, some people "assemble" DI boxes because it's not too difficult.
Yesterday I built the transformer for the DI. Today, I started building the chassis. I was actually just gonna buy a chassis, but I couldn't find what I was looking for so I decided to just build it from scratch. I chose to use some heavy gauge sheet metal because it was relatively easy to work with, yet very sturdy. I laid out a basic blueprint and started cutting away with a pair of tin snips (very difficult). Cleaned up the edges and then started drilling the holes to mount everything. I threaded all the holes so I wouldn't have to use any nuts - plus it looks more professional. It was a real bitch to bend the metal into shape, but after a lot of man-handling I got it there. Tomorrow is building the cover, painting the chassis, and finally drilling and tapping holes for mounting the cover. here's some pics from today:


Sunday, September 13, 2009

Building a DI Box from scratch

Today I started building a DI Box from the ground up, as I wait for some parts to complete my summing mixer.
Some people build their own DI boxes because it's not very difficult. You can buy a Jensen transformer for $100 or a Cinemag for as little as $50. Then 2 1/4" jacks, an XLR jack and a chassis. That's it. I took it a huge step beyond average. I built my own transformer from scratch today. I spent a lot of time researching how to build the DI Transformer properly and have been studying my transformer theory. It took me most of the day, but I built the transformer from the ground up today. This is my 3rd tranny build so far, and its def the best to date. I'll post some pictures of the assembly soon, but here's today's pics of the tranny build.







the primary coil is 480 turns and the secondary is 40 turns with a center tap differential ground. Iron core, 12-1 windings.