The following are my comments and observations as they apply to my recent experience utilizing Tony?s Custom SDA Boards for a crossover upgrade on my 1.2tl?s.
The boards are extremely well constructed. The genius in these boards lies in the design. They are essentially an enlarged version of the original Polk design. Tony didn?t try to reinvent the wheel here. The traces and the component layout pretty much matches the original Polk design. The boards were enlarged just enough to comfortably accommodate all of the larger crossover components (Sonicaps) without any stacking of components or having components hanging over the edge of the board. The boards are very rigid and are not going to flex or vibrate once mounted inside the SDA cabinets.
I no longer had to dread the thought of using the OEM boards; trying to cram and stack components on that little board that wasn?t designed to accommodate the larger crossover components.
Tony?s website, Gimpod.com, which he built specifically for purchasers of these boards, contains all the information and links that you would ever possibly need.
I watched the soldering and de-soldering tutorials that he offers. I ordered all of the materials using the part numbers listed on the website. I wouldn?t have known where to start with regards to ordering all the hardware such as stand-offs and pinned headers without this information.
What impressed me the most was amount of time that it must have taken Tony to redraw the schematics for all the Polk models that this board covers. These are not simply Polk schematics that he posted on his website. They apply specifically to his boards showing all connection points and jumper placements.
Ordering of Materials
I was going to put off ordering materials and the assembly of the boards until after the holidays. Well? I had ordered a set of rings from Larry when I ordered the boards from Tony. I installed these rings right after I received them. They made such a dramatic improvement to my speakers that I just couldn?t stop now.
I ordered all the hardware from Mouser, using the parts numbers provided by Tony, from their website. Piece of Cake.
I then sent an email to Sonic Craft. In it, I asked for matched pairs of Sonicap Gen I capacitors including two custom values (0.25uf and 13.5uf) and one custom value on the Mills MRA-12 resistors (11.5-ohm). Elliot from Sonic Craft replied back to me. He was able to supply the 13.5uf custom value capacitors, but said that he wouldn?t be able to supply the 0.25uf capacitors. What he offered instead, was a pair of 0.22uf caps that read on the high end. He also said that he didn?t have Mills resistors available in 11.5-ohm and suggested an 11.0-ohm instead. I agreed to everything that he suggested and placed my order. I also ordered 24 feet of Cardas Quad-Eutectic Solder from him. Nice people.
Getting up the Nerve
I work every third weekend providing weekend coverage. I had never done any electronics soldering of any kind and decided that this project was no time to learn how to solder on my own. I enlisted the help of a co-worker, an I and C Tech that works the same weekend schedule as I do, to help me solder up the boards. As luck would have it, the hardware from Mouser didn?t show up in time. So, I decided that I would wait another three weeks until the boards were completed. Three long weeks. Ugh.
I had to use up two weeks of paid vacation, or lose it, before the end of the year. There I was at home. Just me and the boards. After almost 2 weeks of staring at the boards, I said to myself, ?you can do this?. I am an Industrial Refrigeration Mechanic by trade. I have done thousands of solder and silver brazing joints in the 30-plus years that I have been involved in this trade.
On Christmas Eve, I went down to Radio Shack and bought a 40-watt soldering iron, a soldering iron stand and some copper braid. I bought some ?? 3M Double-sided tape from Ace Hardware. Ready to go.
Setup and board prep
The first thing that I did was applying the double-sided tape to all the areas on the boards where the caps and inductors would be placed. I even applied tape to the areas where the small inductors would be located. The only area that I didn?t initially apply the tape to was the C6 Cap location. I held off doing this until after the R3, R4 and R5 resistors were attached to the bottom side of the board and the leads clipped off on the topside of the board.
I removed both crossovers from the speakers and separated them from the large inductors that they were mounted on.
For a board holder, I used the box that Mouser shipped the hardware in. It measures 4-1/2?X 6-1/2? X 2?. I cut off the top of the box so it wouldn?t keep getting in the way. It worked slick.
Populating the boards and soldering
I decided that I would populate and solder components to the boards in steps. I chose to start with smallest and shortest (in height) components first. I tackled the jumpers first. I used 18-gauge solid copper wire here. You could also use the clipped off leads from the large capacitors for jumpers here as they also appear to be the same gauge size. I didn?t have any clippings yet, so this was the route that I chose. I also decided to completely finish one board before doing the second one.
That very first solder joint seemed like it took an eternity. Once the first joint was behind me, my confidence level soared and I just took off. First, I finished all the jumpers on the board. I then did the rest of the components in the following order:
1 ? Resistors on the bottom side of the board.
2 ? Pinned Headers. I held them in place with masking tape.
3 ? Small Inductors, 0.22uf capacitor and the resistor that mounts topside.
4 ? Large Inductors
5 ? Large Capacitors
I zip-tied each component as I mounted it to the board. Between the double-sided tape and the zip-ties, those caps and inductors weren?t going to budge. You could turn the board over and not have to worry about the component moving while you were soldering. One comment on the zip-ties: I don?t know if it was the brand that I used (I ordered them from Mouser), but in a couple of cases I had to double-up on the zip-ties to secure the large caps to the board. I used the 6? zip-ties. You may want to use the 8? zip-ties instead.
Taking my time (and several breaks), the first board took 4 hours from start to completion. I did the second board on Christmas Day. It only took 2 hours.
Comments on Solder
I chose the Cardas Quad-Eutectic because of two things: lead and silver. Combine these two solder ingredients together and you?ve got a winner on your hands in terms of ease of use and good bonding.
If this is your first time soldering, I recommend that you get the highest quality solder that you can get your hands on. I also recommend staying away from lead-free solder until you get some soldering iron time under your belt. Leaded solder has a wider temperature range and tends to flow better than lead-free solder. Your solder choice could mean the difference between success and failure on your first project.
FYI- I anticipate that ALL lead-bearing solder will be outlawed very soon. I would stock up on it while you can.
One Addition/Modification to the Board
Trying to be proactive and plan ahead, I wanted to be ready for upgrading the large inductor in about another month using the Solen inductor that other members have already tried and endorsed. I also wanted to be able to simply unplug the inductor wiring from the crossover board if I ever had to remove the crossover for any reason. So, instead of soldering wires directly to the board, as was done with the OEM boards, I chose to purchase a 3-pin header, a 3-pin plug and the crimp connectors (pins) for the plug. I simply snipped off the center pin from the header and then I ever so slightly elongated the P and R holes on the board using a small drill bit. The 3-pin header slipped right in just like it belonged there. I can now unplug the large inductor from the board. I told Tony about what I had done. He liked the idea and said that he may use it if decides to do another run of boards in the future.
Hot Glue Removal
I tried Tony?s recommendation for removing hot glue using rubbing alcohol. All I have to say is ?WOW?! The stuff came right off without a fight. I used 90% rubbing alcohol. I used Q-tips to apply the alcohol and a small pair of needle-nose pliers to pull off the glue. Thank God that I didn?t have to use a knife. I?d still be cleaning up the blood.