My First Reconing Experience

[Zer09]

A couple years ago I came across a 2x12 Avatar cab for sale for $80. I had no need for it but at that price... The cab had a pair of 12" alnico speakers in it. A quick search showed they were Heppners pulled from an old Hammond. Reviews were mixed. More guessing than anything. They sat for about a year or so until I finally got around to hooking the cab up to my Deluxe and I really liked them but the bottom end was lacking. I finally decided that they'd be the perfect opportunity to try my hand at reconing. They were never going to leave my house as they were anyway. So I ordered the parts from Weber. $12 total for each speaker. There are no kits for Heppner so it was mix and match and mostly driven by the voice coil size. The Heppners had 1.5" aluminum, 16 ohm voice coils. I replaced them with 1.5", 8 ohm Nomex (25 watt). This was a surprise to me. Everything I read said not to use these speaker at more than 5-10 watts. I was unable to blow them when I tried just before the recone. The bass sounded worse at high volume but that was cone related. When tried to cut out the cones and the surrounds just basically crumbled even with a new razor.

The voice coil size gave me no real choice of cone. It was a C12N cone which I thought may be too heavy. The spider size was an exact match. The shortest voice coil height was about 1/8" taller than the original so there is a bit more coming through the front of the cone. The C12N cone turned out to be a bit lighter and thinner than the originals. I did the recones earlier this week and gave them a go yesterday. I was amazed how good they sound. The bottom end is PERFECT. That amp was too boomy with the C12N I had in there. No harshness, no brittleness. Just warm alnico/tweed tone. $24 for 2 speakers plus shipping and an hour or 2 of work, mostly removing old glue. Definitely worth several times the effort and cost. The biggest PITA in the whole process I thought was soldering the tinsel and VC leads together. I thought I was doing a terrible job but when I looked at some of my professionally done speakers they looked the same. Just hidden by black glue.

[riz]

Cool! I've always wanted to try that.

[Zer09]

Speaker Exchange | Recone Instructions- Unassembled

Me too but I had absolutely no experience with it and i was afraid to screw up a good pair of speakers. I went into this expecting the worst, hoping for the best. I had no clue how mixing these parts would work. I was expecting buzzes or rubbing voice coils. When everything turned out to be so simple and straight forward I was really surprised by the results. I followed step-by-step instructions at the link above. I'm actually already planning my next pair...a pair of early 70's Utahs I have with aluminum dust caps. The speakers are in great shape but I hate the sound that aluminum dust caps impart and they are so big I don't know if I could find a bigger replacement. So I paid $19 for them with the intention to recone. With things like this the toughest part for me is having the patience to let the glues dry overnight. I was dying to try them.

[J M Fahey]

Congratulations !!
You did a good job.
I make my own speakers, from scratch, so I know very well what you are doing.
They came out good (and will stay so) because you:
a) took your time, didn't rush , and
b) you left them alone to dry for a long time.
The *worst* you can do is "hurry" them.
The oldest and most respected speaker Factory in Argentina (now defunct thanks to cheap imports) , which followed "Altec Lansing rules", since they built them under licence for ages, had a fixed repair delivery time of 15 days.
No, they weren't *that* overloaded; they repaired the speaker you left same or next day ,,,, and let it sit for 2 weeks on some shelves, without pulling the shims until the end.
Speakers lasted forever (unles power blown, of course).

[Zer09]

Thanks JM. The next pair I do I will give at least a few days. These had essentially 2 days. The glue I used for the cone to VC and spider to VC was a 2 part epoxy and I know that some of those take a week or more to fully cure. It was hard to resist that temptation because I wanted to know if I did anything wrong with the first before I began the second. But my thinking was if I tried them too soon how would I know if I did something wrong in the assembly or if I hadn't let it sit long enough? Better safe than sorry I guess. It's not something I will do regularly but it's nice to know you can do it if you have to.

[olddawg]

I was always told that a major problem with re-coning speakers is that you never know if the magnets have lost their strength. I know that major re- reconers degauss the magnets so that they can be efficiently cleaned then re-gauss them before the final re-coning process. Is this a major concern? How would you test the magnet to know it is still strong enough?

[Zer09]

I actually did some research on that and the info I found said alnico magnets that are abused can be expected to lose 1-3% per decade. Per decade. But they sounded good before the recone so I didn't worry about it.

[J M Fahey]

Very simplified answer:
"ceramics last forever", *unless* you do something gross, such as stacking speaker frames with magnets actually touching each other or similar abuse.
Alnicos are *very* easy to demagnetize: for the same reason posted above or, say, letting it stick to a working transformer , small displacements within the frame or even strong knocks.
If for any reason you pull an alnico from its frame and then replace it, it dies; a ceramic fully pulled and then reseated keeps 80% or more of its power.
That's why alnicos often come with "keeping bars" , meant to protect them from self discharge.