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MPX Adapters -- Please Skool Me?

ukfan4sure!

ukfan4sure!

Expert Smoke Releaser
I'm looking to get a MPX adapter for my P-22 as I'd like to hear FM in Stereo. It would add a warmth and depth to the music I would hope.

Maybe the MPX-100? Or is it the MPX-200?

For my chassis, which one(s) would I need to search for?

Thanks in advance!
 
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ANY external MPX'er will work. MPX-200 is more suited for the consoles as it doesn't have the external aesthetics (front panel, etc) of the MPX-100. BUT the 200 is rare as hen's teeth compared to the 100. like I said, pretty much any brand MPX will work. I use a Sherwood M3ax in my 610 consolette / 560 companion (equivalent to a 60 Custom electra.)
 
Solid state ones are probably easier and cheaper to find too.

http://fmmpx.com/

for example

I have one salvaged from a junked early 70s Pioneer to mate with my Hoffman console. I have one from a Fisher 500b built into a case with a power supply that serves as my general use MPX decoder. Its ugly but functional.
 
I can vouch for the solid state MPX decoder as described at http://fmmpx.com/ . I just built one and tried it out in a Fisher FM-100 tuner. It's pretty amazing to hear FM stations in LiViNg sTeReO coming from a 1959 mono FM tuner. It works beautifully.

HOWEVER

It is my understanding that the designer/builder of this project is no longer offering these for sale since LM4500 ICs are no longer being manufactured, and he ran out of a good source for these. I bought two of the last boards he had and am very happy with the one I have built. I hope to build the second one very soon.

I was going to try using a modified MPX-65 in the FM-100, but as luck would have it, I have four MPX-65 chassis and none of them work correctly. (Note: Not trying to hijack the thread at all. If I decide to try to get my MPX-65 chassis going again, I'll start a separate thread on that subject. Not a priority right now.)

So - The fmmpx.com board has proven to be a quick and easy solution to adding FM Stereo to a mono tuner.
 
mrphilco said:
I can vouch for the solid state MPX decoder as described at http://fmmpx.com/ . I just built one and tried it out in a Fisher FM-100 tuner. It's pretty amazing to hear FM stations in LiViNg sTeReO coming from a 1959 mono FM tuner. It works beautifully.

HOWEVER

It is my understanding that the designer/builder of this project is no longer offering these for sale since LM4500 ICs are no longer being manufactured, and he ran out of a good source for these. I bought two of the last boards he had and am very happy with the one I have built. I hope to build the second one very soon.

I was going to try using a modified MPX-65 in the FM-100, but as luck would have it, I have four MPX-65 chassis and none of them work correctly. (Note: Not trying to hijack the thread at all. If I decide to try to get my MPX-65 chassis going again, I'll start a separate thread on that subject. Not a priority right now.)

So - The fmmpx.com board has proven to be a quick and easy solution to adding FM Stereo to a mono tuner.
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Hey, thanks. I had no idea that they might be used universally, in multiple applications. I'm getting this old console whipped back into shape. Got my Dual 1009SK template board cut tonight and plan on re-installing it tomorrow.
 
If you're interested, you can read about my experience building and installing the fmmpx.com decoder into my Fisher FM-100 here:

https://ronsradios.com/2020/10/08/making-the-fisher-fm-100-tuner-truly-stereophonic/

An external MPX decoder will be easier to add and you can power it with a wall wart of the proper voltage. Plus, as Fred pointed out, you still have some choices in which chip you use when you build one.

ukfan4sure, we're practically neighbors as Louisville is just over an hour away from here.
 
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mrphilco said:
If you're interested, you can read about my experience building and installing the fmmpx.com decoder into my Fisher FM-100 here:

https://ronsradios.com/2020/10/08/making-the-fisher-fm-100-tuner-truly-stereophonic/

An external MPX decoder will be easier to add and you can power it with a wall wart of the proper voltage. Plus, as Fred pointed out, you still have some choices in which chip you use when you build one.

ukfan4sure, we're practically neighbors as Louisville is just over an hour away from here.
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Oh, I know you very well, Ron. I have your 1928 to 1942 book. I didn't know you were just an hour away. I have 5 old Philco's sitting around here, two with shadow dials, my favorite.
 
Thank you. I began to feel that I had gone as far as I could with Philco a few years ago, so I began migrating over to Fisher (and 1936-37 RCA radios). The folks here are the best.
 
mrphilco said:
Thank you. I began to feel that I had gone as far as I could with Philco a few years ago, so I began migrating over to Fisher (and 1936-37 RCA radios). The folks here are the best.
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I have a RCA 143. It's a beautiful set I picked up by chasing a couple as they left an antique store trying to sell it. The guy offered them $50 for it and they said no way. I followed them and asked what they'd take. So, $80 it was! :)
 
UKfan - Wow, you "stole" that 143!

Hi Kent! Thank you - but the Philco Phorum isn't my site. True, I used to be the site owner, but stepped down because of the Big C. Now I own a little site/blog - ronsradios.com . And I enjoy being here in the AK Fisher forum.
 
mrphilco said:
UKfan - Wow, you "stole" that 143!

Hi Kent! Thank you - but the Philco Phorum isn't my site. True, I used to be the site owner, but stepped down because of the Big C. Now I own a little site/blog - ronsradios.com . And I enjoy being here in the AK Fisher forum.
Click to expand...

I own my late Grandmother's Philco-Ford console from 1967, and own a 1966 Fisher Custom Electra console. And yes, plan on visiting ronsradios.com. And the AK Fisher Forum is a favorite of mine, and so helpful regarding getting my Custom Electra functioning well again.
 
As a new owner of an HFT-90 Eico FM Mono receiver, I'm on the hunt for an FM Multiplex decoder for my setup. I might have a few dozen LM4500's around here. I hoard chips.
 
An external MPX adapter will work acceptably with the HFT-90, but like all FM tuners manufactured before the FCC approved the GE-Zenith multiplex format, it does not have a sufficiently wide enough response in the discriminator transformer to deliver optimum stereo separation in external MPX units connected to it.

I have an HFT-90 I use on my service bench that I modified to use a Fisher Wide Band ratio detector transformer so I can use it in testing repaired MPX adapters, and it now works perfectly for that need.

One of the best external MPX adapters is the Scott 335, and the Fisher MPX 200 if you can find them, which are both equally good.

Dave
 
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