problem with one Philips ad 12202/M8

[indie roehre]

Hi
I just mounted a pair of philips fullrange ad12202 in only test open baffles. one plays loud and fine. the other plays calm. half as loud as the other, some distortion when bass plays. oh my god. I think it is no good omen:confused:. does anybody know what it can be? cable fits fine.

Regards from Germany

Knut

[Reid Malenfant]

Hi Knut, you're right - it doesn't sound good :rolleyes:

Do you have any way of measuring the DC resistance of the voicecoils? It sounds to me as though you may have a damaged one on the lower volume driver. obviously it's not open circuit as you wouldn't hear a thing, there may well be some kind of short circuit though, possibly due to overheating? :scratch:

This may well be the source of the distortion if some of the voicecoil is scrapping on the pole piece or top plate. Check that they both move freely & there is no rubbing. Actually it might be as simple as that thinking about it, there may be no voicecoil fault other than this!

If that's the case try rotating the driver through 180 degrees to allow the thing to sag in the opposite direction ;)

[indie roehre]

looks not good
just saw it..
http://i1120.photobucket.com/albums/l481/indieroehre/DSCN5474.jpg

[Reid Malenfant]

Ouch, yes i think that voicecoil is rubbing due to mis-alignment :(

[Welder]

:eek:

[indie roehre]

is there something I can do, open it or put it back in right position? or bring them to a expert?

[Reid Malenfant]

The magnet assembly is breaking away from the chassis... I'd suggest some kind of expert rather than a DIY job in all honesty. For starters the driver basket must be warped to some extent & hoping to re-align it by yourself could possibly be done but i wouldn't take a bet on it.

You are more likely to make other rivets loose & get the whole thing even more out of alignment. In all honesty you may need to replace the whole driver as to align things & even hopefully get the magnetic assembly back in position will (done properly) involve removing the cone, spider & voicecoil :doh:

Not good :(

[Welder]

It looks fixable from the pics, but it wont be straightforward.
I would have thought given the gap that you would need to strip the cone and coil and spider out of the basket. Then rebuild the basket and reassemble the cone etc.
Its not a particularly difficult job providing you have a steady hand and patience.
The problem will be after repairing the basket to magnet damage, getting the spider aligned correctly.
Its probably not something to undertake if you've not re-coned a driver before.
Wembly loudspeakers will sort it.


Ah, Mark FTW!
what he said more or less.

[indie roehre]

thanks a lot.I found two experts for recone speakers here in Hannover. atfter work I will visit them. I will let you know if we can rescue the speakers.

Regards

Knut

[indie roehre]

the speaker expert managed it. he put spider back in right position with very high pressure. I had to look away. but voice coil was free after this . he tested fullrange with sinus tone. he was satisfied with his work. now it must dry he said for 24hours before set in in the baffle.

then we will see or hear.

regards

Knut

[Reid Malenfant]

Nice one, i can't say i was expecting a solution so quickly :)

Hope it works out for you Knut :cool: