• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Inside the Minimus 7: repair and restore

My HT system uses five Minimus 7s and a JBL sub. I installed the eBay crossover kits in just the front three. It sounds great to me. I was afraid of blowing the speakers with my 100 wpc receiver at first, but that hasn't happened. I use it exlusively for movies. The Vintage Marantz/AR system in the same room is used for music. The two systems share the same subwoofer and it works well. I just have to remember to turn off one system before I turn on the other. I don't know what will happen, but it can't be good.
 
I just bought some minimus 7w's from the bay and replaced the woofers with the kit I bought at the same place. The woofers I removed both say "WOOFER 1234 8 ohms". One has the part number 0509YY stamped on it. The other has a paper sticker on the back, and it says "KOREA 1992 5.6". the lattter woofer came from a speaker made in Korea, and the former Japan. They look exactly the same otherwise. The replacements have metal cones and beefier magnets. They sound great as nearfield monitors.

The thread by Zilch has a guess about where these woofers come from, but I can't remember which page. It's not parts express, though. The thread concluded that the original drivers were fine, so when I do this on the next pair I get, I am going to use the thread's conclusions and build the PZ 2.1 crossover. Will probably keep these woofers for a while until I complete this project. Otherwise, I would have been happy to sell them.
 
asdf, I did find the link that Pete B posted about a replacement woofer from mcm. I looked at it, but it was a little different than what I got in the kit on the bay. This looks like what i got: http://www.mcmelectronics.com/product/55-1856&cid=prodCrossSell. I do not know if that one is comparable enough to the original to be a drop in replacement, because that stuff is over my head. I sure would like to know if it would fit the PZ 2.1 crossover mod posted here.

Anyone?

By the way, these are a little shallower than the one Pete B posted, and that will make a difference. There isn't much room for a deeper woofer.
 
M7s as upgrade to Klipsch ProMedia 2.1

I just replaced the sats on an older Klipsch ProMedia 2.1 desktop system with a pair of M7s. A nice easy upgrade...the subwoofer seems to be pretty nicely matched to the M7s and the extra bass comes in handy.

A very nice 2.1 setup without having to fuss with an amp and separate sub, possibly a DAC too.

Oh, and as an audio snob, I find it kinda funny to have the Realistic logos staring at me. :)

They are great little speakers, more than enough for a home office desktop 2.1 system.
 
I had a pair of Minimus 7's stored away that I had purchased new in 1989. I read the above posts and thought that I'd see what I could do to beef up their performance to use as better quality pc speakers. Upon dismantling, I changed the tiny 4.7uf electrolytic caps to a larger Solen Fast Caps. I also did my usual "ahhh" test by putting my mouth in the cabinet woofer hole and yelling "Ahhh" to see what came back (with and without the stiff stock standard white acoustic wadding in the box). I was disappointed that the wadding did nothing noticeable, and there was a definite horrible after-glow of sound in the box - lots of reverberation that must have been colouring the sound an awful lot!. I changed the wadding over with some denser 1" acoustic grey foam to the inside back and top of the boxes and retested with the "Ahhh" - WOW - what a difference!! I put everything back together again and fired it up. Honestly, I used the hate these speakers, which is why they were in storage for 26 years. Now, I can't believe what a difference such simple mods could make. Do these two simple things and you'll see what I mean - noting else is required (don't fuss with changing binding posts, wires, installing bypass caps etc.). Enjoy!!
 
I love this thread, and it certainly takes me back in time. My very first two-channel system utilized Minimus 7 speakers with metal cabinets. Considering their cost and size, they sound more than decent, and it's understandable that they have a sort of cult following now. I still have four of them in storage, and may recap them for use in a painting studio system.
 
drspiff said:
Another mod for the Minimus 7 is to replace the funky spring wire connectors with dual 5-way binding posts. The casting where the spring clips mount is perfect for binding posts. Here is a shot of one that I modified.

attachment.php
Click to expand...
This is an old post but I think I have the same pair as no terminal cup ,40-2039a, where the spring loaded terminals are recessed in the cabinet. How you able to change out the binding posts ?
 
For the Minimus 7W in original walnut veneer, might anyone happen to know the best available speaker grille pegs required to replace a couple of broken ones on my otherwise mint condition speakers?
I'm hopeful that this is the sort of question that Audiokarma excels at answering...
 
Hifibythekg said:
For the Minimus 7W in original walnut veneer, might anyone happen to know the best available speaker grille pegs required to replace a couple of broken ones on my otherwise mint condition speakers?
Click to expand...
Minimus-7W uses Tinkertoy style grille pegs.

z-factory.png

These are similar to pegs used in some JBL and Pioneer speakers. Though I'm guessing dimensions are different.

The closest dimension-wise I've found to Minimus-7W pegs are straight cylindrical type, which are friction-fit rather than having a slight snap-in action like the originals.

There are Chinese ebay vendors who offer a metal peg with plastic cup:

zhome2015_grill-pegs2 (Small).jpg

But the shank diameter would likely need to be machined down a bit. And the bare metal would appear conspicuously non-stock.

Probably a better prospect is a plastic set offered by UK ebay vendor "jellyfishaudio" (no affiliation). Dimensions look close -- IF I'm reading things correctly:

z_jellyfishaudio_grille-mtg (Small).jpg

Even if these fit well into the grille sockets, the smaller diameter flange could be an issue if it reveals marks or marring beneath the area covered by the original wider flange. That remains to be explored. I'm ordering some of these to experiment with. If found not suitable for 7W, they'll go into other small speaker projects.

I haven't made an exhaustive search. Someone else may know of a product that's closer to stock.
 
Last edited:
Great post. I agree that the Jellyfish Audio pegs look to be the closest match but, even so, they may still require a little adaptation in order to fit nicely. It would appear that the original pegs aren’t being produced or copied anywhere anymore.
If you’re already planning on trying them out perhaps you could be so kind as to post the results? Would be much appreciated.
 
Hifibythekg said:
If you’re already planning on trying them out perhaps you could be so kind as to post the results?
Click to expand...
The grille mounting hardware arrived today by post from East Worthing:

1_jelly-pegs.jpg

Quality is not bad. Pegs and soft sockets are uniformly injection moulded with tight parting lines showing no undue flashing.

As feared, it turns out they are a bit smaller in diameter than stock Minimus-7W pegs:

2_peg-2-peg.jpg

Inserted into the stock grille, they freely move side to side before meeting the inner wall.

3_peg-fit.jpg

Looked at the possibility of inserting the soft sockets into original grille cavities for a proper mate with the new pegs. Original grille sockets would have to drilled out. That would appear to leave the walls much too thin for structural integrity.

Haven't given up just yet. In the morning I'll see if o-rings can be found with suitable OD to fit inside the grille cavities, and ID for a snug fit around the pegs. Things would look more promising if such o-rings exist.



 
Last edited:
Thanks for posting a detailed reply with photos. Very helpful. So close a match yet still requiring some modification, a real shame. O rings would be neat, did you manage to source any or come up with another solution?
 
Hifibythekg said:
O rings would be neat, did you manage to source any or come up with another solution?
Click to expand...
Chased my tail for a bit searching metric based dimensions. Then found SAE dimensions much easier to match to aerospace standard (AS568B) o-ring size dash codes. Closest match looks like code "-106," 3/16" ID x 3/8" OD. Ordered some from McMaster-Carr -- should arrive soon. Then we'll see if they offer a viable solution.

If the fit is good, a strong flexible adhesive like E6000 or Shoe Goo may work to secure them in the grille sockets:

4_grille-socket_mod.png

Might also be worth exploring having new pegs CNC turned from Delrin rod. That would yield stock replicas requiring no rework of the grille sockets. I've downloaded CAD software from an online specialist that fabricates such things. Could be a slow learning curve before I'm proficient enough to work the CAD -- not as quick as I used to be (and wasn't that fast then, either ;) ).
 
Well done Stuart, either route I think you’re going to overcome this very particular challenge and achieve an elegant solution. See how the ‘O’ rings work in practice and take it from there.. Good luck and look forward to hearing.
 
You must log in or register to reply here.
Back
Top Bottom