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#2878827 - 09/13/17 07:31 AM Hammond A100 speakers
GRollins Offline
Senior Member

Registered: 09/01/17
Posts: 353
I tried the search engine, but either I wasn't asking the question properly or this hasn't come up in a while, maybe ever. Besides, there's the Google effect, where you ask a question and get six billion hits, none of which are relevant. Yes, Hammond, A100, and speaker will get you responses, but they're all about Leslies and carrying equipment around and so forth.

I recently acquired a Hammond A100 in remarkably good condition. The one thing that needs attending to is that one or more of the speakers are blown. I haven't yet pulled them to check (been rebuilding the master bathroom--a thankless task), but I believe it's the main speaker(s), not reverb, which appears to be a totally different driver. They're okay up to medium volume as long as I stay off the pedals. Once I get loud or hit a pedal, it gets raucous.

So...today's question is:
1) What's the go-to driver for replacing a blown A100 internal speaker? I believe I read somewhere that the originals were Jensens of some description, but I don't even know if that's the case.
2) Would it be better to go with an external speaker cabinet of some description? Any answer that contains the word "Leslie" will likely have to go on the back burner for the time being. It's been an expensive year. I bought the A100 and a Korg Kronos X in a single week and that's not the only money I've spent, so unless you know where a Leslie is available really, really cheap, it'll have to wait. For the record, I'd like to note that I am "officially" a bass player, so I have an assortment of bass cabinets available. No, I haven't tried them yet...see master bathroom comment above. (Guys/gals, it is flat-out killing me to have this fun new stuff in the house and not have time to mess with it!)
3) Is reconing a realistic option? As far as I can tell, the drivers are the original ones from 55 years ago. Direct replacement cones are unlikely to be available, though I may be wrong. If I'm faced with putting in a generic cone, then I might as well set these baskets aside and go with option #1. The only point I can see to reconing is to return the driver to stock condition. If it's not stock, then it's not going to have the original tone and I might as well try something else.
4 [sorta 2a, I guess]) While Hammond may have intended their speakers to be full range in some sense, they weren't capable of what today's speakers can do. Would something like a PA speaker (EV, QSC, etc.) be a good choice or would you loose "magic" by going modern on the speakers? In an entirely different experiment, I tried the Kronos through Celestion G12Ms and didn't like it at all. Jon Lord, I ain't. Back to full range speakers there.

Grey
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#2878843 - 09/13/17 08:44 AM Re: Hammond A100 speakers [Re: GRollins]
mate stubb Offline
Grand Poobah of the Trebuchet
10k Club

Registered: 10/26/03
Posts: 15500
If you have a speaker with a torn cone and the voice coil is still OK, it's completely possible to repair with tissue paper and contact cement.

Use contact cement because it dries rubbery and not stiff. Cut rectangles of kleenex or toilet paper large enough to cover both sides of the tear, then paint contact cement on, repeating until the entire tear is covered.

I rescued many a speaker in my completely broke days.
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#2878847 - 09/13/17 08:55 AM Re: Hammond A100 speakers [Re: mate stubb]
WesG Online   shocked
MP Hall of Fame Member

Registered: 02/16/13
Posts: 3060
Loc: Inverary, ON, Canada
Where do you live?

I know where there is a $300 CAD Leslie 251.

Save your pennies on speaker replacement and get a Leslie. Repairing the stock speakers is the best choice. They are specifically voiced for the organ and replacements might not sound as good (or they might sound awesome, depending on your taste, I suppose).

Wes
_________________________
Hammond: Split L111, '58 M3, '59 B3, Northern DV
Leslie: 760, 51C, 147, 145
Yamaha: CP4, DGX-620, DX7II-FD-E!, PF85
Roland: VR-09
Band Site: http://DrBombay.ca/

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#2878850 - 09/13/17 09:00 AM Re: Hammond A100 speakers [Re: mate stubb]
GRollins Offline
Senior Member

Registered: 09/01/17
Posts: 353
Moe,
I've used rubber cement in the past, rather than contact cement, but the philosophy is the same. As far as I can tell the cones are intact, looking from the back. The fabric is in near perfect condition in the front, so no one's hit them from that direction.

If there were screws or plugs, I'd already have taken the drivers out for inspection. Unfortunately, the wires are soldered, which is fine from Hammond's point of view, but it's inconvenient for me. I've got soldering irons and test gear out the wazoo, but haven't taken the time yet to take a soldering station into the room where the Hammond is. I'll get there.

Grey


Edited by GRollins (09/13/17 09:01 AM)
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#2878853 - 09/13/17 09:02 AM Re: Hammond A100 speakers [Re: GRollins]
GRollins Offline
Senior Member

Registered: 09/01/17
Posts: 353
Wes,
I'm in central South Carolina. Canada's a loooong ways away.

Grey
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#2878861 - 09/13/17 09:38 AM Re: Hammond A100 speakers [Re: GRollins]
WesG Online   shocked
MP Hall of Fame Member

Registered: 02/16/13
Posts: 3060
Loc: Inverary, ON, Canada
Okay. I'll keep my eyes peeled for you!

And based on your observation of no physical defects..........it's probably an amp problem.

You're going to find two speakers wired in parallel connected to a power amp connected to the AO-28, and a single reverb speaker connected to a totally different amplification system (but which uses the power amp speaker signal as its input).

Wes
_________________________
Hammond: Split L111, '58 M3, '59 B3, Northern DV
Leslie: 760, 51C, 147, 145
Yamaha: CP4, DGX-620, DX7II-FD-E!, PF85
Roland: VR-09
Band Site: http://DrBombay.ca/

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#2878880 - 09/13/17 10:18 AM Re: Hammond A100 speakers [Re: WesG]
Sven Golly Offline
KC Ambassador of Goodwill
10k Club

Registered: 11/12/03
Posts: 12183
Loc: Toronto, ON
Originally Posted By: WesG
Where do you live?

I know where there is a $300 CAD Leslie 251.

Save your pennies on speaker replacement and get a Leslie. Repairing the stock speakers is the best choice. They are specifically voiced for the organ and replacements might not sound as good (or they might sound awesome, depending on your taste, I suppose).

Wes


Hey Wes, check your PM's please (in about 3 minutes). wink
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#2878897 - 09/13/17 11:16 AM Re: Hammond A100 speakers [Re: Sven Golly]
GRollins Offline
Senior Member

Registered: 09/01/17
Posts: 353
Bringing people together...my specialty. Sounds like that Leslie might have found a new home.

Okay, I've decided that the master bathroom can take a powder, so to speak(er). I'm on the A100 now.

And what to my wondering eyes should appear...

What's this?

The spider on one of the drivers has come completely unglued. It's just flapping around. I've been doing audio and electronics since the '70s and I've never seen a clean detachment like this.

Hmmm...

Okay, that explains the sound I was hearing. The cone was locked by friction up to a certain wattage, at which point the motive force overcame the friction and I started hearing the voice coil rub.

Can the driver be saved? Good question. I suppose theoretically I could glue the spider back down, but I foresee problems:
1) Alignment of the voice coil while I attempt to re-glue the spider. Not unmanageable.
2) How clean is that joint, mechanically? I can clean the basket with a Q-tip and do a pretty good job, but the spider itself...I dunno...anything I use to try to clean it might harm the fabric. This one's a potential booger.
3) Has anything gotten into the magnetic gap over the years? If so, there's not going to be a good way to clean it out. This one's a potential hairy booger.
4) But all of the above is for naught if the coil or coil former has been damaged by rubbing the center post. From the sound of it, the coil former is rubbing, not the coil itself. It sounds like a clean rub, if that makes sense, i.e. not gritty. This one's a potential deal killer, but I'm hopeful.

Questions:
1) What do people use to glue spiders these days? It's been ages since I've messed with this sort of thing and all my older stuff has dried up. There might be something new and cool out there.
2) Can I run the thing with external speakers? Given that the A100 derives a signal for the reverb from the speakers themselves, it's not a simple matter of patching in, say, one of my bass cabinets. The circuitry might not like having that input floating around in mid air.
3) Where do I go for reliable schematics for a late 1962 A100? Looks like I'm going to have to bone up on theory and operation of Hammonds. (Like I don't have anything else to do these days...)

Grey


Edited by GRollins (09/13/17 11:18 AM)
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#2878901 - 09/13/17 11:19 AM Re: Hammond A100 speakers [Re: GRollins]
Sven Golly Offline
KC Ambassador of Goodwill
10k Club

Registered: 11/12/03
Posts: 12183
Loc: Toronto, ON
Here you go:

Hammond-Leslie FAQ

There's a link to the A-100 Service Manual on that page, or just click here. twothumbs
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"...there's something you better understand about me, 'cause it's important and one day your life may depend on it. I am definitely a madman with a box."

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#2878920 - 09/13/17 12:39 PM Re: Hammond A100 speakers [Re: Sven Golly]
Markyboard Offline
MP Hall of Fame Member

Registered: 02/10/01
Posts: 5095
Loc: Springfield, Virginia
New territory for me but you got me interested and I found this. The videos are excellent. They're not specific to Leslie speakers but I think the process is pretty much the same.
Updates with lots of pictures would benefit a few of us here.
Good luck!

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#2878921 - 09/13/17 12:59 PM Re: Hammond A100 speakers [Re: Sven Golly]
GRollins Offline
Senior Member

Registered: 09/01/17
Posts: 353
Sven Golly,
Thanks for the link.

The driver's out of the cabinet and desoldered. I'm not so sure that the coil will survive after all.

The basket has P12N stamped on it, which sounds like a Jensen part number, so I looked. Yes, Jensen has a P12N available at this time and the no-bell version even looks similar to this one, albeit mine has a black basket instead of the current dark grayish-green.

Antique Electronics sells the P12N no bell for ~$215. I haven't looked at Musician's Friend, et. al. but I'm assuming they'll be similar in price.

Or I can have it reconed for ~$75 plus shipping.

Or I can buy a recone kit for ~$35.

I'm going to mull this over, but will probably end up buying a recone kit and doing it here. The problem there being finding the time. Decisions, decisions...

I knew the thing had at least one bad driver when I bought it, but A100s don't come up every day, especially at the price I got it for, so if I put in a bit for the driver, I'll still be a happy camper. As a temporary measure, I'll tag a 4 Ohm cabinet into the wiring harness with the reverb wiring intact. I've got guitar cabinets with Celestions and bass cabinets with Eminence drivers, plus a few odds and ends. I think I can make this work while the original drivers are out. (The other driver's good, but I might as well do this cleanly; keep the impedance closer to the design target so as not to freak out the reverb circuit.)

Grey
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I'm not interested in someone's ability to program. I'm interested in their ability to compose and play.

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#2878956 - 09/13/17 04:31 PM Re: Hammond A100 speakers [Re: GRollins]
GRollins Offline
Senior Member

Registered: 09/01/17
Posts: 353
Interim report: Hammond A100s sound pretty good through Celestion G12H (55Hz) drivers. Not as much bass from the pedals, but it's tighter; a trade off. I think I might like the mids and highs better. Maybe.

Grey
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I'm not interested in someone's ability to program. I'm interested in their ability to compose and play.

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#2879017 - 09/13/17 09:10 PM Re: Hammond A100 speakers [Re: GRollins]
B3Nut Offline
Platinum Member

Registered: 04/09/01
Posts: 1193
Loc: Mount Horeb, WI USA
Keep an eye on eBay. 12's from A-100's show up all the time. Less valuable to guitar players are the Heppner drivers (EIA code 575) that mid-'62 and later A-100 series instruments used. Arguably the best-sounding of the lot TBH. The Heppner mains have a fairly beefy square-ish horseshoe Alnico magnet assembly. The Rola and Jensen driver used in A-100's for mains had large round Alnico magnets.


TP
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