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RE: Sorry I missed your earlier post.

Main issue with Bev speakers is oscillation of the direct-drive amplifiers. They seem to be very prone to do that. You can have them dialed in with used tubes. Then if you replace the tubes with new ones, that naturally will have a higher transconductance, there are more problems with oscillation. Between Bill Thalmann and me, we recently came to the realization that the 1K grid-stop resistors used on the power tubes are actually not "correctly" installed for optimal prevention of oscillation; the leads are too long on the side of the resistor nearest to the grid. I am next going to replace the 1K grid-stops with 2.2K Rikens that I have here, and I will take that opportunity to mount them right "on" the grid pins of the tube socket, close as possible. I have hopes that this will help for the one amplifier (with new tubes) that is thrown into oscillation when fed from an SACD source. (I also learned from Bill that SACD players put out quite a lot of very very high frequency spurious noise.) The other amplifier, still with its old original tubes, has no issues with SACD.

Beyond that stuff, other Bev owners tell me that they have had issues with blown power transformers (probably due to old leaky electrolytics or blown rectifiers) and with getting the ESL panels rebuilt. I bought some extra alu-coated mylar from RM Labs, just in case that is ever needed. It's cheap insurance.

On the other hand, considering the age of any Beveridge speaker, they are remarkably long-lived. One could only wish that the Sound Lab speakers would be as durable, actually.


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  • RE: Sorry I missed your earlier post. - Lew 10:50:55 02/26/14 (0)

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