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Old 30th January 2003, 02:54 PM   #11
Joel is offline Joel  United States
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Quote:
Originally posted by SY
there's an output resistor to ground following the output cap- otherwise, the player would have horrible turn-on and turn-off bangs. And that resistor is acting as a remote grid leak.
Exactly. I think "Doc Bottlehead" (WTF???) is taking a big risk in hoping that all the units you hook this thing up to will have a resistance to ground.

Gabe, I can't believe you're dredging this up again?!!?
You keep confusing two issues - developing signal voltage, and providing a dc path between the grid and cathode. In your example, there is a path in there somewhere, or the tube will not function.
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Old 30th January 2003, 03:19 PM   #12
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GG was very common in amplifiers for radio:
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Old 30th January 2003, 03:21 PM   #13
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Grounded grid 3-400Z amplifier:
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File Type: jpg groundedgrid.jpg (35.2 KB, 356 views)
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Old 30th January 2003, 03:27 PM   #14
Joel is offline Joel  United States
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Jack, how is that relevant?
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Old 30th January 2003, 03:29 PM   #15
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Default RELEVANCY.

Hi,

Q:
Quote:
Jack, how is that relevant?
A: It is not.

Cheers,
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Old 30th January 2003, 04:12 PM   #16
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A rag-chewer eh?

Looks like an ARRL schematic, I'd guess a 60s or 70s Handbook, not 50s since the SS diodes...

Tim
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Old 30th January 2003, 04:14 PM   #17
Joel is offline Joel  United States
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Frank, is that really the flag of Belgium? I like it! Very understated.

I wish there was more blue color in the US flag.
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Old 30th January 2003, 04:18 PM   #18
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Default RAGS ALL OVER.

Hi,

Quote:
Looks like an ARRL schematic, I'd guess a 60s or 70s Handbook, not 50s since the SS diodes...
It's your typical grounded grid circuit and as such has no bearing on what Gabe put forward.

Joel,

Quote:
Frank, is that really the flag of Belgium? I like it! Very understated.
Actually it's the European Union jack.

The Belgian tricolours are like the German one (our first king was German) but the stripes are vertically aligned iso horizontally.

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Old 30th January 2003, 06:01 PM   #19
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Quote:
Gabe, I can't believe you're dredging this up again?!!?
You keep confusing two issues - developing signal voltage, and providing a dc path between the grid and cathode. In your example, there is a path in there somewhere, or the tube will not function.
BTW, WTF means "What The F$#%." Oh, BTW means "By The Way."

I only "dredged it up again" because I found a couple of examples to prove my point. Your contention was a path was necessary from the grid to cathode. If you said "internally", I would have agreed and that would have been the end of it. Theories and statements in electronics should require solid proof. So here I have presented this proof.

I am not confusing anything.

Do you know what you get when you put a positive voltage on the anode and a negative voltage on the cathode of a triode with nothing on the grid? A diode. The tube will conduct! The grid is there to control that initial flow of current. All that is really needed is a negative voltage with relation to the cathode in order to control the flow. That control can come from a pure AC source. I repeat myself here, that is not a practical practice, to be sure. But the tube will work. It will flow current. It will transfer the change in grid voltage. It needs a static grid to cathode voltage to bias it at idle. That can come from the cathode alone. There are some tubes whose specs allow them to work still in class A with a grid bias of zero.

I am sorry to sound condescending here, or patronizing, but it seems that with all your "book knowledge" you have missed something.

But, these two amp examples, of many I have come across, show that the tube will work without an external path.

If it is a problem for you to read things that are repeated, just ignore it. That is going to happen alot, since this is a subject with a finite number of subsets.

If you have a problem with me, just click on my profile and choose the "ignore" option below. Then anything I post you won't be informed of or be aware of.

But, you certainly don't dictate here or anywhere else in this country what whomever says. So... unless you like to have your freedoms revoked, get off my case! Because your freedom of speech stops with your trying to supress mine.

And if what I have posted here is wrong in any way, I would hope that the moderator would be the one to tell me so, not you.

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Old 30th January 2003, 06:15 PM   #20
Joel is offline Joel  United States
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Gabe, first you really need to calm down!
Second, this isn't some first amendment issue, and I certainly don't have a vendetta against you.

I expressed some.... frustration. I apologize. But I thought we had already covered this ad nauseum. However, I see there is still some confusion. Your "proof" is actually not proof of anything other than doc bottlehead's lack of a grid resistor!

As for your other points:
A triode is not a diode. I do not want, or ask it to behave like a diode. For a triode to "work" (ie. perform the functions of a triode) the grid needs a dc path back to the cathode. And no, this is not "internal" in any tube I've ever seen.

I'll happily repeat again, and I would welcome somebody trying to disprove it, but:
ALL THE ELECTRODES IN ANY TUBE MUST HAVE A DC PATH TO THE CATHODE.

Cheer up!

Joel
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