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Recap rectilinear mini iii advice

S

Scott32465

New Member
I have read these forums for years as I have shuffled gear in and out of the house, this is my first post.

Picked up a pair of rectilinear mini iii recently in amazing shape but they clearly need to be recapped as the mid -- high adjustment need to be all the way up to get much of either

I have never worked on speakers other than replacement of surrounds and I'm wondering if this is something an amateur can take on without risk to the speaker

Any comments or advice is greatly appreciated !
 
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Scott32465 said:
I have read these forums for years as I have shuffled gear in and out of the house, this is my first post.

Picked up a pair of rectilinear mini iii recently in amazing shape but they clearly need to be recapped as the mid -- high adjustment need to be all the way up to get much of either

I have never worked on speakers other than replacement of surrounds and I'm wondering if this is something an amateur can take on without risk to the speaker

Any comments or advice is greatly appreciated !
Click to expand...

Welcome to AK. If you can handle refoaming drivers, you can handle recapping. Expect to spend an hour or two on each speaker, maybe more since this would be your first.

The basic tools you will need are
  • screwdrivers to remove either the woofer or the rear terminal plate,
  • a soldering iron and 60-40 rosin core solder if the caps are soldered in place (some speakers, like KLH use wire nuts to join twisted wires, but the Rectilinears use soldered point-to-point wiring). If you have not soldered before, practice soldering using spare copper wiring. It is not difficult. Watch YouTube videos for the basics.
  • wire cutters,
  • surgical-style gloves and long sleeve shirt to remove and/or work with the fiberglass stuffing (if that is what is in the cabinet). For acoustic suspension speakers I usually pull the fiberglass out and put it in a plastic trash bag. That wasn't necessary for my Rectilinears.
I have Rectilinear III Lowboys, not the Mini.

The first step is to open up the cabinet so you can access the crossover circuit. Identify all the caps. Rectilinear is notorious for building speakers with different sized caps, so it is imperative to verify what caps are being used. Record the uF or mfd values that are being used. Voltage rating does not matter as long as the new cap has the same or greater voltage rating.

I suggest replacing all the caps with metalized poly caps, such as Dayton, Audyn, Solen, etc. The sky is the limit when it comes to cost. I used the lower cost poly caps for my Lowboys. According to post #7 of the linked thread, there should be a 2.2 uF and a 90 uF cap, but use the values that you have in your speakers if different.
https://audiokarma.org/forums/index.php?threads/rectilinear-mini-iiis-new-owner.788125/

For example, the following 2.2 uF caps are available from Parts Express (I would opt for the Audyn or Solen cap):
https://www.parts-express.com/elect...ylene-crossover-capacitors/capacitance/2.2-uF
A 90 uF poly cap is more expensive and larger than an electrolytic cap, but I believe it is often worth it to use film instead of an electrolytic:
https://www.parts-express.com/Dayton-Audio-DMPC-90-90uF-250V-Polypropylene-Capacitor-027-446
 
Thank you for the detailed response, I actually picked up a pair of old criterion 3x to practice on and spent the weekend figuring out the soldering thing, feels doable, I think I'll tackle the mini's this weekend if I can get the parts in that quick

Wonderful speakers, I'm anxious to hear what they sound like once done !!
 
RTally said:
Welcome to AK. If you can handle refoaming drivers, you can handle recapping. Expect to spend an hour or two on each speaker, maybe more since this would be your first.

The basic tools you will need are
  • screwdrivers to remove either the woofer or the rear terminal plate,
  • a soldering iron and 60-40 rosin core solder if the caps are soldered in place (some speakers, like KLH use wire nuts to join twisted wires, but the Rectilinears use soldered point-to-point wiring). If you have not soldered before, practice soldering using spare copper wiring. It is not difficult. Watch YouTube videos for the basics.
  • wire cutters,
  • surgical-style gloves and long sleeve shirt to remove and/or work with the fiberglass stuffing (if that is what is in the cabinet). For acoustic suspension speakers I usually pull the fiberglass out and put it in a plastic trash bag. That wasn't necessary for my Rectilinears.
I have Rectilinear III Lowboys, not the Mini.

The first step is to open up the cabinet so you can access the crossover circuit. Identify all the caps. Rectilinear is notorious for building speakers with different sized caps, so it is imperative to verify what caps are being used. Record the uF or mfd values that are being used. Voltage rating does not matter as long as the new cap has the same or greater voltage rating.

I suggest replacing all the caps with metalized poly caps, such as Dayton, Audyn, Solen, etc. The sky is the limit when it comes to cost. I used the lower cost poly caps for my Lowboys. According to post #7 of the linked thread, there should be a 2.2 uF and a 90 uF cap, but use the values that you have in your speakers if different.
https://audiokarma.org/forums/index.php?threads/rectilinear-mini-iiis-new-owner.788125/

For example, the following 2.2 uF caps are available from Parts Express (I would opt for the Audyn or Solen cap):
https://www.parts-express.com/elect...ylene-crossover-capacitors/capacitance/2.2-uF
A 90 uF poly cap is more expensive and larger than an electrolytic cap, but I believe it is often worth it to use film instead of an electrolytic:
https://www.parts-express.com/Dayton-Audio-DMPC-90-90uF-250V-Polypropylene-Capacitor-027-446
Click to expand...
I didn't see those 90uf caps at PE when I did my mini lll's. Maybe PE didn't carry them then? I used two 45uf electrolytics I found at Partsconexion. Even after recapping, the mini's sounded very wooly. Like a blanket was over the speakers.
All the drivers checked out. I didn't keep them long.
 
Thanks again RTally, reread your post and I'll open them up in the next day or two to verify cap values before I order parts

Thank you Lavane, I think that is some of what I'm hoping to solve

Discouraging that a recap didn't solve for you, however I like them very well in many other ways

Worth the work to find out and good experience for a novice Like myself
 
Hay,

I’d grab a pair of mini III’s in a heartbeat. After a recap mine blossomed, then kicked ass. At the time I had larger power amps and was able to keep them at a solid 100 watts without issue. Damn fine little rigs. They’re 4ohms, but still easy to drive. My largest amps today are 40 watts, still plenty. I did find the grills choked the highs and muddied the mids, so removed when listening. And since they’re so small, you can pack them away with ease when necessary.

Biggles
 
drbiggles said:
I did find the grills choked the highs and muddied the mids, so removed when listening. And since they’re so small, you can pack them away with ease when necessary.
Click to expand...

Rectilinear had trouble with grills. My Lowboys have a thick, plastic lattice grill. With the grills on, the speakers sound like a thick moving blanket is thrown over the speakers. With the grills off, they sound fantastic, even when they are on the floor.
 
RTally said:
Rectilinear had trouble with grills. My Lowboys have a thick, plastic lattice grill. With the grills on, the speakers sound like a thick moving blanket is thrown over the speakers. With the grills off, they sound fantastic, even when they are on the floor.
Click to expand...

Agreed. Tall ones, squat ones, mini ones, the grills need to be removed for playtime. Thankfully, it’s not an issue. And, there’s no way in gosh Iam disposing of the orange originals.

Biggles
 
Bringing this thread back for an encore performance.

I just got a pair of Mini III's for a terrific price. They sound pretty amazing already, but I'm prepared to go in and do the recap based on the information you've given.

However, the 4 ohm thing is freaking me out a little. I've got a Sony STR-6060F, which seems a little under powered for them, and a Yamaha RX900U (plenty of power but it says on the back 6 ohm minimum). I've been using them with the Yamaha, and it runs a little warm, but the weird thing is just how much bass there is. I've run the bass pot down as far as it'll go and it's still boomy as hell.

Is this because of the 4 ohm thing? Should I try them with the Sony? (I run the Sony with Rectilinear Highboys, and I think it's the perfect match.... the best stereo system I could get in 1968. Wait...It isn't 1968?)

It's a small room and I'm not that worried about overpowering them, but what exactly do I need to run 4 ohm speakers? Amp suggestions?

Thanks in advance.
 
They're small, efficient speakers that are 4ohm. I ran mine with original early 1970s Japanese receivers in the 10 to 20 watt range without issue. Also, fed a solid 90 or 100 without issue too, I think. My point is, if your receiver is functioning properly, and you dont run it full bore for 11 hours, you're probably fine.

If you purchased modern English monitors that are 4 ohm and we're reviewed with power amps of 200 watts, I'd say No.

Biggles
 
Great speakers!
Had a pair but woofers blew out.
Kept the 2 good Philips mid ranges though.

I have the high boys now recapped.
 
drbiggles said:
They're small, efficient speakers that are 4ohm. I ran mine with original early 1970s Japanese receivers in the 10 to 20 watt range without issue. Also, fed a solid 90 or 100 without issue too, I think. My point is, if your receiver is functioning properly, and you dont run it full bore for 11 hours, you're probably fine.

If you purchased modern English monitors that are 4 ohm and we're reviewed with power amps of 200 watts, I'd say No.

Biggles
Click to expand...

@drbiggles, I was hoping you'd turn up, as you are my guru for all things Rectilinear.

When I get off work tonight I'll hook the minis up to the STR6060 and see if the bass response is more in line with what I was hoping for.

In any event, I feel more confident about the whole 4 ohm thing. Thanks.
 
Play with placement too. Slammed up against the back wall, in and out of the corners, up high and down low. I remember wishing I hadn't sold mine. I still havent run across another pair. They're small enough to pack away and save for later. The guy I sold them to came back a couple of years later for a repair, a mid had come loose. He did not want to sell.

Biggles
 
Reviving this thread.

I had the Mini III's in a closet for the last three years while I worked on other stuff.

Now I'd like to get them going. I know they need a recap. No problem. However, how the hell to you get the grill covers off without damaging the surrounding wood? Any ideas would be appreciated.
 
The grill covers are nailed on so removal is a PITA. I used a plastic auto trim removal tool and inserted it between the grill and the speaker cabinet beginning at the bottom. Once you get one section loose, the others follow pretty easily. It is easy to damage the grill cover support, which is made of homasote board or similar material. You should be able to reuse those, but I have also made new ones out of thin plywood. I never worry about saving the original grill cloth, as it is hideous to look at and does nothing to help the sound. Looks like the curtains in your grandmother's house. I have / had eight pairs of Rectilinears and none of them have original cloth installed once I get through recapping and refinishing them. I prefer the traditional black grill cloth look.

 
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