There's an obvious answer to the following question, but I thought it might be
a good idea to see if someone had an even better idea.

I'm restoring a pair of the original Advent speakers. These were made in late
'75 and have the first version of the crossover. The crossover and amplifier
terminals are on a board that's glued to a hole cut in the back of the
speaker. Other than breaking the board loose, there's no way to remove it.

All parts will be upgraded. The original iron-core inductors will be replaced
with Alpha-Core 14ga air-core inductors. I doubt this will have much of an
effect on the sound -- but the inductors can't saturate at high levels.

http://www.goertzaudio.com/contents/...Inductors.html

There are two obvious ways to install them. One is to simply glue them to the
board. The larger one weighs 1 pound, 7 ounces (!!!) so it has to be glued
down tightly. The smaller one has to be mounted on its "side", so it's at
right angles to the larger. This doesn't provide much surface area for a tight
attachment.

There's no guarantee even the best adhesive won't eventually give way. I don't
want to have to open the speaker in a few years and re-glue the inductors.

The other obvious way to mount them is with locking cable ties passed through
small holes drilled in the crossover board. This alters the speaker in a
visible way -- but it's hardly a big deal.

Any thoughts? Am I missing something obvious?

Thanks in advance.


"We already know the answers -- we just haven't asked the right questions."
-- Edwin Land

In article ,
William Sommerwerck wrote:

There are two obvious ways to install them. One is to simply glue them to the
board. The larger one weighs 1 pound, 7 ounces (!!!) so it has to be glued
down tightly. The smaller one has to be mounted on its "side", so it's at
right angles to the larger. This doesn't provide much surface area for a tight
attachment.

There's no guarantee even the best adhesive won't eventually give way. I don't
want to have to open the speaker in a few years and re-glue the inductors.

The other obvious way to mount them is with locking cable ties passed through
small holes drilled in the crossover board. This alters the speaker in a
visible way -- but it's hardly a big deal.

Any thoughts? Am I missing something obvious?

Yeah, I wouldn't trust glue to hold that much mass safely... and it
would be hellish to remove if you ever needed to swap them out again.

How about making some endplates out of good-quality plywood, between
which you would sandwich the inductors? For the one mounted end-on to
the board, make 'em circular discs, and run a non-magnetic screw down
through the center into the mounting board. For the one mounted
side-on, you could make the endplates with flanges which would then be
screwed to the crossover board.

"David Platt" wrote in message ...

How about making some endplates out of good-quality plywood,
between which you would sandwich the inductors?

Not a bad idea. I'll give it some thought.

"William Sommerwerck" wrote in
:

There's an obvious answer to the following question, but I thought it
might be a good idea to see if someone had an even better idea.

I'm restoring a pair of the original Advent speakers. These were made
in late '75 and have the first version of the crossover. The crossover
and amplifier terminals are on a board that's glued to a hole cut in
the back of the speaker. Other than breaking the board loose, there's
no way to remove it.

All parts will be upgraded. The original iron-core inductors will be
replaced with Alpha-Core 14ga air-core inductors. I doubt this will
have much of an effect on the sound -- but the inductors can't
saturate at high levels.

http://www.goertzaudio.com/contents/...Inductors.html

There are two obvious ways to install them. One is to simply glue them
to the board. The larger one weighs 1 pound, 7 ounces (!!!) so it has
to be glued down tightly. The smaller one has to be mounted on its
"side", so it's at right angles to the larger. This doesn't provide
much surface area for a tight attachment.

There's no guarantee even the best adhesive won't eventually give way.
I don't want to have to open the speaker in a few years and re-glue
the inductors.

The other obvious way to mount them is with locking cable ties passed
through small holes drilled in the crossover board. This alters the
speaker in a visible way -- but it's hardly a big deal.

Any thoughts? Am I missing something obvious?

Thanks in advance.

I would be cautious about coupling between the coils. The core material
in the originals would have helped to keep the flux contained. Mounting
them at right angles is good, but the further apart (within reason), the
better.

I haven't messed with crossover inductors, but I've seen small signal
audio frequency filters do odd things when the inductors were butted up
in parallel. These were unshielded ferrite core solenoid inductors (the
ones that look like big carbon composition resistors).

Doug White

On 23/10/2013 23:22, William Sommerwerck wrote:
There's an obvious answer to the following question, but I thought it
might be a good idea to see if someone had an even better idea.

I'm restoring a pair of the original Advent speakers. These were made in
late '75 and have the first version of the crossover. The crossover and
amplifier terminals are on a board that's glued to a hole cut in the
back of the speaker. Other than breaking the board loose, there's no way
to remove it.

All parts will be upgraded. The original iron-core inductors will be
replaced with Alpha-Core 14ga air-core inductors. I doubt this will have
much of an effect on the sound -- but the inductors can't saturate at
high levels.

http://www.goertzaudio.com/contents/...Inductors.html

There are two obvious ways to install them. One is to simply glue them
to the board. The larger one weighs 1 pound, 7 ounces (!!!) so it has to
be glued down tightly. The smaller one has to be mounted on its "side",
so it's at right angles to the larger. This doesn't provide much surface
area for a tight attachment.

There's no guarantee even the best adhesive won't eventually give way. I
don't want to have to open the speaker in a few years and re-glue the
inductors.

The other obvious way to mount them is with locking cable ties passed
through small holes drilled in the crossover board. This alters the
speaker in a visible way -- but it's hardly a big deal.

Any thoughts? Am I missing something obvious?

Thanks in advance.


"We already know the answers -- we just haven't asked the right questions."
-- Edwin Land

Would the Xovers ever get hotter than 50 or 60 degree C ?
If never then hot melt glue. Heat the coils and the other surface with
hot air gun at a low setting and then apply hotmelt glue, forms a much
stronger bond than if applied to unheated surfaces. If you have to
remove them later then just apply hot air and leverage

"N_Cook" wrote in message ...

Would the Xovers ever get hotter than 50 or 60 degree C?

They'd barely rise above ambient.

If never then hot melt glue. Heat the coils and the other surface with hot
air gun at a low setting and then apply hotmelt glue, forms a much stronger
bond than if applied to unheated surfaces. If you have to remove them later
then just apply hot air and leverage.

I'll consider that. The manufacturer recommends using hot-melt adhesives, so
it should be okay.