| "Oliver mod" for a CMV563. [message #423447] |
Tue, 12 May 2009 17:20  |
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 J.J. Blair
Messages: 12680
Registered: May 2004
Location: by the sea & sand |
Diamond Member |
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Oliver, based on your UM57 circuit mod, this is what I came up with for the CMV563. Would you mind taking a look and seeing if I missed something?
My UM57s are converted, but I'd like to do my CMV563, perhaps.
studio info
They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.
"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher
"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham
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| Re: "Oliver mod" for a CMV563. [message #423453 is a reply to message #423447 ] |
Tue, 12 May 2009 18:04  |
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Klaus Heyne
Messages: 2974
Registered: April 2004 |
Platinum Member |
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J.J., for those readers not 'in the know' please add a few pointers:
* why modding the electronics of that mic in the first place?
* what do you expect the specific changes to accomplish?
Thanks,
Klaus Heyne
German Masterworks
www.GermanMasterworks.com
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| Re: "Oliver mod" for a CMV563. [message #423463 is a reply to message #423453 ] |
Tue, 12 May 2009 19:23 |
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J.J. Blair
Messages: 12680
Registered: May 2004
Location: by the sea & sand |
Diamond Member |
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Sure thing, Klaus.
the real reason is that I was doing something to keep me from falling asleep on my plne flight, so I didn't wake up with a stiff neck!
But it's something I've wanted to do since Oli posted the mod on here for the UM57. My UM57s were rebuilt by BLUE, and Martins did a mod to them that is almost identical to the one that Oliver prescribes in his thread. I have noticed that my UM57s sound a great deal better than the stock ones I have heard. they are quieter, and have more clarity.
Oliver's mod adds a cathode biasing circuit, removes the hi pass filter cap before the grid, increases the resistance of the grid shunt, as well as increases the capacitance of the transformer coupling cap. What that all adds up to, hopefully, is a clearer sound. I'm not an electrical engineer, so I am relying on Oliver's math, with the assumption that these values, and the change in circuitry result in a better sound.
BTW, I just noticed that I'm not supplying voltage to the diaphragm, in my schematic. I tried adapting it from Oli's UM57 mod schematic, but the voltage for the diaphragm comes from pin 6, in his schemo, as well as the regular UM57 schemo. There is no voltage on pin 6 on the CMV563.
Should I have just taken the backplate straight to ground, and run the voltage between the diaphragm and the grind shunt resistor, moving that 10nF cap off the backplate?
If he or anybody could straighten out where I got that part of the path wrong, I'd appreciate it. I'm obviously not an electrical engineer.
Here's the original, btw:
studio info
They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.
"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher
"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham
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| Re: "Oliver mod" for a CMV563. [message #426017 is a reply to message #425997 ] |
Tue, 26 May 2009 19:54 |
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J.J. Blair
Messages: 12680
Registered: May 2004
Location: by the sea & sand |
Diamond Member |
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I have to see what I can get to fit in that position. That will determine what I use.
studio info
They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.
"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher
"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham
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