Hello. I have a pair of Mission 753's that were donated to me by my son. I have enjoyed them for the last 2 years as a significant improvement to my listening despite having a cheap amplifier. My amp is an old Cambridge 30watt thing with a bi-wire feature which how iy is connected to the speakers.
Over the last month one speaker had begun to distort, then it increasingly started to fade in and out volume wise and recently it has began to play up and then drop out for extended periods. I have swapped it over at the amp output and the fault remains and the good speaker stays good when swapped.
Help to work out what is going on and how remedy this would be appreciated.
Thanks.
Over the last month one speaker had begun to distort, then it increasingly started to fade in and out volume wise and recently it has began to play up and then drop out for extended periods. I have swapped it over at the amp output and the fault remains and the good speaker stays good when swapped.
Help to work out what is going on and how remedy this would be appreciated.
Thanks.
Sounds like one of the following. Poor external or internal connection at the binding posts, or poor internal connection between the crossover components behind the binding post plate (dry solder joint?), or a faling component in the crossover, possibly a capacitor. An internal inspection seems to be needed.
Take some good pics of the crossover and components. The solder side may not be visible without removing it from the binding post plate, but you may not be able to see the soldered connections and state of the soldering without taking it apart.
Thanks for the input. I think someone (son denies it was him) tried to connect the speaker inputs together internally through a toggle switch. This whole loom just just came off with the slightest touch. The speaker is alive.
Given the age of the crossovers I would like to renew the components rather than wait till they fail, I presume upgrades and mods to the stock circuit will be on here some where.
Given the age of the crossovers I would like to renew the components rather than wait till they fail, I presume upgrades and mods to the stock circuit will be on here some where.
That sounds somewhwat bizzare 😉 but good that the speaker is ok. Upgrading the crossover components can bring sonme improvements to the performance of the speaker but it can be a bit of a hit and miss mission (no pun intended) Is there any aspect of the speakers performance/voicing that you think needs improvement?
I find them a massive upgrade from my previous speakers, so there isn't really anything I dislike at the moment as everything sounds better than it ever has. I'm just thinking to renew the crossovers now while I have spare time rather than wait for a malfunction. But I think I'll have a go at making a new one.
Firstly, am I correct in assuming that your 753 is NOT the Freedom version?
The 753 has a fairly complicated crossover network, but the only components that would require to be renewed for future proofing purposes are the electrolytic capacitors.
If you are feeling flush, Willys Hifi supply a complete crossover rebuild: https://willys-hifi.com/products/mission-753-crossover-rebuild
P.S. You have not yet included your country of residence, which is useful information when it comes to suggesting replacement components.
The 753 has a fairly complicated crossover network, but the only components that would require to be renewed for future proofing purposes are the electrolytic capacitors.
If you are feeling flush, Willys Hifi supply a complete crossover rebuild: https://willys-hifi.com/products/mission-753-crossover-rebuild
P.S. You have not yet included your country of residence, which is useful information when it comes to suggesting replacement components.
Last edited:
Here's pertinent information from the Willys Hifi site:
"The Mission 753 crossover features general purpose polarised electrolytic capacitors wired back to back (in series) as a cost and size cutting exercise.
Featuring point to point wiring and a wealth of hot melt adhesive, the crossover build quality is typical of the era - it is quite tricky to work on for beginners as it is in the form of a split section PCB sandwich connected by brass bus bars."
That's my emphasis on the 'beginners' statement!
Note that those "back to back" polarised electrolytic capacitors would nowadays be replaced by an appropriate value bipolar electrolytic capacitor.
"The Mission 753 crossover features general purpose polarised electrolytic capacitors wired back to back (in series) as a cost and size cutting exercise.
Featuring point to point wiring and a wealth of hot melt adhesive, the crossover build quality is typical of the era - it is quite tricky to work on for beginners as it is in the form of a split section PCB sandwich connected by brass bus bars."
That's my emphasis on the 'beginners' statement!
Note that those "back to back" polarised electrolytic capacitors would nowadays be replaced by an appropriate value bipolar electrolytic capacitor.
Last edited: