Peter,
That's ok. I wouldn't want to ask you to translate it as that would be too big
of a job. I wish they had an English version, I'd buy it if I could find it for
the info.
Best,
Will
*********** REPLY SEPARATOR ***********
On 7/25/06 at 10:21 PM Peter Voelpel wrote:
>Will,
>
>It is also mentioned in my Siemens handbook of transmitting tubes together
>with the other safety measures on almost two pages.
>It is interesting to read that those measures were mandatory for claiming
>warranty replacement.
>I could scan that and put in on a website, but unfortunately it is in
>German
>only.
>
>73
>Peter
>
>-----Original Message-----
>From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
>Behalf Of Will Matney
>
>
>Exactly!!!!!
>
>That's the reason that if the grid is open, or floating, the tube turns
>into
>a diode and has no control of the electron flow. In effect, like you say,
>it
>would run away and eventually burn up. Way back when I first got into this,
>I said I never seen a problem with a grid fuse as long as the anode voltage
>was killed as soon as the fuse blew. One would never want to continue
>broadcasting after this condition happened. Since most amps monitor grid
>current, and plate voltage / current, it would be quickly seen on the
>meters
>if it happened. A trip could even be used to quash the B+ if this happened
>simply by watching the anode current. If it got too high, just kill the B+.
>
>I've not seen the Valvo article, but it would be a good read, and I'd
>personally like to see it.
>
>Thanks again,
>
>Will
>
>*********** REPLY SEPARATOR ***********
>
>On 7/25/06 at 9:24 PM Peter Voelpel wrote:
>
>>Hi Will,
>>
>>Yes, the grid must always keep its DC connection to ground not to turn
>into
>>a runaway condition by a positive charged grid, it does not matter whether
>>it is grounded grid or grounded cathode circuitry.
>>For that reason VALVO suggested the 50KOhm safety resistor from grid to
>>ground in their transmitting tube manual when the grid is not strapped to
>>ground.
>>
>>73
>>Peter
>>
>>-----Original Message-----
>>From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
>>Behalf Of Will Matney
>>Sent: Dienstag, 25. Juli 2006 20:52
>>To: amps@contesting.com
>>Subject: Re: [Amps] Fw: "Tubes 201" - How Vacuum Tubes Really Work
>>
>>Peter,
>>
>>Thanks! That is the very point I have been trying to get across all along!
>>Remember, the original threads were asking about a 3-500Z with the grid
>>resistor or fuse in G-G., or it was when I jumped in the mix There's been
>a
>>lot of other tubes and circuits dragged into the discussion, but I've
>tried
>>to center my comments around a 3-500Z G-G circuit. In grid driven circuits
>>though as in receivers and transmitters, or some amps, the grid can be
>made
>>to go positive for part of a cycle. This I think Rich means also. He can
>>correct me if I'm wrong.
>>
>>Thanks,
>>
>>Will
>>
>>
>>*********** REPLY SEPARATOR ***********
>>
>>On 7/25/06 at 8:40 PM Peter Voelpel wrote:
>>
>>>Hi Will,
>>>
>>>when the grid is kept grounded it can not become more positive then the
>>>cathode if that is grounded and not negative biased as well, except by RF
>>>drive on it above its choke.
>>>
>>>73
>>>Peter
>>>
>>>-----Original Message-----
>>>From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
>>>Behalf Of Will Matney
>>>
>>>Peter,
>>>
>>>On that, I agree it's the only way to make one positive (for only part of
>>a
>>>cycle). Are there any other ways to make the grid positive and the grid
>be
>>>at ground potential with the cathode at ground? A lot of amps cathodes
>are
>>>at ground potential unless biased.
>>>
>>>Best,
>>>
>>>Will
>>>
>>>
>>>
>>>*********** REPLY SEPARATOR ***********
>>>
>>>On 7/25/06 at 8:04 PM Peter Voelpel wrote:
>>>
>>>>Nothing is easier then that if the cathode is going/driven negative with
>>>>respect to ground.
>>>>Grid voltage is always measured from grid to cathode, not to ground.
>>>>
>>>>73
>>>>Peter
>>>>
>>>>
>>>>-----Original Message-----
>>>>From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
>On
>>>>Behalf Of Will Matney
>>>>
>>>>please explain how a grid becomes positive when tied to ground?
>>>>
>>>>
>>>>
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>>>
>>>
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>>
>>
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