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Minimus 77 reborn

Printed From: Graham Slee Hifi System Components
Category: And the rest
Forum Name: Transducers, Speakers, Mics...
Forum Description: Interested in bi-amping, tri-amping, crossovers, speaker design, miking techniques, EQ - the list goes on
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=4338
Printed Date: 20 Apr 2024 at 7:57am
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Topic: Minimus 77 reborn
Posted By: Fatmangolf
Subject: Minimus 77 reborn
Date Posted: 01 Oct 2017 at 8:34pm
I needed a small light speaker for my AV system and had to return the second hand centre speaker I bought thanks to a previous owner cooking the two mid/woofers. Then I remembered the Realistic Minimus 77 speaker that has lived in my loft space for 20 years. It was my centre speaker in the early 1990's but had been superceded by several proper centres so consigned to long term storage. My loft is literally a roof space with the usual insulation at floor level. Not the best environment for foam surrounds so I had started to investigate replacement surrounds to be glued in if the original ones had perished or fell part apart when used.

If you haven't had or seen a Minimus 7 or 77, it was a small Tandy (Radio Shack in US) two way speaker with an aluminium enclosure, ported in the 7 from 1980's and a slightly larger closed box in the 77 from the 1990's. Study box, black in my case and repaintable in white for use near my ceiling. So up the ladder, balance on the joists, look in some boxes, and found the speaker. Downstairs for clean up and test listening connected to my left hand Proprius. The speaker sounded a little rough but not rattling or spitting dust/foam powder through the grill.

After that I opened it up and found it was really a one and a half way, not two-way. The woofer is run full range and there is a CL high pass filter (5uF and 0.4mH) to protect the tweeter. I concluded the roughness heard earlier was probably woofer cone breaking up and decided to add a LPF of 1mH and 2uH. I will replace the old 4.7uF capacitor at the same time as it measured 6.4uF. I went online to see if this speaker had been modified by others and the answer was yes, many people have already done this mod  for the '7' and for the same reasons.

So I have ordered the extra parts and some bituminised foam liner from a well known speaker company beginning with "W." When they come I will use the rebuild as an opportunity to sand and prime the aluminium box and speaker grill in white.

I may do before and after shots if anyone is interested?



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Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.



Replies:
Posted By: Fatmangolf
Date Posted: 07 Oct 2017 at 11:12pm
Still waiting for the parts...


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Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Fatmangolf
Date Posted: 12 Oct 2017 at 9:01pm
I had an e mail saying the speaker parts have been dispatched today. Hope they arrive tomorrow so I can modify and repaint my Minimus 77 over the weekend!


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Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Fatmangolf
Date Posted: 06 Nov 2017 at 6:38pm
The parts did arrive but I've been very busy and not had a chance to do the rebuild yet.



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Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.



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