The Amp Garage

A Weber 15F150 (30W) which had recently developed a rubbing coil after experiencing a heat overload. Uprated it to 50W coil. Took me 5 hours all up. Quite stoked with the result so far.

Tested it with one of my home-brewed t-bolts this morning. Sounds pretty damn good if I say so myself.

If contemplating buying the 15F150, I recommend getting the 50W version. Kapton formers last longer than Nomex, (which is what is suppled with the 30W version).

Was that yours on Facebook I saw today? Looked really cool. I am a bit scared of the idea of reconing or doing new voice coils ;P

~Phil

Yeah on the tube amp builders page. It was daunting but fun, if you plan it right, take your time, and do just about everything the way described in this video by Mr 'Uncle Doug'.

https://youtu.be/K3Opxstw0Aw

I've watched all of his videos, that one included

Sent from my HTC 10 using Tapatalk

Uncle Doug sure is a great resource. I would pay to have his videos compiled in a dvd.

Congratulations on your recone.
Kapton, nomex and paper all sound a bit different.
I usually prefer paper even though the ability to dissipate heat is the lowest of the three.

billyz wrote: ↑Wed Mar 01, 2017 2:31 pm ...
Kapton, nomex and paper all sound a bit different.
I usually prefer paper even though the ability to dissipate heat is the lowest of the three.

yes, seeing what happened to the Nomex former in this vintage-spec speaker was a lesson for me too. The coil itself wasn't burned or shorted or twisted - it was 'merely' the bubbles in the Nomex that had caused the 'failure mode'. Heat build-up had caused a chemical reaction within the Nomex former, which had produced 'outgas' build up, which became trapped within the Nomex (because the surface of the Nomex was effectively sealed). This produced bubbles in the former, which produced friction around the pole piece because of the tight air gap - see pics. Moral of the story? If designing vintage spec, use vintage former material, or kapton.

The replacement coil I put in was rated for 50W and has a kapton former. The air gap is tight (for the shim I used a piece of writing paper cut to just under 2 x the length of the perimeter of the pole piece, and it was a snug fit - see blue paper shim in pic below)

Doesn't Weber still recone their speakers for $25?

Yes, they will recone their own speakers for $25 US plus shipping and handling. If you live in NZ like tubeswell, it might be worth having a go yourself.

Indeed, the recone parts were US$23.70 and the shipping was US$41.90, which altogether was NZ$92.35! Probably would have been close to NZ$180 to ship a repair speaker back and forth

Good call. I didn't notice the loction. i'm sure the shipping is a risk also.

Anyway it was a good learning experience and fun. I definitely feel confident about doing this again.

I've been playing around with reconing lately, it's an extremely fun hobby as it isn't expensive and can get very interesting results. It's also not very difficult. Parts are relatively cheap if you buy them from Weber or learn to reuse parts removed from a bad speaker (you can reuse spiders and dust caps), and the adhesives are easy to get once you figure out what they are. Uncle Doug's videos are super helpful, as is going on Plexi Palace and read every post from DunxB (a former Celestion speaker designer that loved to share very detailed info). You can also learn a lot by looking very carefully at speaker construction, and buying blown speakers and carefully taking them apart (little things like most modern Celestions use variations of 1777 or 444 cones as well as a variation of two magnet types/baskets, and many Celestion stock cones have eyelets staked in them).

IMHO reconing is much like making a very simple acoustic guitar; each part and adhesive has a profound effect on tone, as well as the interactions between the parts and glues. Stiffer glues have a different sound than softer ones, and dust caps/coil former material have a profound influence on speaker tone. Each speaker is a particular mix of a few different spider/cone/cap/coil selections, assembled in specific ways with specific adhesives and techniques, and that mix makes for the tone you get.

Personally I'm obsessed with cloning the tone of a Celestion G12-65, am about to have a tool made so I can make a fiberglass coil as that appears to be a big part of the tone. You can get really close with Weber parts (nomex coils), along with liberal use of fabric softener on the cone and doping under the cap, but the tone has an upper treble edge that perhaps is inherent to a nomex coil that may not exist for fiberglass.