23-12-2016, 04:22 PM
Can I ask a question to clear a point up?
More than once you've said there is no schematic. But then you post a link to one.
So, the schematic in post #10 is the original Altec model. But what you don't have is a schematic that shows EMI's modifications to the Altec unit?
It seems to me that if you reduce C4, you'll shorten the release time by a similar proportion. So when you say that 0.22uF made things go wrong, it is possible that the owner forgot to adjust the release time control? Perhaps P2 and R9 need increasing?
At short attack times, you run the risk of the audio being modulated into distortion - that's just what happens. Adding another time constant (making a second-order filter) might help matters. Or, adding a "hold" facility - whereby the control voltage stays constant for a brief time before sinking according to the release time constant - is another trick (also used in PPM meters).
In short, what you're trying to achieve is quite complex, and it's no wonder if the people who have figured it out wish to keep it to themselves.
More than once you've said there is no schematic. But then you post a link to one.
So, the schematic in post #10 is the original Altec model. But what you don't have is a schematic that shows EMI's modifications to the Altec unit?
It seems to me that if you reduce C4, you'll shorten the release time by a similar proportion. So when you say that 0.22uF made things go wrong, it is possible that the owner forgot to adjust the release time control? Perhaps P2 and R9 need increasing?
At short attack times, you run the risk of the audio being modulated into distortion - that's just what happens. Adding another time constant (making a second-order filter) might help matters. Or, adding a "hold" facility - whereby the control voltage stays constant for a brief time before sinking according to the release time constant - is another trick (also used in PPM meters).
In short, what you're trying to achieve is quite complex, and it's no wonder if the people who have figured it out wish to keep it to themselves.
