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Altec Hollywood 604 Conundrum

lofiluther

lofiluther

New Member
Greetings good people,

A couple years ago, I inherited a pair of Altec 604 speakers in 9 cubic foot baltic birch cabinets from a retired electrical engineer in Silicon Valley. I'm a musician, songwriter and producer of independent label artists, so I was fascinated to dip my toe into the aural world of the famous 604 sound.

Except for a strange frequency response difference between the left and right speaker, I thought they sounded amazing. The midrange detail was unlike anything I've ever heard. I was told the speakers themselves were 604 B and from the late 1940s.

Then things got more interesting. When I opened the cabinets, I discovered one speaker was, in fact, a pristine Hollywood 604B with beautiful N1000-B crossover network.

The second speaker turns out to be an Altec Duplex 604 20 Ohm, with no letter demarkation and a serial number in the 3400s. It is beautiful, has an accompanying N1000-B crossover network.

So, now that I know what I have. . . what should I do?
 
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Here are some photos of the Altec 604 20 ohm speaker and N1000-B crossover after the cabinets were opened for the first time in 50 years:
 

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Beautiful!

Man, that is a conundrum! I'd want a matched pair of drivers, and after seeing that one I would have a tough time settling for anything less...

I've got nothing useful to contribute. :sigh:
 
The difference in sound you are hearing maybe from the difference in impedance from the 20 ohm speaker to the 16 ohm Crossover.They are pristine condition with original cones 20159.:yes:

Are they for sale by any chance ? If they are you should be able to get $2500 or more Minimum for those.Recently an original pair of pristine 604B's in 605A cabs sold for $14,000 on eBay.Take very good care of the cones in them, as they are irreplaceable Cone # 20159 GPA can't get those,or they just aren't made like that anymore (Paper Surround)

I personally would love to see more pictures of the other one,cabinets,etc.... Absolutely gorgeous ! You were given a treasure there.:yes:
 
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Yes! It is a conundrum. . . My initial reaction is to sell one speaker and replace it with one as identical as possible to whichever I keep so I end up with a pair of the same drivers.

An alternative would be to sell both of them and the N1000-B crossovers and keep the 9 cubic ft baltic birch cabs and get say, a pair of Great Plains Audio 604 8H III + crossovers to put inside.

Would there be a noticeable difference between the vintage 604 sound and the GPA versions?
 
I guess the other question embedded here is, if I go the vintage route, which speaker do I keep and try to build the pair around? the 604 20 ohm or the 604B? Is it likely I can find one or either?
 
I haven't had the opportunity to hear the GPA 604's but a couple times and briefly.Everyone over at the Altec board that has them Love them.However the early 604's with the larger sectoral horns and cones are supposed to be the cream of the crop.The 604 and the 604B you have are very close to each other WRT production dates they both have the yellow/gold labels.That should be around 1948-49.The 47's had white labels IIRC.

You may want to check out Todd's site. Altec User Board.You probably could get more help with those 604's there. :scratch2: Worth a try.They are a great piece of audio history and need to be treated as such especially in that condition (Mint)

http://www.hostboard.com/forums/f700/altec-users-board.html


BTW: You will have a hard time finding an exact match,if you do it will be expensive.IMO you have close enough match now, just a XO tweak you need maybe ?
 
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Is it possible to measure the impedance of the two drivers, independent of the crossover networks? You might have such a small mismatch that tweaking one of the networks might better align the pair.
 
Interesting dilemma you have here. If it were me, I'd sell both drivers with the crossover networks and start over with matched 604's. Otherwise it may be a loooooooooooong time till you are able to find another driver to match one of there two you have there...
 
You mentioned a difference in the frequency response. Why not switch the crossovers to see if the difference follows the crossovers?
If it does (and I suspect that it will) you can then sort out the crossovers. there is a good chance that the capicitors in the Xovers will measure differently.

The specs on the 604 and the 604B are pretty much identical other then the Xover Freq (the 604 crossed at 2KC ) and the low end Freq response (the 604 was speced down to 60Cy; the 604B down to 30Cy). I've always wondered if the 60Cy for the 604 was a misprint.

Where in the response do you hear a difference?

I have a pair of 604B's which sound identical. I never opened the Xovers because they sound fine to me.

I have a single 612 cabinet and the 604B's sound great in it although they sound better in a cabinet the size of yours.

Does anyone have a single 612 cabinet to spare?

Keep us posted on your progress.
 
DrRick said:
The specs on the 604 and the 604B are pretty much identical other then the Xover Freq (the 604 crossed at 2KC ) and the low end Freq response (the 604 was speced down to 60Cy; the 604B down to 30Cy). I've always wondered if the 60Cy for the 604 was a misprint.

I have a pair of 604B's which sound identical.I have a single 612 cabinet and the 604B's sound great in it although they sound better in a cabinet the size of yours.

Does anyone have a single 612 cabinet to spare?
Click to expand...

Hey Rick, Quite right Altec's old data sheets have quite a few misprints.I agree that those 604's should sound the same and am almost 100% positive it is the XO's that need rebuilding/replacement.Capacitors effective life span is 20-25 years give'er take a year or two.If those are still all original they are better than 60 years old.You get a pair of fresh XO's in there I bet problem solved and you will have a very rare pair of great sounding Altec's. :thmbsp:

Sorry about the 612 I only have a pair.
 
Interesting about the possibility of the 604 and 604B being nearly identical. Before I do anything else, I'll check out XO options. . . since I've never heard what either speaker sounds like except through 60 year-old crossovers.
 
lofiluther said:
Interesting about the possibility of the 604 and 604B being nearly identical. Before I do anything else, I'll check out XO options. . . since I've never heard what either speaker sounds like except through 60 year-old crossovers.
Click to expand...


I'd try them with an active crossover and see what happens.
 
Here's an additional conundrum for our OP: With the age and vintage of these drivers, I'd suggest more research be done to determine what he really has. Specifically, I'd check in with the Lansing Heritage crowd, Steve Schell, in particurlar, a resident historian there.

The low serial number is a little trigger for me that you may have some pretty original stuff. The conundrum is whether these are more valuable as collector items (on a shelf for display but not actually used) or whether they're to be used and dinked with to make them usable over the long term. If the latter approach is chosen, then the dust cover/felt will need to be inspected for integrity and the cones examined for cracks and other age-related problems before long term use. Ditto on the spider.

Again, get more references and details before a final decision is made. Our OP has a fine set of real-vintage (term seems overused these days) speakers on his hands. In these audio circles, that commands a bit of additional respect.

Cheers,

David
 
Heres another possibility. Since these speakers were produced before stereo, are we sure that both cabinets are identical? I have heard and experienced sound differences in cabinets that were identical ie one made of plywood and the other particle board..nails vers screws etc.

I also think with speakers this rare/old/collectible that I wouldn't put them in regular use. I have some old altec/trusonic speakers and they are only really used once in a blue moon. Because of the paper aging, cracks/tares can easily develop.

I am also hoping the OP realizes these speakers require very low input...using them with a solid state device is probably just asking for trouble...not even sure that I've seen SS with 16/20ohm output.

Cherish them, they are an amazing find. I had a pair of 604C's great speakers but the cabinets were incredibility small so I parted with them.
 
Good point; however, I know the maker of the cabinets built them at the same time, using the same template.

According to the story, my friend purchased the first speaker (what I now know to be the original Altec 604 20 ohm) from an executive at Ampex corporation (which used to have its headquarters in nearby Redwood City).

He then ordered a "matching" speaker directly from Altec (the 604B) and then built the cabinets. He kept the original wooden Altec shipping box the 604B arrived in, and gave it to me along with the speakers should I ever need to send it in to be serviced.
 
lofiluther said:
Good point; however, I know the maker of the cabinets built them at the same time, using the same template.

According to the story, my friend purchased the first speaker (what I now know to be the original Altec 604 20 ohm) from an executive at Ampex corporation (which used to have its headquarters in nearby Redwood City).

He then ordered a "matching" speaker directly from Altec (the 604B) and then built the cabinets. He kept the original wooden Altec shipping box the 604B arrived in, and gave it to me along with the speakers should I ever need to send it in to be serviced.
Click to expand...

Added vintage cache, there. Have any of the paperwork with the shipping carton? More vintage points for that sort of thing.

Nice to have the story with them, too.

Cheers,

David
 
More photos

So, It's taken me a while to get around to it, but I ventured into the back of the baltic-birch cabinet containing the Altec 604 B today and extracted it for a photo shoot. Also shot some photos of the vintage crossover unit and the original shipping box.
 

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