Hi Rick,
We didn't investigate the gold disks any further, we just were not interested that moment (off topic). Ofcourse, corono discharge is a major factor and the fact that similar things happen at lower voltages just mean that electrons are involved. Another problem may be the molecular layer of water which is present at the surface of metals under normal conditions. Therefore, some electrochemical reactions may also occur. I think this topic is pretty complicated and maybe other people know more about this than I do.
Now I predict that with lower corona discharge you will have less problems. So the question is, how fast is the deterioation with the best stators. Does it take more than 10 years?. If so, don't worry about it since it is a property of metals and you can't escape. Dust and dirt may even become the first problem.
Could you use a higher resistance? (non metal options)
Regards, MartinJan
We didn't investigate the gold disks any further, we just were not interested that moment (off topic). Ofcourse, corono discharge is a major factor and the fact that similar things happen at lower voltages just mean that electrons are involved. Another problem may be the molecular layer of water which is present at the surface of metals under normal conditions. Therefore, some electrochemical reactions may also occur. I think this topic is pretty complicated and maybe other people know more about this than I do.
Now I predict that with lower corona discharge you will have less problems. So the question is, how fast is the deterioation with the best stators. Does it take more than 10 years?. If so, don't worry about it since it is a property of metals and you can't escape. Dust and dirt may even become the first problem.
Could you use a higher resistance? (non metal options)
Regards, MartinJan
Since I started rebuilding transducer for Beveridge speaker owners about ten years ago, I have found that in the models 2, and 2SW, which were manufactured from 1974 to 1979, there was rarely any significant loss of the aluminum coating on the Mylar. Most looked as clean and nice as they did on the day they were made. They were sent to be rebuilt because they had lost enough diaphragm tension to cause trouble or simply because their owners wanted me to rebuild them so they could count on them for at least another 25 years. It is important to note here that the model 2 and 2Sw have their own built-in, direct-drive, otl amps.
The model 3, which was manufactured in 1979 and 1980, did employ a final step-up transformer. This change was made to make the speakers more saleable to people who already had their own amps. They were, and still are, very durable. So far, only three pair of model 3 speakers have needed to have their transducers rebuilt, but, when I did rebuild them, I found that much of the aluminum coating was gone. That is still not bad after 25 years, but it is not as good as on the 2 or 2SW. I should point out here that about 90% of the transducers which we manufactured in the 1970's are still playing very well and have not needed any repairs at all.
In the last few years, I have made transducers with both high resistance (megohms) and low resistance (kilohms) constant-charge diaphragms. Both worked very well with my electrodes. They actually performed significantly better with my electrodes than they did with conventional electrodes.
I am presently driving a pair of model 6's with transducers made with my electrodes and low resistance diaphragms. Because they are low resistance, they do not seem to suffer either from changing humidity, or from charge loss in the diaphragm after a heavy demand. They are being driven through step-up transformers and are not as clean as an otl system, but they do sound pretty good. We'll see how they hold up.
The model 3, which was manufactured in 1979 and 1980, did employ a final step-up transformer. This change was made to make the speakers more saleable to people who already had their own amps. They were, and still are, very durable. So far, only three pair of model 3 speakers have needed to have their transducers rebuilt, but, when I did rebuild them, I found that much of the aluminum coating was gone. That is still not bad after 25 years, but it is not as good as on the 2 or 2SW. I should point out here that about 90% of the transducers which we manufactured in the 1970's are still playing very well and have not needed any repairs at all.
In the last few years, I have made transducers with both high resistance (megohms) and low resistance (kilohms) constant-charge diaphragms. Both worked very well with my electrodes. They actually performed significantly better with my electrodes than they did with conventional electrodes.
I am presently driving a pair of model 6's with transducers made with my electrodes and low resistance diaphragms. Because they are low resistance, they do not seem to suffer either from changing humidity, or from charge loss in the diaphragm after a heavy demand. They are being driven through step-up transformers and are not as clean as an otl system, but they do sound pretty good. We'll see how they hold up.
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