Now I've Done It!!! Recone Info Requested

[toddalin]

Yesterday I purchased the three 2205C baskets at $34 each for my L/C/R. These are to be reconed to go in my L200 cabinets replacing the 130As. I'll have OCS do the recones as they are local to me. In the long run, I decided that it was probably a better idea to buy baskets and have them reconed knowing everything is new and paying an extra ~$50 each, than to trust someone on ebay that says they recently had a set reconed that may turn out to have been umteen years ago with new foams required in the next few years. Also, I worry less about damage just shipping baskets.

My questions are:

From the WinISD, the 2235 cones will provide the best bass response. But, these will require re-foams every 10-15 years. I believe that one step down would be the 2205 cones as originally equipped, at the expense of about 5.5 dB @ 35 Hz. The 2205s do get me about 3.5 dB more than the 130As at 35 hz. Is there a cone between the two (2235/2205) that gives better bass than the 2205, but never needs redoing (i.e., paper or cloth edge)?

I have N1200 x-overs (16 ohm). My horn drivers (LE175s) are 8 ohm. I hope to retain the N1200s (the Yamaha Z9 has an internal digital 31 band eq which should take care of dips at the crossover point). Would it be better to recone these at 8 or 16 ohms? (The old cones were 32 ohms, hence the "C" I believe.) Currently, of the speakers in teh cabinets, two of the 130As are 8 ohm and two are 16 ohm (center channel has two).

At a cost of $45/each, OCS can "recharge" the magnets. Is this usually worth the added expense and how can you tell if it really needs doing?

I was going to hold out for real 2235s, but decided that in the future I may once again want to set a magnetic sensitive device (CRT) on the center channel so opted to stay with alnico. Besides, everyone knows that alnico just "sounds better"?;) Right...

[BooBoo Magoo]

Always recharge an AlNiCo magnetic assembly. Recones cost too much money to waste on an unknown magnetic assembly.

No, AlNiCo doesn't sound better. I stopped using the damn things soon after SFG ferrite became available. For AlNiCo 'done right' buy the 1500AL.

[Zilch]

Do 2235H. Mine have been running 20 years and never refoamed.

I doubt your LE175's are actually 8 Ohms by current standards. Take DCR measurements to verify.

Somebody says they have L200's, I always want to make 4430's out of them, of course. We now have a simple crossover (NL200t3) in both 8- and 16-Ohm versions that'll work with either 2342 or 2344 horns. This opens up the opportunity for retaining vintage 16-Ohm aluminum HF drivers in them, a particularly delicious combo....

[toddalin]

Do 2235H.
Somebody says they have L200's, I always want to make 4430's out of them, of course. We now have a simple crossover (NL200t3) in both 8- and 16-Ohm versions that'll work with either 2342 or 2344 horns. This opens up the opportunity for retaining vintage 16-Ohm aluminum HF drivers in them, a particularly delicious combo....

Tell me about the NL200t3 and your take on recharging the magnets.

Thanks

[BooBoo Magoo]

Yeah Zilch, give him your take on recharging AlNiCo magnets. :)

[Zilch]

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=40&pp=15

Begin at post 590. 16-Ohm version comes in a coupla pages later at posts 619 and 626 et seq.

Waiting for 2342 horns to arrive for final test using 16-Ohm LE85's.

I have some LE175's I could try, but it'd be a bitch gettin' them outta the systems they're in.

I'll look up the first iteration for you now....

Here it is. I built 'em non-biased first. Robh has that pair now for evaluation:

http://audioheritage.org/vbulletin/showthread.php?p=49852&highlight=N200t3#post49852

[Zilch]

Yeah Zilch, give him your take on recharging AlNiCo magnets. :)Test 'em with WT2 and see if they need it.

I've never found any that actually do.... :p

[BooBoo Magoo]

Well, there you have it. Spend $150 on the WT2 and test your three drivers to see if they need remags.

Oldmics? Subwoof? GordonW? pelly3s? Edgewound? Care to add anything?

BTW, why is OCS charging $45 a pop to remag these days? Is it tied to the price of gasoline for their kick start generator or something? :rotfl:

$15 a pop at http://www.greatplainsaudio.com/

[Zilch]

BTW, why is OCS charging $45 a pop to remag these days? Is it tied to the price of gasoline for their kick start generator or something? :rotfl:

$15 a pop at http://www.greatplainsaudio.com/ I consider OCS a gourmet boutique repair facility from their rates. Cheaper local can be just as good without the freight.

Not a lot of choices for remag, tho. I'd probably pay a little more and let the factory do it....

[subwoof]

Well I have only seen a few alnico *cone* structures ( 22XX,K,D,etc) that needed to be remag'ed. And all from bands / sound companies...;)

Since they are pinned together ( and of course WHY didn't JBL do that with the HF drivers??? ), and have a center of gravity that is close to the mounting baffle, I suspect the "shock" issue to be less than the poor 2440's that sat on the end of a long throat and were occasionally "vibrated" right off the stack or truck pack.

Of course you often don't know the history and without a fairly expensive piece of test gear you can't tell if one is bad until it's too late.

It's interesting to note that only the first generation ferrites had mag-frame bolts that went thru the mag ( note: they were the grey painted versions ).

The later ( and current ) ones simply depended on glue strength and sometimes that softened and or seperated off the mag surface resulting in a shift. I have seen this MANY times.

BTW:
If anyone knows a remag facility in the NE, I have (8) 2441's that I would like to have all redone to 100%. Shipping to CA from here is real expensive and JBL's canoga park rate was ( last I checked ) about 58 bucks a pop.

:cheers:

sub

[spkrman57]

8 "2441's"!!!!!


I went to Great Plains for Altec clones as I could not find decent 2441's from a decent source.


Cool!!!


Ron

[edgewound]

Well, there you have it. Spend $150 on the WT2 and test your three drivers to see if they need remags.

Oldmics? Subwoof? GordonW? pelly3s? Edgewound? Care to add anything?

BTW, why is OCS charging $45 a pop to remag these days? Is it tied to the price of gasoline for their kick start generator or something? :rotfl:

$15 a pop at http://www.greatplainsaudio.com/

The flux strength can be tested before remagnetizing, so the expense is not certain. I'd recone as 2235H for the best playback performance. The surround can be sealed with a PVA compound to make them last a few years longer, but longevity mostly depends on what kind atmosphere they're subjected too. Keep them away from UV light especially....like sun through windows. Also, direct blast from heater vents.

[subwoof]

"The flux strength can be tested before remagnetizing, so the expense is not certain. I'd recone as 2235H for the best playback performance. The surround can be sealed with a PVA compound to make them last a few years longer, but longevity mostly depends on what kind atmosphere they're subjected too. Keep them away from UV light especially....like sun through windows. Also, direct blast from heater vents."


Don't forget the errant feline....lost a pair of 2245 surrounds some years ago. Cat soon followed.

If anybody needs a bad mag, I have (1) LE175 and (1) K120. Neither have foilcals.

2 of the 2441's are the meyer variant and need the gap cleaned out of the ferrofluid remains and new diaphrams. Any takers?? I haven't looked at them in 9 years....

sub

[toddalin]

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=40&pp=15

Begin at post 590. 16-Ohm version comes in a coupla pages later at posts 619 and 626 et seq.

Waiting for 2342 horns to arrive for final test using 16-Ohm LE85's.

I have some LE175's I could try, but it'd be a bitch gettin' them outta the systems they're in.

I'll look up the first iteration for you now....

Here it is. I built 'em non-biased first. Robh has that pair now for evaluation:

http://audioheritage.org/vbulletin/showthread.php?
p=49852&highlight=N200t3#post49852

Never recall seeing passive x-overs that use a battery before??? Kind of hard to access in the sealed cabinet isn't it? What is the battery life?

[pelly3s]

Well the on going dicussion of recharging a maginet. if the speaker has been used for traveling professional use i would recommend it. Sometimes it makes a difference, sometimes it doesnt. I have found a 3 to 6 dB increase in some drivers, the biggest increase was in TAD 1601's. I have also found an increase of 3 to 4 dB in some JBL drivers that have been through a war. The best thing to do is if they are going to recone it when they take the kit out tell them you want to see the gauss reading and compair it to JBL orginal specs.

My shop does them for $25 a driver, I will do it for $20 a driver for anyone here.

sub im not too far from you if you wanna send them down

[speakerdave]

Never recall seeing passive x-overs that use a battery before??? Kind of hard to access in the sealed cabinet isn't it? What is the battery life?

Buying batteries for these is not going to break you. It's a good idea to have the crossover accessible anyway.

"Charge coupled" crossover; the work of Greg Timbers at JBL I believe. State of the art in passive crossovers. Now being imitated elsewhere. Think of it as approximately analgous with Class A amplification.

David

[Zilch]

Never recall seeing passive x-overs that use a battery before??? Kind of hard to access in the sealed cabinet isn't it? What is the battery life?It's just to bias the one capacitor pair, with infinitesimal draw. Battery life is the shelf life of the battery, which, if you use the recommended lithium type, is 10+ years.

You can also mount the battery holder some place accessible, of course. I think it's also possible to buy battery compartments with little doors to build into stuff like this. :p

[GordonW]

Well, there you have it. Spend $150 on the WT2 and test your three drivers to see if they need remags.

Oldmics? Subwoof? GordonW? pelly3s? Edgewound? Care to add anything?

BTW, why is OCS charging $45 a pop to remag these days? Is it tied to the price of gasoline for their kick start generator or something? :rotfl:

$15 a pop at http://www.greatplainsaudio.com/

Actually, I do have a couple thoughts:

First, when testing the 2205s on the Woofer Tester, remember, that the ONLY relavant figure you'll need to match, is the Bl product (which can be derived once you have the basic T/S figures). Even if stuff like Fs, Qes, Qms and Vas are off from stock, it won't matter... suspension issues on the old cones isn't something to be concerned with, it's JUST the magnetic strength. If the Bl product is close (like within 10% of stock), then the frame is good-to-go for reconing.

Secondly, speaking of reconing... one option I might suggest, is like JBL has occasionally prescribed as a replacement woofer for the L200 and other similar series... you might want to recone the 2205 as a 2234... ie, use the 2235 kit, but leave out the mass ring. It'll wind up with a "compromise" response between the 2235 response and the 130A... you'll still get the "whomp" capacity of the 2235 (due to the longer voice coil winding), but you'll retain a bit more of the efficiency in the broadband (making driver level matching easier). The only expense, is a bit of loss in the lowest bass, due to the lower cone mass...

The nice thing, is that if you start out with it as a 2234, you can always have the dustcap cut off/removed, the mass ring installed, and a new dustcap installed... voila, instant conversion to a 2235. But, if you start with it as a 2235, it's very hard to go back, since once installed, those mass rings are hell to remove from a cone assembly, nondestructively...

As for re-magging sources... maybe it's just me, but IMHO, I'd trust Bill at Great Plains Audio to do the re-magging, before I would OCS. Sure, OCS should do a very good job, given their history... but Bill of GPA is a TRUE CRAFTSMAN. Can't go wrong, especially when he's willing to do the job at like, 1/3 the price!!

In fact, it'd be a real toss-up, whether I'd trust the JBL factory MORE than GPA, as far as remagging is concerned. It'd be just about a dead heat, AFAIK. Both should do the work just as it should be... no confidence issues with either, whatsoever!

Regards,
Gordon.

[Domino]

I'm about to get my (2) 136A reconed with the 2235A kits and is a new mass control ring included with each kit?

[4313B]

I'm about to get my (2) 136A reconed with the 2235A kits and is a new mass control ring included with each kit?
Yep.

BTW - Both drivers use the same mass ring.