Thanks Chris !
And just to ad ,
tube in this design usually last for decades , in my studio most of the time Ecc83 tube work in keyed off state , with cathode bypassed to ground line via small mute switch , only when I need to speak something in ether and to communicate with other AM pirates I switch this pre. in on position ,
some builders of this simple mic pre. noticed to big developed AF output voltage gain .
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Figure 10 indicates that the capsule is modified for 3-wire. However, I wonder about figure 11. It looks to me that J1 must not be in the capsule, because even if it was 3-wire ( EM173 ), there is still no connection point to the gate of the internal JFET. So, the capsule must be either 2-wire ( EM172 ) or without internal circuitry (like the EM23 ).
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Trying to sort this out before purchasing components.
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Yes, that is correct the first circuit was actually published years earlier at the mic builders Yahoo site, sort of the ultimate Linkwitz mic. I'm sure you could get this to go until the diaphragm collapses. I think I built the second with one of the TSB FET-less capsules. They are quite good and much cheaper than the Primo capsules. Though for ultimate performance the EM21/23 at $60? would edge them out (I think). The capacitive feedback version that we used at SY's is probably your best trade off, it has 110mV/Pa sensitivity and still more than enough DNR for anything less than a drum kit at a couple of feet. I built a little 300Hz pressure chamber and the first one did 150dB SPL.
John PM me before you buy anything, I'm doing a pre-retirement clean out.
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Unavoidable diaphragm resonance damped by careful design of the backplate. There is a huge amount of literature on the details and all the issues around this. Some use careful equalization to "cheat" a little on the noise specs by working around the A weighting.
Since WWII started in 1939, you're both wrong!
For Americans, it didn't really start until December 7th, 1941. And I would argue that that was when it truly became a "world war." I mean, how can you really call it a "world war" when you're leaving out an entire hemisphere?
se
I mean, how can you really call it a "world war" when you're leaving out an entire hemisphere?
se
doesn't stop MLB . . .
Cheers !
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May-I politely suggest USA is not the center of the world ?
The war began in 1939. (In fact, earlier with the Spanish war). In Europa. And progressively extended to the rest of the world, including US after Pearl Harbour.
It was the same war, called later the "Second world war".
I would add that US had not to suffer the war in his own territory. So, for all the civilian populations of all the countries involved, massacred, martyred, bombed, deported, since 1939 (and before in Spain), I feel in your remark a little lack of consideration and respect for their millions of dead (between 50 and 70).
What does not detract from the huge losses that US soldiers have suffered (416 800 ?), both in Asia and Europa, the sacrifices of this country, and to the major contribution that the United States has offered to the world to liberate us form the Nazi yoke.
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For Americans, it didn't really start until December 7th, 1941. And I would argue that that was when it truly became a "world war." I mean, how can you really call it a "world war" when you're leaving out an entire hemisphere?
se
Which hemisphere are Australia and New Zealand in?
For Americans, it didn't really start until December 7th, 1941. And I would argue that that was when it truly became a "world war." I mean, how can you really call it a "world war" when you're leaving out an entire hemisphere?
se
Smiley noted, but Canada was at war with Germany in 1939.
PS:. Sorry I brought it up.
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Hi Scott,
If a tube was used that had a very low gm (a different tube type), would it be possible to have too much voltage appear across the mic assembly?
-Chris
Thanks. Yes I knew it was a cascode, but I didn't know if it were possible for the FET to have a relatively high voltage developed across it. Just curious since I hadn't seen this circuit before.
If a tube was used that had a very low gm (a different tube type), would it be possible to have too much voltage appear across the mic assembly?
-Chris
You sure can. And then you can point to the part of my post where I said that it was. When you find yourself unable to find it, you can turn your attention to the smiley face at the end of my post, which I had hoped would indicate that my "argument" was not an entirely serious one. But I apparently hoped for too much.
Once you've done that, pour yourself your favorite adult beverage, find yourself a nice comfy chair, and chill out.
se
You are correct, sir. And thank you for noting the smiley, which is more than I can say for someone else.
And don't be sorry for bringing it up. It was a great smartass reply.
se
Eastern hemisphere last time I studied any geography. But that was a long time ago so they may have changed the prime meridian since then.
se
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