JKent

Isn’t that what they put in Rolls Royces?

Thanks. Very helpful. I actually made my ports already and was very surprised to see how shallow they are in the drawung. Looks like just 3/4" or the thickness of the front baffle. I had originally planned to use a 4" round port but then made a rectangular one of wood but it's 2" deep. Thought that would be useful for experimenting with the amount of stuffing in the slot but the picture at the top of the linked page shows a rather thin piece of fg. Back to the drawing board?

I recently acquired some speakers with very nice walnut cabinets but crappy drivers. My plan is to build some Dynaco A25 clones using the GRS replacement drivers from Parts Express. Here's my question: What are the dimensions of the slotted aperiodic port? My clones will resemble the A25s pictured in this thread with the slot on top but I assume the dimensions were the same, top or bottom. I’m primarily interested in the DEPTH of the port TIA Kent

Here's a shot of the back with the new 5-way binding posts. I put them to the side because space is limited in the middle. The old hole is blanked off. The pic also shows my "custom interconnects." The originals had a flat color coded 4-conductor cable but that was missing. Fortunately I had just pulled a bunch of ~20" wires from a speaker (my next project--Dynaco clones). Trying to figure out how to tie them together I Googled "4-strand braid" and found lots of instructions. I had the crimp connectors and heat-shrink tubing on hand so these cables were virtually free. I like the look. Still need to paint the 4th screw head yellow.

Got these recently--just the contour (crossover) boxes--not the speakers. One box cover looked just awful inside--all moldy. The guts of that box were a little dirty but not bad. Everything else was good but 2 knobs were missing. Wood veneer had some small chips and one gouge or dent. First step was to scrape the mold off with a putty knife, then brush on pure bleach. Rinsed it off and dried with a hair dryer. The gouge was steamed out. Wood was stripped using lacquer thinner, steel wool and paper towels. The chips were filled with a mixture of epoxy and walnut sanding dust. The cabinets aren't finished yet. Still have to decide whether to use lacquer or oil. Also have to get some yellow paint for 2 of the terminal screws. This was odd: The instructions say "The terminals marked 'GND' and '8 Ohms' on the Contour Control's rear panel should be connected to the corresponding speaker terminals on your amplifier". Surprise! KLH used some spare FM Antenna terminals for this pair! So I decided to remove those, blank the hole with sheet aluminum and install 5-way binding posts. That's a first for me but I think it's an improvement. All of the caps were replaced with ones I had on hand: Two 50uF NPEs, one 16uF Erse mylar, three 4uF Dayton polys and one no-name 3uF mylar. I used to replace all of the resistors but Roy advised me that the only truly undersized one is the 5 Ohm 5 watt in the woofer circuit so I replaced that with 2 10 Ohm 10 watt Rs for an effective 5 Ohm 20 watt. Because of the two missing knobs I used some stove style knobs to replace them. I think they look right, with a vintage vibe but I just bought a single "parts donor" crossover with 4 knobs, so I can use originals and have 2 to spare. I tested these two with some raw drivers just to make sure everything works.

Here's the latest revision; Rev 7b as of March 2024. Please disregard the old revision (Rev 2) in the Library. Thanks again to Gene for resizing this. Kent Rev 7b reduced.pdf

Glenn is the expert on this, but I'll take a crack at it Before clamping, dig out as much crumbly/swollen stuff as you can. Sorry I don't remember what the finish is. I'd try wiping it with Lacquer thinner first. If that softens it, it's lacquer. If there are dents, where the fibers aren't torn up, you can steam them out with a damp cloth and an iron (even a soldering iron). Good luck. Worthy speakers. Kent

I was wondering why no one picked up on that. Pete has mentioned good subs for other drivers in the past and it looks to me like an adapter plate could be made, even without a 3D printer. Maybe I should add a couple to my next Mouser order. Anyone plan to investigate?

Forget about stacked Advents. Your stack rocks!

Are you serious? For phony Advents? Where do you live? It seems to me a lot of people are getting rid of speakers that are "too big." I recently got some very nice Snells for free. And a CSP member has some AR-9s listed in the FS section for $800 which sounds to me like a steal if you have room for them and happen to live in New England so you can pick them up. But to your point: I doubt that I know any more about xo's than you do but it seems to me that, since your Polks are ported, you could simply splice into the tweeter wires, run long wires out through the port and attach L-Pads, then adjust them from your listening position until you find the setting that sounds right. Then solder in your fixed resistors. Kent PS: Looks like you posted while I was typing but I still think my suggestion would work if you want a reversible fix

Nice work. Enjoy the music. I remember commenting to my audio technician friend that it was my impression that all Canadian hi-fi was excellent. He said "well, not ALL...." He named a company but I've forgotten the name. Electro-something? He said it was an attempt by the gov't to re-train lumberjacks to build audio equipment. Apparently not high quality. Sounds like a Monty Python bit to me 😄 I've always lusted after Bryston gear but never took the plunge.

Yeah, those 47s are definitely new. And 47 is close enough to 50. You'll notice in my re-do, some caps and some resistors are close but not exact values. Speaking of which, it may be too late now but I always recommended replacing all of the 5w resistors with 10w. RoyC looked into this and identified just 1 or 2 that had to be replaced. I have to search my notes. One is the 5 ohm in the upper left corner in my pic. I'll try to get more info. Kent PS: OK. I think Roy said that 5 Ohm resistor in the woofer circuit should be 15 0r even 20 watts. There's a 15 Ohm in the mid circuit. I think it's the one in the middle of the board. That one's OK but could be bumped up to 10w. The other 5w resistors are fine. PPS: OOOPS. We were typing at the same time.

Yeah. Beer softens me up too 😄 Your 4x's have a mesh cap, essentially. That should clean it up nicely but if the wood is thirsty, Howard recommends following up with their Feed n Wax. I use Aleene's on paper cones. Don't know how it will be on poly. I use that nasty nitrile based glue for plastic cones. Looking forward to more posts. Not familiar with that brand but those seem very nice. I think in general Canadian speakers are quite good. I'm told the Canadian government helps speaker manufacturers with R&D. I'd say they were a great find and a good project. Kent

That's right. Is that your only double cap? Sometimes KLH used a double cap but both red leads went to the same point, so a single cap can be used instead. Kent

Welcome back "cousin" 😉 What a great find! (and great spouse!). Not sure about the dust cap. How does the woofer do with a push test? If it springs back maybe try a little white glue around the cap. If it still springs back use some of Roy's goo on the surrounds. Regarding the caps, I hope someone with more expertise chimes in but I don't see a problem. What are the implications for ESR? I dunno. I do know, from working on Snells, that Peter Snell was an advocate of "bundling" caps, so you're in good company. Kent