Hi All,
My first post so please be kind.
Have wanted a pair of Mission 770 for a long time I picked up a pair of 770S's for the sum on £33. I was aware that the woodwork will need some TLC but I'm a liitle concerned regarding wiring and speakers fitted. It does seem that the orginal drivers were replaced long ago. Each speaker is fitted with Vifa M21WJ-09-08 and I beleive that the tweeters are SEAS(?) 25in H377. I cant certain but I have a feeling that the crossover circuitry (can anyone help here as i dont have a circuit diagram for this) has been rewired(?).
I've attached some pictures. Are these rubbish or repairable?? I intend to drive these with an old A&R A60 Cambridge (an early one) which I am going to recap very soon.
Thanks
Rob
https://www.flickr.com/photos/65588479@N08/shares/U916Y3
My first post so please be kind.
Have wanted a pair of Mission 770 for a long time I picked up a pair of 770S's for the sum on £33. I was aware that the woodwork will need some TLC but I'm a liitle concerned regarding wiring and speakers fitted. It does seem that the orginal drivers were replaced long ago. Each speaker is fitted with Vifa M21WJ-09-08 and I beleive that the tweeters are SEAS(?) 25in H377. I cant certain but I have a feeling that the crossover circuitry (can anyone help here as i dont have a circuit diagram for this) has been rewired(?).
I've attached some pictures. Are these rubbish or repairable?? I intend to drive these with an old A&R A60 Cambridge (an early one) which I am going to recap very soon.
Thanks
Rob
https://www.flickr.com/photos/65588479@N08/shares/U916Y3
It's kind of odd that you bought speakers you wanted but with different drivers. 🙂 What's the point? 😀
So how do they sound to you?
If you want to investigate what you have, at the very least, try getting some measurements. You could use the Dayton smart-phone mic with Room EQ Wizard. That will be the best place to start.
Best,
Erik
So how do they sound to you?
If you want to investigate what you have, at the very least, try getting some measurements. You could use the Dayton smart-phone mic with Room EQ Wizard. That will be the best place to start.
Best,
Erik
Hi Erik,
I picked these Missions up with the speakers I have mentioned alreaded fitted. It appears that someone has made a 'botch' job of them. I'm seriously thinking that its not worth the hassle of doing anything with them but selling them as spares.
Best Regards
Rob
I picked these Missions up with the speakers I have mentioned alreaded fitted. It appears that someone has made a 'botch' job of them. I'm seriously thinking that its not worth the hassle of doing anything with them but selling them as spares.
Best Regards
Rob
I read that you bought them with different drives. That I understood completely. What I wasn't so sure of is WHY you would do that if you were looking to buy a pair of Mission 770s, but that's kind of irrelevant.
It's impossible to tell you how they are with pictures, but the tweeters don't look original, however the crossover kind of does. It has that air of cheap construction only original manufacturers can add. 😀 Of course you could part them out, selling the drivers on e-bay.
If you want to know how much work it would take to make them sound better, that would take measurements and at least a quality assessment from you.
Best,
Erik
It's impossible to tell you how they are with pictures, but the tweeters don't look original, however the crossover kind of does. It has that air of cheap construction only original manufacturers can add. 😀 Of course you could part them out, selling the drivers on e-bay.
If you want to know how much work it would take to make them sound better, that would take measurements and at least a quality assessment from you.
Best,
Erik
Woofer is definately not the OEM one. Other than that hard to tell. But that is not a bad woofer and sure the speakers can be tweaked to good performance if you have the patience.
Hi Bill,
Taking it for granted that the wont be the same as the original set up, how can I tweak these to be usable in your opinion. The bottom line is that they only cost me £33.
Many thanks
Rob
Taking it for granted that the wont be the same as the original set up, how can I tweak these to be usable in your opinion. The bottom line is that they only cost me £33.
Many thanks
Rob
Well step one is listen to them and see how they are 'out the box'
Step 2 is to measure them. If you are up for it I can lend you a UMIK-1 and plenty of people here who can lead you through the testing. Once you know the response curve we can look at tweaks.
If you can find out the cabinet dimensions (internal volume) and port size the T-S parameter are available for the vifa M21-WJ so we can also calculate a few things for pointers.
Step 2 is to measure them. If you are up for it I can lend you a UMIK-1 and plenty of people here who can lead you through the testing. Once you know the response curve we can look at tweaks.
If you can find out the cabinet dimensions (internal volume) and port size the T-S parameter are available for the vifa M21-WJ so we can also calculate a few things for pointers.
No need to loan a mic, $13 for the Dayton phone mic. 🙂
You could probably get useful enough plots out of Audiotool or whatever the iPhone equivalent is.
Best,
Erik
You could probably get useful enough plots out of Audiotool or whatever the iPhone equivalent is.
Best,
Erik
Hi Erik & Bill,
I've ordered a Dayton phone mike from Amazon in the UK at a very good price.
I can reassembe these and give them a try as Bill has suggested. Do you have any thoughts with regard to the crossover you should I use 'as is'?
Many thanks for your help.
Regards
Rob
I've ordered a Dayton phone mike from Amazon in the UK at a very good price.
I can reassembe these and give them a try as Bill has suggested. Do you have any thoughts with regard to the crossover you should I use 'as is'?
Many thanks for your help.
Regards
Rob
Measure as is and see what you have. Then you can work out what needs changing. There is a chance the previous owner lucked out and chose a close match. Two chances!
Hi Steve,
Many thanks for the info - please note that the tweeter is 6 ohm according to the label.
Best Regards
Rob
Many thanks for the info - please note that the tweeter is 6 ohm according to the label.
Best Regards
Rob
Yup, this one. Standard stuff. 91dB. SEAS current models are little different.
http://www.seas.no/images/stories/vintage/pdfdataheet/h0337_25tn.pdf
It's fine. Nothing changes.
All,
I have been in contact with Wilmslow Audio - they have recommended that Vifa P21WO-20-08 are a suitable replacement driver for these and dont recommend the fitted driver as it only has a 25mm coil diameter so the bass output will not be as good.
Regards
Rob
I have been in contact with Wilmslow Audio - they have recommended that Vifa P21WO-20-08 are a suitable replacement driver for these and dont recommend the fitted driver as it only has a 25mm coil diameter so the bass output will not be as good.
Regards
Rob
Well, the voice coil diameter of the Vifa M21WJ-09-08 actually is 32 mm and has nothing to do with bass output. The Thiele-Small parameters of the Vifa P21WO-20-08 are almost identical and so is the bass output. I know you are disappointed because of the replacement drivers, but they are fine and there's absolutely no need to buy something new unless they do not work properly anymore.
Hi Dissi,
I think I really need to reassemble them and give them a try. Thanks for your encouraging post.
Regards
Rob
I think I really need to reassemble them and give them a try. Thanks for your encouraging post.
Regards
Rob
Sorry to hear they mislead you like that. I would find a place somewhere close and have them measure them for you. The good folks here can help a lot more once they know what you're starting with.