With so little info available on these, I thought that I would document the restoration of the ADC MS-650 foam cabinet speakers.
I'm the original owner and have had these since ~1979-80. I purchased these from the ADC rep when working in the Jafco Stereo dept. They were selling these at a discount to people in sales to get the word out.
I'm the original owner and have had these since ~1979-80. I purchased these from the ADC rep when working in the Jafco Stereo dept. They were selling these at a discount to people in sales to get the word out.
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Many years ago I lent these to a friend. They came back with blown drivers. I learned first hand how an amp that puts out less Watts than the speakers are rated for, can fry the drivers when driven at full volume. I wasn't there and can only imagine the level of clipping occurring.
What I didn't know was that the crossover components also get very hot. In these pics you can see how the polyfill melted on the resistors, and coils. The Lpad melted internally and was not functional. I replaced the wolfers with these NLA units from Parts Express and bypassed the Lpad, wiring it directly to the tweeter. The Goldwood GW-6PC worked well in these ~0.2cf boxes.
Parts Express Goldwood Woofer
What I didn't know was that the crossover components also get very hot. In these pics you can see how the polyfill melted on the resistors, and coils. The Lpad melted internally and was not functional. I replaced the wolfers with these NLA units from Parts Express and bypassed the Lpad, wiring it directly to the tweeter. The Goldwood GW-6PC worked well in these ~0.2cf boxes.
Parts Express Goldwood Woofer
Attachments
There is now a third thread open. I suggest that everyone comment over there: https://www.diyaudio.com/community/...am-i-dealing-with-hybrid.422705/#post-7903421
Finished rebuilding the crossovers. I used upgraded components where possible. The 25 Ohm variable resistor works very well.
The following components were used:
5.1 Ohm 10w resistor
3.0 Ohm 10w resistor
25 uF 250v capacitor
32 uF 160v capacitor (10 uF and 22 uF in parallel)
.45 mH air core inductor
25 Ohm 5w variable resistor
5-way binding posts
Stuffed them with a moderate amount of polyester fiberfill and added butyl rubber metalized tape while the backs were off.
They sound as I remember the originals did. Good sounds from a small package. I am pleased with the result.
The following components were used:
5.1 Ohm 10w resistor
3.0 Ohm 10w resistor
25 uF 250v capacitor
32 uF 160v capacitor (10 uF and 22 uF in parallel)
.45 mH air core inductor
25 Ohm 5w variable resistor
5-way binding posts
Stuffed them with a moderate amount of polyester fiberfill and added butyl rubber metalized tape while the backs were off.
They sound as I remember the originals did. Good sounds from a small package. I am pleased with the result.
