Beovox Uniphase differences

Jon — Wed, 04 Nov 2009 23:20:12 GMT

Well, I’m sure some of you are aware of this information, but I wasn’t, so I’m posting it here for anyone else’s benefit.

When you read on Beocentral about some of the Beovox series of speakers, it states that the only difference between the original and “.2” versions are the addition of conventional binding posts for the speaker cable. It says this, for example, about the S80 speakers, and the MS150’s. This is wrong.

It never really clicked to me before, but I’ve noticed that the original Beovox series (of the “revised Uniphase” range) used a clear, polymer diaphragm material in the midrange filler drivers, whereas the “.2” models seemed to switch to a coated fabric type of membrane. I haven’t opened up the polymer ones, but the fabric domes have a thin ring of copper glued on the inside of the motor, presumably to stabilize the magnetic flux field. Doesn’t look like it would work very well, but hey…. They are both SEAS drivers, and look almost identical to the “new” Scan Speak budget range dome mids they just came out with (I guess Vifa didn’t want those to go to China too).

Here’s the mids from my MS150’s and my S80.2’s I’m trying to restore.

I notice also that my MS150’s use SEAS tweeters, and the S80.2’s use Vifa tweeters. This might just be because of the difference between the quality of the speakers, but I don’t think so. My reasoning behind that is because I bought a crossover for an S80 speaker to put into one of my S80.2’s, thinking they would be the same. However, the filter design is completely different. It looks like the electrical slopes and Fc points are different. So, it makes me reason that the “.2” series speakers switched to Vifa tweeters as well. The Fc’s for the S80.2 Xover are 800 and 4,000Hz, respectively. For the MS150’s, they are 900 and 3,000Hz.

Anyway, for anyone thinking that binding posts are the only difference between original and “.2” series speakers, this is wrong, and you need to be careful that what you try to piece together will actually work. There are quite a few differences in fact.

FYI

Jon

The Workbench

Beovox Uniphase differences