My Second Express Build - In progress

[Omar]

So I finally found some time to start to put together my second Express. My first attempt at the an Express was more of an interpretation of an Express based on the schematics available at the time. From the pics of Francesca I've been able to make my second build more of a clone than an interpretation, although this build has a number of small differences:

- Chassis dimensions are a little smaller due to me re-using my Bob Burt cab from the first build
- I had the chassis clear anodized since it scratched so easily and was driving me crazy
- IEC socket
- 18 watt pilot light
- PEC pots
- Different board material with turrets
- There is a hole in the back of the amp for a post-PI master volume that I will eventually put in

Using the pictures of Francesca I have tried to make the wiring as close as possible, even trying to match the color. For example, on the heater wiring I tried to get the same number of twists and position it exactly like Francesca's. I know it's a bit crazy, but my OCD wants me to make everything neat and clean. Instead my OCD is making me copy the sloppiness!

So here are the pics so far:








Hopefully, I'll finish the amp this weekend.

Omar

[908ssp]

You know that the anodized surface doesn't conduct electricity? You have to scrap through it to bare aluminum at every ground point and use a serrated or shake proof washer to dig into the aluminum. The anodizing converts the surface to aluminum oxide a very poor conductor.

[Omar]

You know that the anodized surface doesn't conduct electricity? You have to scrap through it to bare aluminum at every ground point and use a serrated or shake proof washer to dig into the aluminum. The anodizing converts the surface to aluminum oxide a very poor conductor.

I remember reading that somewhere and have scraped the areas where I'm grounding. One thing I thought was curious was that I used my Fluke before I scraped and it was reading that the ground points were already conductive?!?

Omar

[Funkalicousgroove]

Looks great!! What are you using to hold your filter caps in place?

[Omar]

Looks great!! What are you using to hold your filter caps in place?

Thanks, Funk! I used a hot glue gun to hold the filter caps in place.

Omar

[mac0611]

lokks real nice, omar. What kind of power supply caps are they?

[UR12]

Looks great Omar!!! keep us posted on how it's coming.

[Mark]

Dear Omar

It is looking like a very sweet build, love to here your thoughts on it once you've finished building it. I'm wondering if it will sound exactly like the previous Twreck amp you've built or quite different?

[908ssp]

You know that the anodized surface doesn't conduct electricity? You have to scrap through it to bare aluminum at every ground point and use a serrated or shake proof washer to dig into the aluminum. The anodizing converts the surface to aluminum oxide a very poor conductor.

I remember reading that somewhere and have scraped the areas where I'm grounding. One thing I thought was curious was that I used my Fluke before I scraped and it was reading that the ground points were already conductive?!?

Omar

Great better safe then sorry.

[Omar]

lokks real nice, omar. What kind of power supply caps are they?

Mallory TC series - just like Francesca!

[Omar]

You know that the anodized surface doesn't conduct electricity? You have to scrap through it to bare aluminum at every ground point and use a serrated or shake proof washer to dig into the aluminum. The anodizing converts the surface to aluminum oxide a very poor conductor.

I remember reading that somewhere and have scraped the areas where I'm grounding. One thing I thought was curious was that I used my Fluke before I scraped and it was reading that the ground points were already conductive?!?

Omar

Great better safe then sorry.

I did some more testing last night and and it looks like they must have plugged all the smaller round holes when the annodized it because the surface and the square mounting holes are not conductive but all the pot and screw mounts seem to be conductive?!?

Omar

[908ssp]

Omar that is probably due to poor acid circulation not plugs. In most anodizing operations they just hang the parts from a rack. Then it is lowered into the acid the anodes are hung in the tank and a current is passed through the acid into the chassis. If the acid is stationary and not agitated like in small holes the anodizing doesn't get as thick.

I have heard that grounding is a issue so I just wanted to remind everyone when using an anodized chassis to make the effort to scrap off the anodizing from the start. I can imagine chasing a bad ground when you're finished would be a real pain.

[Allynmey]

Absolutely beautiful Omar !!!!

Allynmey

[loverocker]

Yup - beautiful work.

Nerdy question - did you use a 3/8-inch grid for the turret layout? I'm a bit confused as to what Fran had after the perf boards that url2 found had a smaller than (I) expected hole spacing.

I really like your flamey faceplate. I bought some flame veneer mahogany for my clone, but it's soooo thin. Is yours laminated on something else - plastic/alu?

[Omar]

Yup - beautiful work.

Nerdy question - did you use a 3/8-inch grid for the turret layout? I'm a bit confused as to what Fran had after the perf boards that url2 found had a smaller than (I) expected hole spacing.

I really like your flamey faceplate. I bought some flame veneer mahogany for my clone, but it's soooo thin. Is yours laminated on something else - plastic/alu?

Thanks, loverocker!

For the turret layout I used Wreck2k4's layout in the Files section. I modified it a little bit to allow for a post-PI master volume.

The faceplate was from Bob Burt who also built my cabinet. The wood is eucalyptus to match the cabinet he made for me. It has a really nice flame quality to it. I had it laser etched for the labeling. The only issue is that it's pretty thick and the pots, jack and switches just bearly fit through.

Omar