Realistic Minimus 1 speaker needs new woofer
 

Hello everyone, I had found a couple of years ago at Goodwill a set of Realistic Minumus 1 Speakers and I was using those as my work bench test speakers because of their small compact size.

I accidentally blew out the woofer on one of them while I was working on a stereo receiver that had a bad amplifier channel in it that I thought I had fixed and it turned out it wasn't and it passed DC into the woofer and blew out the speaker.

Fortunately the tweeter was unharmed strangely enough, just the woofer was damaged, and its an oddball size of 4 1/2" square and Parts Express doesn't have anything in stock that's in my price range, and I can't think of anywhere else to look.

Anyone know where else I could look for the speaker I need?

Any help would be appreciated in this matter.

Tweeter saved by the capacitor(s) in the crossover that blocked the DC.

I'd probably start looking on ebay by the brand, model and part number on the back of the woofer.

If they are beater test speakers (if not you probably should get something else to do testing with) then any matching pair of 8ohm woofers that fit should do.

By the way if you don't trust an amp or don't need to hear it for a test keep an eye out for 4-8ohm power resistors rated around 10-50W.... speakers are usually assumed to be a resistive load in design practice, and all amps should be happy to drive a resistor of the same rating as a speaker.

I've seen and read about dummy load resistors being used when servicing stereo equipment, specifically if rebiasing an amplifier in a power amp or a stereo receiver, and parts express has some dummy load resistors rated at 8 ohms 50 watts for sale on their website but they're $30 a pop. :sigh:

That's the problem the woofer doesn't have a brand name, just a part number and Japan written the back.

Is your 4 1/2" measurement side to side of frame, or diagonally between mounting holes?

It's side to side, and also what the original specs of the speakers said when I looked them up online.

I made up some dummy loads out of multiple sand resistors in parallel. Was very affordable using yaego resistors from mouser. See attached pic.

For a replacement woofer, the right way would be to measure thiele small parameters of remaining woofer, and then order closest thing you can find. For a test bench speaker, just find whatever physically fits. Old TV sets often have speakers that size. I have some out of a trinitron console which would probably fit perfect.

Most SS amps are around 20RMS watts (alot of 60s and newer amps use peak watts and other BS measurement units so marketing can claim a 20W amp is actually 150W when it ain't) you only need 50W if you have a 50W amp that you want/need to test at full power.....
As long as you keep the volume low you can hook a 5W dummy load to a 100W amp without issue...(well if the amp is damaged and a ton of DC is leaking into the speaker terminals that exceeds the rating of the resistor and you don't catch it quick you could loose a resistor). A good protection for dummy loads is to put a drop of water or spit or oil or something that will sizzle if the resistor overheats... that should warn you it is about to cook before it does.

If by chance you can squeeze these 4 -3/4" in you can have the pair for postage. 5" diagonal mounting holes. Came out of a 90's Zenith console TV.


https://live.staticflickr.com/65535/...547a4022_z.jpg

https://live.staticflickr.com/65535/...b50fd22e_z.jpg

Hey Sorry I never replied until now, I didn't realize anyone was still replying to this thread (I apparently forgot to subscribe to this thread).

Those speakers look like they might work, what is their Power Rating? The original speakers in these Realistic Speakers were rated at 15 Watts max.