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Old 17th August 2007, 10:10 PM   #1
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Default Minimus 7 refurberations...

Ok, Minimus 7 owners, I know you are legion; what do you do when you have dead singles?

I occasionally buy Minimus 7's at the local flea market etc. So I have a few 'perfect' singles and many not so perfect examples. What I do not have is a 'real' pair: I've opened some and so far no two working samples I've tried have identical components...

So if I wanted to do a complete refurb what would be the ideal set of components to wedge into the cute little cast case...External passive x-over with solid unobtanium cabling? Active with internal chip amp? no xover with single fullrange driver?

Has anyone attempted to shoehorn one of the recent 'super' 4" woofers (fr/wr125, TB, HiVi etc) into them?

There has to be a good project here, the darn things are everywhere for almost no money, in all states of function.

I need a 'nice' pair of mini monitors for my workbench (got an active 8" sub below), so what are your thoughts gentle-people.

Stuart
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Old 17th August 2007, 10:42 PM   #2
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I think that the pair of Minimus I purchased in 1988 were probably left by one of the offspring in their dorm rooms.

Adding to the "Legendary Speaker" thread, here is the second mod -- the R and C values of the Zobel have to be determined empirically:
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Old 17th August 2007, 11:03 PM   #3
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The original has a blocking cap on the woofer?

mike
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Old 17th August 2007, 11:10 PM   #4
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Default a great start but...

these xovers assume you have a matched pair to mod...

So the schematics you show are for 2 levels of modification, each being slightly more elaborate than the last. Can you really run the tweeter in the last case with no high pass filter?

I think the 'original' schematic has the woofer(ls) and tweeter(tw) reversed, at least in my speakers the woofer is run wide open, the tweeter has a cap...

I'm lazy enough to balk at hand matching each individual speakers crossover components to match otherwise different drivers...

for instance: Several of the woofers I've looked at vary in the texture of the paper cone, some clearly being smoother and lighter or darker in colour...they are not the same, certainly batch, perhaps vendor. My guess is they are not going to make good playmates, I'd rather go with a new pair of woofers that start off closer to each other in basic character...but which woofer?

The tweeters superficially seem closer, though the details on the flange change and that makes me think these vary somewhat too...

A while ago I found a woofer in Radio Shack that had similar front mounting dimensions, but with a magnet etc that was half the size of that on the minimus woofer (and with 1/5th power handling), so clearly it's not a reasonable replacement...

Anyone got ideas where one finds the oem part? It can't be expensive, the speakers used to be on sale for $40 a pair

Does no-one actually fix these things? Do all the broken ones end up in the dumpster?

Stuart
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Old 18th August 2007, 12:06 AM   #5
kevinkr is offline kevinkr  United States
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I have a matched pair of these, one was dropped and the woofer magnet shifted slightly - no rubs and sounds ok.. (Maybe I will look for some 4" drivers at some point. Maybe TB? They're also late 1980's vintage. I've had tons of them, this is the last pair I still have and probably the oldest.

The original x-over was second order on the tweeter and direct to the woofer, the input connections shown in jackinnj drawing just need to be shifted to the left of the cap.. (True at least on these and the three or so other pairs I have owned - all mid to late 1980's versions.)

I varnished the woofer dust cap and cone and modified the cross-over so it was basically a series arrangement as seen on some English x-over. Seemed to sound better. Never did measure, now that I can I probably won't..

The box is definitely worth messing with, its pretty solid for its size and cost.
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Old 18th August 2007, 04:07 AM   #6
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Quote:
A while ago I found a woofer in Radio Shack that had similar front mounting dimensions, but with a magnet etc that was half the size of that on the minimus woofer (and with 1/5th power handling), so clearly it's not a reasonable replacement...
That must be the woofer i put in my Modded Philco 222k speakers.
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Old 18th August 2007, 04:27 AM   #7
Nanook is offline Nanook  Canada
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Default an interesting "refurb"

I saw a pair of small Foster fullrangers in a similar sized Foster branded enclosures (similar to the Minimus 7 enclosures), maybe similar to the FE87 , might be interesting.

do some volume and port measurements, then lets see what they were originally tuned to.

Then let's see what we can shoe horn into the enclosures.

Unless someone has complete specs on the particular ones you have. could be quite nice, as I think the enclosures were pretty well built.
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Old 18th August 2007, 04:48 PM   #8
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Hi

Recently had the tweeter burn out on one of a
pair of Minimus 7s. Have various ideas or fantasies
about upgrading the pair and just using the
original case In the pictures you have TB319s,
TB517s, Axon 4S1 and a 3inch Jaycar Response
All seem to need some sort of surgery on the
case to fit. I really like the Vifa tweeter
but there could be others. Have not thought
out the crossover. Might biamp with active
crossover to experiment a bit. Could make
the case think it is bigger using Perlite??
Some picture of my thoughts.

Regards

AnthonyPT

(Check out Moray James's thread on active charcoal and Perlite)
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Old 18th August 2007, 05:17 PM   #9
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The TangBand W4-616S fits nicely into the minimus enclosure, it's parameters even suit the ported versions . I have a pair of W4-616S which I plan to match with a pair of D26NC55's in a minimus size enclosure. Come to think of it, I could use some enclosures if someone is willing to part with a dead pair.

See my thread about a previous minimus upgrade for some ideas.

The D26NC55 can be disassembled and clamped to the original minimus faceplate with a small amount of effort. The only issue I have with it is that it did not go low enough to match to my original woofers. I had the later Pro X7's and the woofer is not the same as that in the original minimus. My Pro X7 woofers had a huge dip from 2K to 4K and a huge peak at 5K.

Apex Jr. has some tweeters which apparently are a very close fit to the original faceplate. Scroll down to the Sonance tweeters here: http://www.apexjr.com/speakerstuff.html

If there is any interest in the D26NC55 / TB W4-616S idea, I will move it up in the queue and post some more info on them.

EDIT: I just noticed that Zaph has a new minimonitor design ! The drivers he has selected should drop right in to a minimus enclosure. You would have to go sealed more than likely, but it should match well to a subwoofer. The rear mount Aura tweeter could be fit into the faceplate of the minimus tweeter with a slight enlarging of the hole on the faceplate.

Best Regards,
David
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Old 18th August 2007, 09:27 PM   #10
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If the original Woofer is still in good working order I'd do the baby oil trick to restore its color and use it. The Mini 7 used pretty darn good 4 inchers to begin with. I'd do a cosmetic refurb of the Woofer then redesign the crossover and replace the tweeter. I've seen a few tweets that fit the OEM front plate with little to no modification.
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