BOSE 901's -What series????

[jimfed1]

I just purchased a pair of Bose 901's at a pawn shop, and am curious what series they are. It makes no mention on the label. I have serial numbers if that helps. There must be some simple way to figure out the "era" of these things. Any help would be appreciated.

[ShinOBIWAN]

Weren't the 901's the flagship of the bose range back in the 80's?

[dhenryp]

I built Bose 901 clones ~1974 so I think the real 901s probably came out at least a couple years earlier. The first thing to look for is if the box is sealed or vented. The original 901s were sealed while later versions in the 90's had two vents sticking out of the back panels.

[69stingray]

Try searching EBAY for Bose 901 and compare different pictures to match up the ones you have. Just a suggestion.

[RCBandwidth]

You should be able to tell by the equalizer that came with them.You must have the special eq or they are useless...

[Cal Weldon]

How are the surrounds?

[dhenryp]

Originally posted by RCBandwidth
You should be able to tell by the equalizer that came with them.You must have the special eq or they are useless...

Most, if not all, came with an equalizer so an equalizer by itself does not tell you much. In the earliest versions the equalizer gave you a boost of ~18db at the low end (20-30hz?) and about 12db at the high end. These were very inefficient speakers that needed lots of power to go down low. The later versions used a vented design to give you better efficiency so I imagine the low boost was probably cut back quite a bit.

You actually can emulate the Bose equalizer reasonably well with a graphic equalizer or even receiver tone controls. In fact, I'm running my clone 901s in the basement right now with the tone controls turned up on my equally old Pioneer receiver (Pioneer SX1010). My equalizer clone died years ago but before I did I compared it to the tone control setting and it was very hard to tell the difference.

Cal is right about the surrounds. The originals had foam surrounds and they often rot (though mine are 30 years old, the last 20 in my basement, and the surrounds are fine).

BTW: Bose still sells 901s and they are still their "top of the line".

[dshoaf]

but I suspect you may have the Series I or II. These will have walnut laminated tops and bottoms and will have cloth grilles that wrap around all 5 sides. There should be only 2 thumb-nuts on the bottom for speaker wires. The should be no ports or plastic on the cabinets anywhere.

All other 901 models will have 3 ports on the V-shaped backside with 2 of them looking like the back end of a jet engine. Many of this series of III/IV/V will have 3 terminals for speaker wires.

Yes, the equalizers were built specifically for each series but you can indeed approimate one with parametric equalizers with about 18db of treble/bass boost capabilities.

A picture would help to get it closer.

Cheers,

David

[RCBandwidth]

For Dhenryp: The Eq has the series number on it(on the rear).

[dhenryp]

Originally posted by RCBandwidth
For Dhenryp: The Eq has the series number on it(on the rear).

Ah! That's one thing I did not copy on my clone