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Mission 770s hack job on crossover

When i recaped mine i looked everywhere for information and couldnt find anything. I think StimpyWan is right. March them up and see how they sound. Failing that i think your only other option is to build new crossovers from scratch.
Not something i would be able to do though.
 
Both crossovers match. It's the red circles are what I suspect was done to both speakers. I was going to pull the parts which that I suspected were added. I don't see how it would damage it.
 
One of the sets of eBay crossovers (not mine), was selling really cheap. It might make for a good platform, to rebuild a matched set? I'd reuse the inductors, and buy new caps. Falcon would be good for that, as their caps are supposed to be voiced to match classic British speakers. They're the go to shop for KEF recaps.
 
Audi0 said:
Both crossovers match. It's the red circles are what I suspect was done to both speakers. I was going to pull the parts which that I suspected were added. I don't see how it would damage it.
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If the crossovers match in both speakers, then why disassemble them? Do the speakers currently sound bad as is? If not, I really don't see the reason to undo the mods?
 
Mission got back to me as I contacted them yesterday. They seem to have the crossover schematic. Let' see if they send it.
 
StimpyWan said:
If the crossovers match in both speakers, then why disassemble them? Do the speakers currently sound bad as is? If not, I really don't see the reason to undo the mods?
Click to expand...

Was not impressed by them in there current state.

This is my closest guess to the factory crossover. It' the high pass? That I'm unsure of.
 

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Audi0 said:
Mission got back to me as I contacted them yesterday. They seem to have the crossover schematic. Let' see if they send it.
Click to expand...

Good deal. If they do you should post it to AKDB and maybe HFE so the next person who has a question on these can get info.
 
The capacitor's look to be original to me. May be some of the components came loose from the board and had to be stuck back in place ?
 
Capacitors look original to me as well. It' just those 2 resistors and and inductor which have new white glue smeared over them. The original parts have ageing yellowish glue. No signs of old glue on them at all even when lifted. So I suspected they were added.
 
I just found this in diyaudio
Crossover Mission 770S.JPG
The thread is called mission 770S rubbish or repairable?
Hope this helps.
Looks like they added a cap as well
 
I just saw that 'rubbish' thread. Unfortunately, it was not much help, as the members were discussing creating a crossover for non-stock drivers. And if it helps, these are the original drivers:

Saire ribbed 8" polycone woofer
Seas 1" dome tweeter (H253)
 
It seems the 770S speakers were designed as a more 'affordable', budget version of the 770. One of the differences mentioned between the crossovers, were the lack of resistors, in the 770S. The resistors were there to balance the driver output to each other. To balance the tweeters. So, I have to wonder if 770S owners modded their crossovers, in an attempt to mimic the sound of the 770?

Also, all of this Mission talk makes me miss my 780 Argonauts. They were stolen during a move! :eek:

Not mine, but mine looked like these.
9847.jpg
 
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This is my original 770 crossover. Not a lot in there.
 

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Here's a picture. If you need me to I can trace the crossover this weekend. The film cap is marked 10/60 on one side and STC PMT/2R on the other. The non-polar capacitors is 8UF/60volt.

Tony
 

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tonebells said:
Here's a picture. If you need me to I can trace the crossover this weekend.

Tony
Click to expand...

Can you trace it out? I can start rearranging to what you have shown with the avaible
components. I just need the value of the 3 resistors. Look what else I found thx to the pictures this contact point was cut. It attaches to the other side of the inductor.

20171121_205641.jpg


U can kinda see what was done comparing the 2 crossovers. Still hoping mission sends there scan of the crossover.

20171121_205147.jpg
 
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I made this quick schematic from those 2 pics. The only thing I need info on is the bypass under the inductor. How is it wired in circuit? Whats The value of the resistor? Do you think the parallel resistors are supposed to be wired to the bypass and not before the inductor?

Look at the changes. The big red circle is the area im unsure of.
20171122_105130.jpg
 
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