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View Full Version : I bought 9 old altec compression drivers and am trying to identify them-20 lbs each



MUSICCITY
11-19-2010, 11:51 AM
I just want to say thank you in advance for taking the time to read this and potentially steer me the right direction. I am a fan of vintage Altec, JBL, and Infinity and recently purchased a large number of vintage Altec pieces including several 1003B and 203B Horns. I also received 9 large 20 pound compression drivers in the deal. One of them is marked a 291-16a. However the original owner believed several of them to be 288's and probably C's. The problem is 8 of them have no stickers. All of the drivers appear virtually the same to me. I notice that a few of them have the bug/dust screen deep in the canal and several of them have the screen on the outer part of the canal at the gasket. Off hand that is the only difference I see among them.
Can anybody please tell me how to distinguish a 291-16a from a 288c or any of the other 288 drivers? I have looked up PDFs and have found two types of 291-16a drivers but no PDFs on the 288s. I greatly appreciate your time as I don't imagine I am the first to wonder how to determine the model number of a driver missing its sticker.
One neat note. I opened them up to check, and it turned out to be true. Each one of the drivers has an original 299 diaphragm with the Altec logo printed on the dome. He said that the place that used them originally chose to use those 16 ohm diaphragms. Thank you again so much!
One last note. I tried to upload some photos but they would not post. I kept getting a red exclamation point. I am new here so I will read up on what is wrong. In the meanwhile, I can email photos for reference if anyone wants.

speakerdave
11-19-2010, 12:21 PM
I just want to say thank you in advance for taking the time to read this and potentially steer me the right direction. I am a fan of vintage Altec, JBL, and Infinity and recently purchased a large number of vintage Altec pieces including several 1003B and 203B Horns. I also received 9 large 20 pound compression drivers in the deal. One of them is marked a 291-16a. However the original owner believed several of them to be 288's and probably C's. The problem is 8 of them have no stickers. All of the drivers appear virtually the same to me. I notice that a few of them have the bug/dust screen deep in the canal and several of them have the screen on the outer part of the canal at the gasket. Off hand that is the only difference I see among them.
Can anybody please tell me how to distinguish a 291-16a from a 288c or any of the other 288 drivers? I have looked up PDFs and have found two types of 291-16a drivers but no PDFs on the 288s. I greatly appreciate your time as I don't imagine I am the first to wonder how to determine the model number of a driver missing its sticker.
One neat note. I opened them up to check, and it turned out to be true. Each one of the drivers has an original 299 diaphragm with the Altec logo printed on the dome. He said that the place that used them originally chose to use those 16 ohm diaphragms. Thank you again so much!
One last note. I tried to upload some photos but they would not post. I kept getting a red exclamation point. I am new here so I will read up on what is wrong. In the meanwhile, I can email photos for reference if anyone wants.

291's look like 288 16G's; they have a flat back nearly the same diameter as the driver body and weigh 30 lb.'s

If the back of your drivers have a roundish bulb much smaller than the body of the driver they are earlier 288's. A 288c is an earlier 288.

If all of your drivers look like the one labeled 291 they may be a mixture of 291's and 288-G's which differ only in the type diaphragm that was originally installed.

Postable photos are in the correct file format and do not exceed the file size limitations.

MUSICCITY
11-19-2010, 03:33 PM
Thank you for taking the time to reply. These are not the flat ones. These are indeed ones that have the bulb end with Altec in raised lettering in the metal on the bulb. I had seen online that the 291-16a has the bulb too...I had read a person say they thought the 288c and the 291-16a were the same driver with different diaphragms. According to specs I have read...they are the same dimensions and weight exactly. They did have different diaphragms too. So I am not sure if that is a true statement. It appears it could be as other research shows they were marketed at the same time in the same year.
I believe these to be 288 drivers. There is numbering on the gaskets, but I don't believe that is indicative of the model. Just the 391 date stamp and four digit code. If you have any other thoughts or further insight please let me know.
Also, what is the largest size photo you can upload? I tried looking that up and couldn't find it. Thank you so much.

rgwalker
11-20-2010, 02:25 AM
I tried to upload some photos but they would not post. I kept getting a red exclamation point. I am new here so I will read up on what is wrong. In the meanwhile, I can email photos for reference if anyone wants.

Chances are is that your photos are too large. I don't know what the upper limit is here but it's not 36"+ and that's what they'll be if the camera is set for high res. Make smaller copies of the photos you want to use.

grumpy
11-20-2010, 12:17 PM
When you are editing a post, and click on Manage Attachments, you should
see a pop-up File Upload Manager window... there is a blue question mark
in the upper right corner... click on that (zip file category got chopped off,
but I'll leave that exercise to the reader ;)):

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