Lowther distorting..... help please?

[jakruby]

hi there,
i have a pair of lowther acoustas with pm6a drivers. this morning i discover that one is now distorting terribly on bass. it is working though. could the coil be rubbing in the gap? if anyone can help/advise i will be most appreciative.

[chris661]

How loud were you playing last night?

[jakruby]

i don't think i was hammering it. i have another pair of acoustas and i don't think i was playing as loud as i have before. before you ask; one of the other pair went intermittent - the solder joint on the cone seems to have gone it will play if you touch the joint but stops when you let go - i cannot get it to solder i think i maybe I need an aluminum iron and solder. but back to the other lowther i was hoping that it was just rubbing inside the gap, after all if i had blown it it would not work at all?

[chris661]

Depends on how you've blown it. You could well be right, and the coil is rubbing. But if so, what was the cause of said problem?

Can you describe the distortion - this is a very wide-ranging word.

[tinitus]

Older Lowthers chassis could be adjusted to center the voicecoil
Dont know about the new ones
But when you say #acoustas# I guess they are quite old
How old are the drivers
xperts may know how to improve with reconing
Do you have any pictures, might help
btw, have you ensured its not something else, by say connecting to other amp channel

[jakruby]

distortion is in the bass. all bass lines sound very, very fuzzy. mid and treble dont appear affected. i must say that the driver was not distorting when i got it...well certainly not as bad as now which is extremely obvious. i have attached pictures of the driver.

the guy i bought them from says that they where reconed at some stage. but it appears to me that the surround is facing the wrong way...is it? all the other lowthers that i have seen have a inverted surround when viewed from the front

[chris661]

Sounds like you're right, then. You may be able to adjust this, or it may be a recone job.

[jakruby]

recone sounds expensive. there are no lowther dealers here in sa anymore. i was hoping there was something i could do myself. does anyone know about centering the voice coils? i cant seem to find much on the web so far.

[limono]

Originally Posted by jakruby

recone sounds expensive. there are no lowther dealers here in sa anymore. i was hoping there was something i could do myself. does anyone know about centering the voice coils? i cant seem to find much on the web so far.

Lowther America website used to have description of alignment process .I don't see it now but I'm sure it's there somewhere. Contact Ion and he'll help you out . It's not that difficult and I aligned my DX4 without any problem. You just cut a few strips of tick paper , lose the cone basket, stick the paper shims carefuly in the VC gap between center pole and VC coil around the perimeter so they "force" symetric position of VC assy in the gap, tight the screws, carefuly remove paper shims and check pushing gently cone if there is any rubbing . Good luck!

[mp9]

+1, can't say i did it with a lowther but have with other vintage small gap drivers.

btw lowthers have had a long reputation as notorious for this. referenced in sound practices issue 12, "lowther: another opinion marc s. wauters pp. 20 - 25

not sure if i can put the following here and please remove if i can't. another thing mentioned was a scratch shortly after use due to the former's inner winding being off of the vc. in the gap.

i suggest getting a copy, it's a very informative read telling which older models to avoid and why, problems and fixes, etc.