Help refurbishing/fixing Vintage Infinity EMIT Speakers

[Allweather]

Hi everybody, I am trying to refurbish a pair of ~1970s Infinity EMIT speakers for my father as they were/are the first and only hi-fi speakers he ever bought for himself and I want to give them back to him as a working set.

When driven they sound surprisingly good but the left speaker will make a loud POP noise and stop producing any audio above a medium volume. The only way I can get it to produce audio again is to turn off the amp and turn it on again. Any ideas whats going on? I was thinking the crossover but maybe its the woofer? Any ideas how I would go about fixing that? The speaker mounts are proprietary as far as I can tell using 4 mounting points around the speaker.

 

[goodolpg]

Well, we can't talk about specific value here, but those are valuable.
They are Infinitesimals with the well regarded Watkins dual voice coil (see the 4 wires to the woofer dust cap?) 5" mid woofer.
So good for you for wanting to get them working correctly for your father. The top picture shows the EMIT diaphragm looks to be in very good condition as all the traces appear to be flat and not loosened, can't tell about the "other" one in the lower ppicture of the pair. Having rubber mid/woof surrounds those don't rot like foam so chances are fairly good they are still wired as intended from the factory. Infintys with foam surrounds sometimes end up with issues after a refoam job due to being mis-wired during reassembly but these appear to be unmolested.
I'm wondering if it's an amp issue and not a speaker issue.
More pictures, in particular the back might be helpful.
They're actually fairly simple as there's one or two switches (depending on if they are .1 or .2 models) and a fuse besides the internal crossover components.

Here's a website with some helpful info about them. http://www.infinity-classics.de/models/Reference-series-1978-klein/index-Reference-klein.htm

 

[Allweather]

Thanks for the reply! The amp is known good (and new) and works at ear-deafening levels with a variety of hard-to-drive speakers so I dont think thats the issue. The issue is localized to one specific speaker even when switched between channels. Here is a pic of the back, I checked the fuses and they dont look like they have been broken or have issues.

 

[StimpyWan]

Those are Infinitesimal II's. But, the top and bottom end caps are missing. As such, the speakers are no longer properly sealed. That could be affecting performance. Older capacitors in there too, so a recap might be in order as well.

 

[Allweather]

Those are Infinitesimal II's. But, the top and bottom end caps are missing. As such, the speakers are no longer properly sealed. That could be affecting performance. Older capacitors in there too, so a recap might be in order as well.

I removed the wooden caps and grills to clean and refinish them, the wood was a bit water stained and its finish was flaking off.

 

[StimpyWan]

I removed the wooden caps and grills to clean and refinish them, the wood was a bit water stained and its finish was flaking off.

Oh good. I wish I still had a set of end caps and grills for my Infinitesimal III's.

 

[goodolpg]

Agreed, version .2. Infinitesimals.
An easy test would be to swap the fuse in the properly functioning speaker into the one that is acting weird and see if the issue goes away. 1 1/4 Amp fuses used to be hard (might still be, haven't looked in years) to find but using a 1 Amp fuse will work and blow quicker if there is an issue.
There is some putty where the EMIT wires go through the cabinet from the crossover, I actually had an issue with one EMIT doing strange things after a I refinished and recapped my .2 Infinitesimals. Some of the putty got into the push on terminals, took a bit to figure that one out.
I've also found that hardware/lumberyard "screen moulding" fits into the grooves on each side of the metal grille that are retained by 3 screws each.. 1/4" X 1". Oak preferred as that was OEM but pine with similar grain to oak works fine. Handy tip if those wood trim pieces are broken or missing.
I sprayed/rattle can painted the metal grilles and screws, easy peasy to refinish those.

Do you have a multi meter?
Might want to check the ohm readings on the EMITs and midwoofs, Mark the wires, make a diagram, take pictures, whatever it takes to make sure the wires go back on where they should. Clean the contour and tweeter controls with Deoxit.

 

[swechsler]

First thing I'd do is swap the left and right speakers. Disconnect the wires at the speaker ends. This way we can rule out one thing at a time.

Assuming the problem follows the speaker, the next thing I'd do is remove the woofer and tweeter and measure them with an ohmmeter.

 

[goodolpg]

Those are Infinitesimal II's. But, the top and bottom end caps are missing. As such, the speakers are no longer properly sealed. That could be affecting performance. Older capacitors in there too, so a recap might be in order as well.

And they're on ebay listed as .1's... I guess he knows more than we do...
At least we tried to help the new guy.

 

[Allweather]

No no, it was super appreciated, I copied a previous sellers listing details and forgot to change the model. I really appreciate everybody’s help here. I tried to keep the project secret but my dad found me sanding the wood down and didn’t want them so they are listed on eBay now. I would love to keep them but I just don’t know enough about speaker repair to do anything with them. As I said in the listing the one speaker repair guy in town wanted to gut the drivers.

 

[Allweather]

Here’s how the wood refinishing came out, that part I know a bit about at least.