Celestion G12H (pre 69) with coil rub

This is what it sounds like, when cones cry.

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mole-man
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Celestion G12H (pre 69) with coil rub

Post by mole-man » Tue Oct 06, 2015 9:16 am

Hello there,

first time post!

I have an old G12H (25 watt) with coil rub.
The speaker looks to be in immaculate condition which is a shame.
I have contacted Chris of ****** AUDIO in the States (i'm based in the UK) and he said he's backed up for months..
Does anyone know of somebody that could take a look at it for me?

Thanks in advance,
Mole-man.

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Re: Celestion G12H (pre 69) with coil rub

Post by jape88 » Wed Oct 07, 2015 2:56 am

Try http://www.wembleyloudspeaker.com/ there the most popular plus there's another guy up north which I can't think of at the mo.
It's a common thing on old speakers, that doesn't show up until you crank the volume. The down side with a recone is you'll loose the tone of that old and aged pulsonic. I think they charge around 50/60 quid? put that against buying a second reissue G12M at roundabout the same price and it can be a tough call to some imo.
There maybe an off chance it could be stripped down and the gap in the voice coil cleaned but this is delicate work, I tried it myself once on a coil rubbing speaker but with now success unfortunately. Maybe someone with experience could do it? Bygone tones are pretty much on the ball with that stuff although I don't think he offers it as a service?

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Re: Celestion G12H (pre 69) with coil rub

Post by bill bokey » Wed Oct 07, 2015 2:59 am

I think the other guy up north is http://www.bygonetones.com/

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Re: Celestion G12H (pre 69) with coil rub

Post by jape88 » Wed Oct 07, 2015 3:54 pm

This is the guy up north http://www.recones.com/ I spoke to him about some jbls, I didn't use him so I can't vouch for his work though.

Have you checked the spider support? it's common for those to come loose and cause vibration, it's possible to stick the support back down if you've got a steady hand and a syringe type applicator.

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Re: Celestion G12H (pre 69) with coil rub

Post by mole-man » Thu Oct 08, 2015 7:40 am

Hi guys,

Thank you very much for the replies.

The spider seems to be in amazing condition, I can't detect any failing glue or rattles there.

I've contacted Brian at Bygonetones but he doesn't offer that service. He did use to have an article up on his site about how most greenbacks could be saved if the voice coil was cleaned out and re-aligned but that seems to have disappeared...

I really don't want a recone as it defeats the whole point of having the Pulsonic cone!

I've read success stories of people removing the dustcap and playing the speaker facing down to hopefully dislodge some of the debris. Then using solvent on the spider to loosen it and shimming the voice coil to realign it with the pole-piece. Sounds alright in theory i suppose...

thanks again,
Mole-man

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Re: Celestion G12H (pre 69) with coil rub

Post by Scumback Speakers » Thu Oct 08, 2015 9:42 am

You can cut the dust cap off, then use the voice coil alignment shim (or similar thin, flat piece of flexible plastic) to gently push out any debris in the voice coil gap. 50% of the time this works.

The other 50% of the time, the voice coil glues, wire, or coating (Shellac, etc) has disintegrated into a crumbly hard bunch of pieces that keep breaking off and causing more rattles/noises.

I've cleaned speakers out this way before, and they've worked fine...for awhile. But then they start falling apart again, rubbing, and eventually distorting enough so they can't be cleaned up enough, or made round again.

So basically it's a crap shoot on success. I've done this to about 2 dozen speakers now with roughly 1/2 working out well, and the other 1/2 needing a recone, if not right away, fairly soon afterwards.

Remember, all speakers eventually (like car tires) fail and must be replaced.
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Re: Celestion G12H (pre 69) with coil rub

Post by jape88 » Fri Oct 09, 2015 2:55 pm

Jim, is there a way of salvaging a cone from the frame? any solvent that can break down the glue used to adhear to the frame but doesn't damage the edge doping?

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Re: Celestion G12H (pre 69) with coil rub

Post by Scumback Speakers » Fri Oct 09, 2015 6:34 pm

jape88 wrote:Jim, is there a way of salvaging a cone from the frame? any solvent that can break down the glue used to adhear to the frame but doesn't damage the edge doping?
Any solvent I've seen used on cone paper degrades it to some extent. Usually that will depend on the glue used. I've had old and new Celestions use certain glues that just peeled off easily. The only problem is that they still had whatever that glue was still sticking to where you glue the cone down to the frame. So then you'd have to remove that for the next layer of glue you use to stick it back down to the frame. That leads to scraping with a razor/knife/etc. And with that a mistake can be made that tears the cone, or you scrape it too thin, which will potentially let the cone flap against the frame.

And I've seen/read/tried Celestions that were supposedly "saved" only to have the owners come to me for a recone a year or six months later because it went out of round again, or the glue failed.

After all these various operations and variations it became clear there was more labor involved in saving a cone than it usually was worth when they didn't last. As I stated before, I've saved about 1/2 of the ones sent to me, but I've limited it to cutting off the old dust cap (carefully) and cleaning out the voice coil gap of the broken off glues/varnish, then gluing down a new dust cap.

Past that you wind up spending hours trying to get something you've taken apart to line up as well before you used solvent, MDK, acetone, etc on it to disassemble it.

As for saving just cone, and putting a new voice coil in to replace a bad one, that's another tricky fix due to how the wires are mounted. Usually the glue to hold the voice coil to the cone and spider is the strongest glue used (I use four different glues in putting a speaker together) in the whole process, so that's always failed when I've tried it.

Hope that answers your questions.

Jim
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Re: Celestion G12H (pre 69) with coil rub

Post by mapat » Sat Oct 10, 2015 3:14 am

Scumback Speakers wrote: Remember, all speakers eventually (like car tires) fail and must be replaced.
I never really thought about it before you mentioned it Jim, but that makes sense.

Even though it doesn't have "moving parts" a speaker ( obviously ) does move ( alot ) over the course of its lifetime.

Given your extensive experience with speakers, not only your own line, but all the vintage ones you came across in doing all your research, what do you estimate the lifespan of a typical Celestion M-type ( for instance ) speaker to be?

I'd be interested in your answer to this, especially given how many vintage Marshall cabs from the 60s and 70's with their original speakers seem to still be going strong...

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Re: Celestion G12H (pre 69) with coil rub

Post by jape88 » Sat Oct 10, 2015 3:35 am

Scumback Speakers wrote: Hope that answers your questions.

Jim
Thanks Jim.

I'm of the opinion it's hit and miss buying old speakers but as you say it's only a question of time before things wear out.

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Re: Celestion G12H (pre 69) with coil rub

Post by Scumback Speakers » Mon Oct 12, 2015 1:00 pm

mapat: First, you have to consider my experience is based on getting these speakers when they were already 30 years old (started collecting old pre rolas in 1999). Now they're almost 50 years old.

Their life expectancy will be based on how they were treated before they got to you, which is a totally unknown variable, as you can imagine. So there really is no "expected life time" of one of these that's going to be accurate. Sorry, but that's just the reality of speakers made in the 60's, and the multiple owners/abusers/users/players they went through on their way to your cab.

I've got four 60's cabs, and four early 70's cabs now with original pre rolas. I sold five cabs to buy a car three years ago, and some loose pre rolas that weren't in cabs. I got to the point that having 46 4x12's in the demo room was ridiculous. So I sold quite a few to make room. I'm down to about 22 cabs now, including my Scumback replica/loaded cabs. That's easier to move (11 stacks vs 23 stacks) for a client demo.

Hardly anyone asks to hear the 67 stack cuz they don't want to be so shocked they have to offer me stupid money to buy it. And it would be stupidly high you're out of your mind money. Fact is that the M75-PVC's are so close after break in that you'd be silly to spend the extra money just for the cab/mojo/etc unless you were a collector and needed a whole stack to match your old head.

I can tell you the G12M's don't last as long as the G12H30's. That's in part due to the lower power handling, and that the 35 oz medium weight magnet doesn't control the cone movement as effectively as the 50 oz heavy magnet of the G12H. However, they're all going to fail at some point without careful storage, and use. I never run my 1987 Marshall JMP over 8 with a single 4x12 cab, and I use both with a 100w 69 head I have, but it never sees more than 7 on the volume knob. I just don't want to hear "The Sound of Silence" ala Simon & Garfunkel...you know what I mean? :wink:

jape88: Old speakers have always been a crapshoot. You buy 10-20 to get two good ones. You buy 500 and you get around 40-50 excellent ones. Those ratios are based on my buying experiences. The prices for these back in 1999 were $100-150 each. Now they start at $300 and up. I could never afford to do the research, testing and buying I did if I were to do it today. The sample size of good speakers would be way more limited, and my credit card limits would burn up a lot faster. It cost almost six figures to buy the ones I bought up until 2006 that make up my speaker line.

Now that would be an easy $250k to do it all over again IF there were enough decent sounding speakers to choose from. I don't see that happening again.

Ok, enough rambling on about old pre-rolas! I've got 11 orders that came in this morning and I need to get some shipping labels typed in for the clients who ordered.

Hope that answered all of your questions! If not, email me. I've been so busy lately, email is better since I don't hang out on the forums much anymore. Wish I could, but I'm my own worst enemy since the business takes up so much of my time.

Jim
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Re: Celestion G12H (pre 69) with coil rub

Post by jape88 » Tue Oct 13, 2015 2:27 am

Pretty much started collecting same time as you, but not to those amounts!!! I just concentrated on the g12m which is my fave speaker. Yes there were lots of under par speakers and most came with cone rub at volume (although I have to say I have one speaker I have sounds warm with a chime like tone but is crap when the volume is jacked, go figure?) but prices then were low here in the UK before the whole pulsonic boom kicked off, most people didn't know what they had and were keen to get rid of old unbranded cabs like SAI, Kelly etc. so buying wasn't too bad only to find you'd have to toss the speaker. I gave up when the bidding started to get too high to buy without trying.

Would be great to see those old cabs Jim if you ever get a chance to do a snap shot, 8 60/70's cabs in one room ...nice.

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Re: Celestion G12H (pre 69) with coil rub

Post by Scumback Speakers » Tue Oct 13, 2015 9:16 am

Only picture I could find I have already online, jape88. You can see most of them (except the bottoms of some) in this pic.

http://www.scumbackspeakers.com/demoroo ... m10-13.jpg
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