T15 build - My first DIY kit

[theposterkid]

Hey everyone,

I've known about SCA for years now, if for no other reason than the usual ads in Tape Op. I came across a rack of the pres in Denton while mixing FOH, but I don't think I got a chance to use them at the time.

This week I finally placed an order for two T15 mic pres and the chassis & power supply. The package arrived yesterday, and I opened up the box and got started immediately.

This project is something I've been dreaming of doing for years! Previously, the only soldering I had done was repairing cables, and de-soldering/soldering AM10 op amps in a Quad Eight console. I could count on one hand the number of components I had soldered onto a PCB.

For anyone considering this kit, be SURE to get a small tip for your soldering iron, as suggested on this website. I had the proper size called for, and even that sometimes felt a little big as some pads/joints are small and sometimes packed close together.

However, the design and layout of the PCB makes things easy. The parts and their values (in the case of the resistors) are clearly listed on the PCB.

It took me about 7 hours, including a few interruptions to deal with other tasks, a quick lunch, etc. Everything tested out fine on the DMM, so I went home happy.

This morning, when I actually plugged a mic in, I had some problems. As I increased the Gain, the signal would gradually go away, and there were loud pops each time the Gain knob was turned. The pre was passing signal, with both dynamic and condenser microphones, but something was not right. Then I noticed some weird noises, and heard very audible distortion as I got to the 3rd and 4th Gain position. The pops got louder as I went from a higher gain setting down to the lowest gain setting.

I emailed Tim and he replied with suggestions within 15 minutes! Talk about great customer service! He recommended that I replace U1 with a new 1512. After I did this, everything checked out perfectly! Tons of gain, and a very clean sound. I must have damaged the original IC during installation, perhaps with improper handling, causing a static charge to the pins.

Is it just me, or are the black plugs that cover the Gain and Trim holes on the front panel extremely difficult to remove? Is there a trick that I am overlooking? The two little plugs for the 48v and Polarity are easy to remove, however.

I hope to actually hear it in the studio this weekend on some instruments. I have attached some pictures of the build process in the post below.

[theposterkid]

Here you can see that I have two T15 preamps laid out, along with the cabling for the power supply on the right



Here I have the T15 PCB laid out and ready to stuff



I've begun stuffing resistors



Getting there....



...and that's everything.



All done! Now I just need to build another 7 of them...

[theposterkid]

Update: I built my 2nd pre, this time in just under 5 hours. It worked perfectly right off the bat!

I did get a chance to use my first T15 on a session this past weekend. It was on electric bass guitar. The amp was an Ampeg B18 fliptop, with a Beyer M380 mic. Sounded great! I didn't get a chance to A/B it with other pres as I was in the heat of the battle, but I was extremely pleased with the sound...