Posted on Saturday, April 14, 2007 8:44 PM
Another thing I'm kind of in the closet about; I'm kind of a vintage-geek where electronics are involved. While I'm really fond of my Pioneer DVD-player and harman/kardon 5/7.1 surround receiver with DTS and the whole shebang, I can be over the moon about a reel-to-reel tape recorder at the same time (I have two Akai decks myself) and I enjoy a movie off of Laserdisc as well as I do from DVD.
I own a pair of Philips Motional Feedback (MFB) loudspeakers, which I use as front speakers in my 5.1 setup. These speakers were introduced in 1974, were hand-built and therefore quite expensive.
However, they are quite durable as well. About 10 years ago, I got my paws on a pair of 587's, built in 1979; one of the top models of the line (an extensive overview can be found at this Dutch
web site). Three-way, actively filtered and amplified, and the tight bass resulting from the interaction with the feedback system.
A while ago, I found the high range seriously lacking, and when I did some tests, it sometimes disappeared completely, while returning a moment later, only to disappear again in the next.
Now, I know a thing or two about electronics, and the guys over at mfbfreaks.nl were kind enough to send me a service manual, so I removed the back plate and gave the input circuit a once-over.
As I said earlier; these things are over 20 years old, and thus some components are starting to wear down, especially electrolytic capacitors; they tend to dry out and thus lose their capacity.
One of the brilliant things about these speakers is that they were built without any integrated circuits. Everything is discrete, and as a result, easily replaceable (well, save for the transformer and the drivers).
So, after getting some new capacitors and soldering them into the filter-pcb, the speaker once again sounds like it should. :)
Unfortunately, the guys at the electronics shop gave me three wrong capacitors, so the other speaker has to wait for his revision until after the week-end.
Cheers, K.