EV 12L Speaker Issue?

grappagreen

So, decided to fire up the old 80's rack today for a bit of torture fun!

Heard a horrible distortion out of one channel and started the 'chase the cables through the rack' process. Couldn't find anything. Swapped the speaker output cables out of the power amp and the distortion was plainly coming from the speaker/cab. Took it apart and ensured everything was tight (which it was). Lifted the speaker and still the same;

https://www.youtube.com/shorts/1GUWVZPRZyg

Obviously had to use a nice augmented triad to really get things going

Presume I have a problem Houston..

Regards,

Si

ecc83

That sounds like a voice coil rubbing on a pole piece, not electronic distortion to me.

Dave.

grappagreen

ecc83 said:

That sounds like a voice coil rubbing on a pole piece, not electronic distortion to me.

Dave.

Thanks Dave.

I’ve got the speaker out so is there anything I can look for?

Si

ecc83

grappagreen said:

ecc83 said:

That sounds like a voice coil rubbing on a pole piece, not electronic distortion to me.

Dave.

Thanks Dave.

I’ve got the speaker out so is there anything I can look for?

Si

Gently grip the cone with each thumb and finger and push and pull it a mm or so, you will probably both hear and feel the coil rubbing. Sometimes torquing down one fixing bolt more than another whilst listening to quiet music through it can effect a temporary repair.

Still! Good time to convince Sig Oth you need a new speaker!

Dave.

grappagreen

ecc83 said:

grappagreen said:

ecc83 said:

That sounds like a voice coil rubbing on a pole piece, not electronic distortion to me.

Dave.

Thanks Dave.

I’ve got the speaker out so is there anything I can look for?

Si

Gently grip the cone with each thumb and finger and push and pull it a mm or so, you will probably both hear and feel the coil rubbing. Sometimes torquing down one fixing bolt more than another whilst listening to quiet music through it can effect a temporary repair.

Still! Good time to convince Sig Oth you need a new speaker!

Dave.

Thanks.. yes, sounds like sandpaper

Better get the credit card out.. least these things are cheap - not!

Si

ecc83

grappagreen said:

ecc83 said:

grappagreen said:

ecc83 said:

That sounds like a voice coil rubbing on a pole piece, not electronic distortion to me.

Dave.

Thanks Dave.

I’ve got the speaker out so is there anything I can look for?

Si

Gently grip the cone with each thumb and finger and push and pull it a mm or so, you will probably both hear and feel the coil rubbing. Sometimes torquing down one fixing bolt more than another whilst listening to quiet music through it can effect a temporary repair.

Still! Good time to convince Sig Oth you need a new speaker!

Dave.

Thanks.. yes, sounds like sandpaper

Better get the credit card out.. least these things are cheap - not!

Si

"I love it when a plan comes together!"

GP.

ICBM

Sounds like it’s been dropped and the magnet has shifted relative to the voice coil. This is a risk with very heavy magnets like the EV, even though the cast frame is much more rigid than a pressed steel one. Unfortunately it’s usually very hard to fix, unless the magnet can be unbolted from the frame - eg many vintage alnico speakers, Peavey Black Widow and some others.

grappagreen

ICBM said:

Sounds like it’s been dropped and the magnet has shifted relative to the voice coil. This is a risk with very heavy magnets like the EV, even though the cast frame is much more rigid than a pressed steel one. Unfortunately it’s usually very hard to fix, unless the magnet can be unbolted from the frame - eg many vintage alnico speakers, Peavey Black Widow and some others.

Thanks.

I note the EV (It’s actually a Mesa Black Shadow) has bolts for the magnet so I suppose I have nothing to lose by having a play with my socket set!

Appreciate the inputs.

Si

grappagreen

Except of course for the fact that they aren’t metric bolts.. arghh

Si

ICBM

grappagreen said:

I note the EV (It’s actually a Mesa Black Shadow) has bolts for the magnet so I suppose I have nothing to lose by having a play with my socket set!

On the underside of the frame? I’d forgotten.

Yes, just loosen them slightly and see if you can jiggle the magnet into a position where the coil doesn’t rub, then tighten them again carefully. Nothing to lose at all, and possible you’ll be able to fix it.

grappagreen said:

Except of course for the fact that they aren’t metric bolts.. arghh

Of course not! It wouldn’t be that easy .

ecc83

Your sockets should only be imperial/AF now post Brexit!

Yes, have a go but the VC might have gone 'out of round' in which case you will fiddle forever and get nowhere. AND we are talking shifts of 0.1mm!

Does anyone do re-coning anymore?

Dave.

grappagreen

I've arranged to send the speaker to Roy @ Recones who can hopefully repair it!

Thanks again all..

Si