Distortion in one speaker because of the screw??

[alexdecker]

I have a weird issue with my Wurlitzer. I haven't seen this on anything before.

I thought one of my speakers was broken, so wanted to switch them tonight and see if it was the speaker or the amp.

I then found out that the speaker only distorts when one particular screw is attaching the speaker to the lid (200A model).

Have any of you guys ever noticed something like that?

Is there any way to isolate a screw, or how would I go about solving something like this?

– Alex

[pianotuner steveo]

What I personally would do is remove the speaker to be sure there is nothing touching the cone that doesn't belong in there, then reattach by putting the screws in a different order, one at a time. Sometimes a drop of hot glue or CA glue on the nut of the offending screw  will help.

[OZDOC]

It's not entirely clear from your description - but if that final screw causes the pressed metal chassis of the speaker to distort this can cause the speaker coil to rub on the inside of the magnet gap.
The moulded ABS panel that the speakers mount to is not particularly flat.
When you fasten the speakers to the ABS panel you must not distort the speaker frame.
You may need a gasket to seat the speaker on.

[funkylaundry]

Also, it's not something as simple as the screw being loose and rattling when it resonates with the speaker vibrations? In that case you need to secure the screw. Buzzing and rattling from loose components is quite common and could be mistaken for a distorting speaker.

[alexdecker]

Thanks for your replies everybody.

I made sure that the screws were secured tighly. In retrospect, the distortion actually got a little worse after that.

The explanation that tightning the screws to much kind of warped the speaker cone a bit seems plausible to me. Nonetheless, after loosening the screws and readjusting them, the distortion left, which was nice :-)

- Alex

[funkylaundry]

Hi Alex ...I just realize that we know each other from when I was considering buying your '71 Suitcase. I still sometimes regret I did not go with that

Zaki