Mission 720 bass unit repair

[Mark25]

All,
I have to source some replacement bass units for some 1982 model mission 720 speakers, they have rotted out.

All advice/ideas/success stories people would like to share are very welcome.

TIA Mark

[ashok]

Contact Mission directly at UK.
They will help you if they have stock of those drivers.
They are VERY helpful.
I just bought some replacement drivers for my Mission speaker.

Alternatively you can buy replacement surrounds ( preferably rubber ) from the web and use them to fix the driver. Driver parameters will change. But we did this to some Dynaudio 12 inch woofers whose foam surround rotted in less than 2 years. So we bought some rubber ones ( bigger than we needed ) and then cut it to size and glued it on. The unit works fine and actually looks better than with the original foam surround. Surround was bought in Germany.
Cheers.

[Mark25]

Thanks for that ashok,

I think we'll try and go with the replacement surround first, does anybody know of any surround suppliers in the UK?

TIA mark

[Mark25]

I've come up with:

http://www.ampaholics.org.uk/VINTAGE%20SPEAKERS.htm

http://www.concert-systems.com/service/index.html

LOUD SOUND URL! http://www.rmjloudspeakes.co.uk/

http://www.cld-dist.com/

http://www.djequipment.co.uk/

for the UK, but;

http://newfoam.com/kits.asp

will supply from the states do a kit for $35-40 delivered to the UK.

Now i have two follow up questions;

1. is that price approaching that of a replacement driver ? (which i don't seem to be able to source readilly)

2. I've heard that older speakers cannot handle too much power, as voice coil glue technology, etc was not so good a few years back. So was wondering if a modern equivalent driver may have other advantages over a repaired original? which would justify extra cost, although if TB, etc do something suitable that would prob work out cheaper than the newfoam kit anyway, i guess

TIA Mark

[Mark25]

right, we're probably going for the new surround option because we feel:

Mission relacement drivers will be NOS, so the surround of the 'new' driver will be as old as the rotten one we have.

OEM drivers are not 'generally', good value for money.

better value can be had from replacement drivers, although no options have been suggested yet i.e. NO $35 - $40 replacement drivers have yet to grace this thread..........let alone ones that have good recommendation in terms of sound quality.

please tell us we're wrong b4 we opt for the new 'newfoam' surrounds.....

cheers Mark

[BassAwdyO]

Tell me a little bit about the drivers and maybe I can suggest a replacement.

Important things are....

Size
Sensitivity
Bandwidth

[Mark25]

thanks for the offer BassAwdyO, but we'd rather get something 'tried and tested', in this instance if poss..........

[ashok]

Mark, can you give me the diameter of the edge of the cone and also the inner edge of the frame of the speaker ( where the foam was originally glued). I might be able to find a low cost rubber surround for it in our local market. I have someone who is going back to London late next month. He can mail it to you locally.
They don't cost much here. Maybe $2 for a pair !
But the size has to be right.
Let me know if you are interested.
Cheers,
Ashok.

[Greg3333]

Hi

I'm the owner of these speakers that Mark is helping me renovate. Unfortunately, Newfoam have advised that Mission used unusual sizes and they can't supply a surround which would match.

Ashok, thanks for your kind offer. The details of the surround are as follows:

Outer diameter of original surround: 9 3/4"
Inner diameter of original surround: 6 1/2"

Inner diameter of speaker frame: 8 3/4"
Outer diameter of speaker cone: 7 1/8"

The cone doesn't have a flat section, it's a constant taper to the dust caps. If you could have a look to see if there's anything that would match it would be very much appreciated.

BassAwdyO, just in case you can find a replacement driver which you think would be suitable, there is some info regarding the original specifications on the Mission website at http://www.mission.co.uk/archive/Org...10_720_730.pdf

Thanks in advance

Greg

[Greg3333]

Metric conversions just in case anyone wants them:

Outer diameter of original surround: 248mm
Inner diameter of original surround: 165mm

Inner diameter of speaker frame: 222mm
Outer diameter of speaker cone: 181mm