Ohm Walsh 3 Recap Challenge

[FireGuruMN]

I bought a pair of Ohm Walsh 3 speakers about a year ago. They sounded fine but as I have learned there is always room for improvement through replacing old capacitors. But it seems Ohm makes almost every step of the recap process a challenge. I found some useful threads that got me started on the path but nothing that took me all the way to the finish line. So here is my story.
Obviously, remove the "top hat" by removing the 4 screws. You will need a long shaft screw driver to do this easily. I used a drill with a long extension driver. I'm lazy.
Inside you will find a couple of sheets of insulation supported by a plastic screen. Carefully remove the insulation but it will probably fall to pieces no matter what you do. It can be replace if needed. Remove the screen. I trashed mine and replaced it with regular bug screen from a hardware store.
Then you will have this nightmare view:

The crossover is 3 feet down inside the speaker with cross beams all in the way. oh, and it's stapled and glued in place. In my case there was an entire haunted house full of spider webs and egg sacks.
Step one:
remove at least one cross brace or you cannot get to anything. Some good news: The braces are glued in with hot glue. Get a heat gun. A good $25.00 investment anyway. Mark the top side of the brace, they are mitered to fit the odd angles of the speaker. Hold the heat gun on the ends of the cross brace for a minute or so and the glue will melt enough to twist the brace off. On my first one I removed two but I only removed one for the second one.
You will find three blocks of wood glued to the sides to support the inductors. (curious that the spell check flagged that as a misspelled word on an audio forum).

Again, these are also held in place with hot glue. It takes a couple of minutes to melt the glue well enough to remove them without damage. Be patient. DO NOT pry against the inductors. They are soft metal and will break easily. I would have worn a mask but they are needed for medical purposes in the current pandemic so I donated mine. It gets pretty stinky with burning cob webs and such.
Here is what I removed:

Looks like they were cutting up old speakers to make some of the blocks. How's that for direct recycling!
Now it gets hard. Pull four staples out of the cardboard crossover/switch plate. I used a lineman's pliers and pulled straight up. Wear gloves or you will certainly skin some knuckles when they pull loose. The crossover is hot glued in place again. It takes a long time to heat it up enough to soften the glue. 5 minutes in my case. Then turn the speaker upside down and use a FLEXIBLE puddy knife to slide in around the edges of the crossover hole and free up the crossover. DON'T let it drop or the inductors will break. Maybe put the speaker sideways as it frees up. You will probably leave some behind:

You will be rewarded with this in your hands:

Continued. . .

 

[FireGuruMN]

There is a mix of film capacitors and electrolytic. The smaller film capacitors I replace with new film capacitors. That may not be necessary but everything made today is better than anything made 34 years ago (opinion). So out they go. The electrolytic caps have to go regardless (opinion and experience). There are two 33uf caps electrolytic caps. I have never found a schematic of this crossover on the interweb to determine where if those are bypass caps or if they are in the audio path. I played it safe and replace them with film caps. Then there are two large value electrolytics (375uf and 470uf). There is no way I could afford that much expense or real estate in the speaker to replace those with film if they even make them. My usual cutoff is 35uf for film caps. Anything larger than that I go with electrolytic. Some of the film caps are wired in parallel. I could not determine that before I pulled the xover out so I ended up ordering separate caps in case they were switched somehow. In reality they could be combined into a single cap. I left all the resistors in place as well as the inductors. Here is what I ended up ordering (per speaker) (parts express):
1 Solen 12uF 400V Polypropylene Capacitor Part # 027-572
2 Solen 33uF 400V Polypropylene Capacitor Part # 027-592
5 Solen 3.9uF 400V Polypropylene Capacitor Part # 027-548
1 400uF 100V Electrolytic Non-Polarized Crossover Capacitor Part # 027-376
1 68uF 100V Electrolytic Non-Polarized Crossover Capacitor Part # 027-356
1 300uF 100V Electrolytic Non-Polarized Crossover Capacitor Part # 027-371
1 80uF 100V Electrolytic Non-Polarized Crossover Capacitor Part # 027-358
Some values are not exact matches. The 12uf should be a 13uf but who's counting.
There is an interesting bit on the crossover that I did not research or replace:

A little blue disk with resistors glued to it. I'm guessing a thermistor to protect something as the resistors heat up. Regardless I left it in place. It is my personal preference to leave existing components on crossovers BUT ELECTRICALLY REMOVED. There is usually enough room to add the new parts. In this case some of the components would have been hard to remove because of the glue. No rocket science to replace everything. I had to add some leads to the 33uf caps to get them in the circuit. The electrolytics are wired in parallel to get the correct values. Lots of heat shrink to keep electricity flowing only in the correct places.


I tied everything down with hot glue. I also added some hot glue to existing inductor wiring because it seemed to be floating all over the place. One of the cores on the small inductors fell out during the process. I glued it back in once I found it.
Spray some deoxit into the switches. I did this from the operator side because there were no good holes on the back side. Since this is cardboard, hold a rag over when you spray so the cardboard does not sog out. Gravity will drain the deoxit into the switch and then work it back and forth 30 times so it does its job. The switch will loosen up as you work it.
Now the harder hard part: There is a capacitor in the top hat. Again, I did not go through the schematic to determine why this could not be on the crossover with its friends but who am I to judge. How to open the top hat: You guessed it, more heat:

I screwed the top hat down to a scrap plywood plate so I could get some leverage. Slowly work your way around the base and heat up the seam. In my case LOTS of dust blew out so maybe start with an air compressor outside. And the woofer is right inside the bottom so use as little heat as necessary. Less than 30 sec at one location. Eventually the top will pull apart at the seam and you can extend the separation around the seam pretty easily. You will be rewarded with this view few have ever seen:

One capacitor and 3 "light bulbs". The light bulbs act as current limiters. But 2 speakers and 3 light bulbs? Again, I just work here.

Cut the old cap out of the circuit and glue the new one on top (personal preference).

Feel free to add your own signature and time stamp if desired. Like those books they leave on top of 14,000foot mountains.

I heated up the glue at the base and pushed the cover back on. Sealed away for another 34 years.
Continued. . .

 

[a_retent]

I bought a pair of Ohm Walsh 3 speakers about a year ago. They sounded fine but as I have learned there is always room for improvement through replacing old capacitors. But it seems Ohm makes almost every step of the recap process a challenge. I found some useful threads that got me started on the path but nothing that took me all the way to the finish line. So here is my story...

Perhaps you missed this thread:
Ohm Walsh 2 recap

I'm fully aware that thread is about the Walsh 2s but cabinet construction, crossover mounting, damping material placement, hot glue usage, etc, are the same for both and was pretty extensively covered. I do like your photo documentary, well done and keep up the good work!
Best of luck in your endeavor, I like to think the Walsh line of Ohm speakers are certainly worth investing into.

 

[FireGuruMN]

This amused me:

Some acoustical engineer spend hours on a calculator and in a test bench exactly designing the diameter, length and position for this port and the carpenter decided he needed a brace there so here is what you get.

Before reassembling I hooked the top hat up to the crossover and measured the resistance to ensure nothing was going to blow up. It read 68ohms which is more than a little weird. But the untouched speaker read the same so I got over it. I hooked up to my bench amp and it made sounds. The various switches on the crossover changed the sounds in various ways so I figured I was good to go.

I don't have any more pictures. But there is not much more to the story. I tried to hot glue the crossover back into the base but the hot glue cooled before I could position the crossover correctly so I just globbed some wood glue down there and pushed it in place. I held it down with 4 screws and let it dry. Good luck ever getting that out in 34 years. Maybe we will have miniature drones or "waldos" for you Heinlein fans out there in 34 years so no one will ever have to remove it again.

As I always do, I left one speaker original and the other recapped so I can do a comparison. And as always the new speaker had clearer vocals and brighter highs. The bass seems untouched. So I redid the other speaker and gave them a spin. My personal preference is to have the low end switch set to high and the tweeter switch set to low. That might be due to the wrong cap value in the top hat. I have no idea where to set the perspective switch, front, rear or middle? who knows? I went with middle so as not to upset the republicans or democrats.

No, I did not replace the speaker connectors with overpriced binding posts. My eventual plans is to build a permanent base for the speakers and get rid of the wheels. There is another post somewhere showing that. Then I will put overpriced binding posts on the base and not need to mess with the ones on the crossover so much.

Yes, these are wonderful speakers. The bass they pull out of that little woofer is incredible. smooth and not boomy as so many small woofers end up sounding. I do not have the space to properly set them up ever since I landed a pair of JBL 4435's. They are the 800 pound gorilla in the room. Actually just 500 pounds but who is counting.

Next up: Dahlquist DQ10. Hopefully I don't run out of speakers or speaker parts before the pandemic is over.