Post by Bigman80 on Nov 4, 2023 20:10:12 GMT
After getting the back panel sorted it was time to do some dry fitting of the traffo, rectifiers and PSU board. The traffo is a 600VA premium audiofile (fool) bling version from Toroidy and it is MASSIVE. So much so that the rather large enclosure feels small after installing it.
It comes with a mounting plate, which is needed because the wires exits the traffo on the underside. 
I placed the traffo as close to the back as the soft start mounted on the back plate would allow. I did not expect to run out of space, but the dry fitting of the parts revealed that there was no excess space anywhere.
In the pic below I have marked out the outlines of one of the alu bars keeping the enclosure together. I removed the anodizing in this area. I did not want to scrape off the anodized layer at random places so I ensured safety ground continuity throughout the case through the alu bars. I did have to scrape the heat sinks as they don't attach to the alu bars.
Below the rectifiers are fitted and the secondaries connected.
It was a close call, but I did get just enough clearance for everything. At this time I did not think about it, but the on/off switch proved to be a challenge to squeeze in in front of the caps...
One thing I had decided before starting the build was I wanted the wires directly soldered to the 686 boards. That meant removing the Molex connectors, 3 per board.
Yes I know... I am embarrassingly obsessed with these things. My thinking is, any positive effects of the ultra pure triple C input and output wires would be negated by the molex brass pins.
So the goal was set, and I was determined to remove the connectors even though Tom from Neurochrome advices against it.
To get to the underside of the board one has to dismantle the pcb from the aluminum cradle it's mounted in. That was easy but a little unnerving since I do not have ESD safe straps and equipment. I figured the boards cannot be THAT sensitive...
The input connector was a breeze to remove with my desoldering gun. This will be an easy task I thought. Well, no!!
Take a look at the picture below. That's the speaker outputs after removing the solder with the desoldering gun. It's such a snug fit that the desoldering gun wouldn't free the connector.
I came to think of a desoldering trick I learned from youtube. The old copper wire ring. You take a piece of sturdy solid copper wire and bend it to snugly fit the pins you want to remove. Add solder and heat and voilà, the connectors drop right out. Clean the pcb with IPA and you're done.
Pleased with how this went I assembled the 686 boards back into the alu cradle and continued with braiding the triple C input wires.
Yes I know, what a terribly messy table. This table is the only place in the house where tools and parts are allowed so I try to make the most out of it
. The drink in the beer glass might actually be cola. That would be an exception, as I try to enjoy a nice ale or two during the sessions. 
After getting the connectors out I started with drilling and tapping the holes in the heatsinks. This proved to be much more challenging than I initially thought.
I did not want the holes to be visible from the outside, so I drilled shallowish holes the best I could with my battery powered hand drill and followed with a normal tap... Big mistake. If one is to tap end holes, one needs an end hole tap which will raise the machined metal out of the hole instead of collecting it inside.
I messed around with the holes quite a bit before I finally managed to do them all. Well, almost all, as I did break one drill tap and left it in the hole. I also lost the threads on a couple of them, and had to enlarge the threads from M4 to M5. If anyone is in the same situation, please be aware that you have to marginally increase the hole size on the 686 alu cradle for the M5 screw to fit...
I don't have good pictures of this process. I think I was so irritated with the tapping that I did not remember to take pics...
This was one of the most diffucult stages of the build for sure.
One of the boards mounted, input wires soldered
Dry fit of the PSU board. PSU wiring braided and ready. The caps felt very flimsy after soldering so I decided to put a piece of plastic foam in between the cap rows and tie them togehter with zip ties. This made a world of a difference. Much sturdier now.
Speaker output wires soldered to the board. Pic is prior to cleaning the flux with IPA. The wires are SAEC 650 triple C speaker cable wires. They fit the 686 boards perfectly. The only downside I have found with the triple C wires, small or larger gauge, is that the wire jacket creeps a lot when soldered.
In the pic below the build is almost finished. Well, input wires and power wires still need to be soldered, and the front panel with on/off switch is still missing.
That's all for now. More to come soon
