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FS: Knight KG600B Tube Tester
Knight KG-600B Tube Tester
Excellent shape - just missing top cover. Internal chart included. Good working condition. Will sell for $50.00 plus shipping See web page for details. Do not reply direct to this ad - using a spam blocked address. Reply ONLY to the e-mail address on web page. For picture and details see: http://home.cfl.rr.com/happysurfer/miscpart.htm and http://home.cfl.rr.com/happysurfer/radios.htm |
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John Goller, k9uwa wrote:
In article , says... Knight KG-600B Tube Tester Excellent shape - just missing top cover. Internal chart included. Good working condition. Will sell for $50.00 plus shipping OK U guys without any test equipment ... here is a toob tester for 50 bucks.... Brian didn't put any pictures of it on his web site... so ask if it covers the 4,5,6,7,8 pin old style tubes ... I am betting it does.. I believe it does, but what you need to ask is whether it is a real transconductance tester or just a mutual conductance tester. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
John Goller, k9uwa wrote:
In article , says... Knight KG-600B Tube Tester Excellent shape - just missing top cover. Internal chart included. Good working condition. Will sell for $50.00 plus shipping OK U guys without any test equipment ... here is a toob tester for 50 bucks.... Brian didn't put any pictures of it on his web site... so ask if it covers the 4,5,6,7,8 pin old style tubes ... I am betting it does.. I believe it does, but what you need to ask is whether it is a real transconductance tester or just a mutual conductance tester. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
....I'm sure you meant "real transconductance tester or just an
emission tester" in the sentence below....I believe that "Transconductance" and "Mutual Conductance" are synonomous WRT tube testers! IIRC, the Knight 600B is an emission type tester. 73, Leo On 6 Oct 2003 15:49:05 -0400, (Scott Dorsey) wrote: snip I believe it does, but what you need to ask is whether it is a real transconductance tester or just a mutual conductance tester. --scott |
....I'm sure you meant "real transconductance tester or just an
emission tester" in the sentence below....I believe that "Transconductance" and "Mutual Conductance" are synonomous WRT tube testers! IIRC, the Knight 600B is an emission type tester. 73, Leo On 6 Oct 2003 15:49:05 -0400, (Scott Dorsey) wrote: snip I believe it does, but what you need to ask is whether it is a real transconductance tester or just a mutual conductance tester. --scott |
Scott Dorsey wrote:
I believe it does, but what you need to ask is whether it is a real transconductance tester or just a mutual conductance tester. It's 50 bucks- likely it's an emission tester. These are much more useful than, say, a TV7 because you can own it now and not have to save money for years. If a person would like to use a Hickok but never buys one and has to guess as to tubes, how are they ahead of the game? I'm absolutely certain many of you would say it's MUCH better that they NEVER buy a tester their entire lives if they can't afford a high end Hickok. Yeah, everything else is a toy, uh huh- and the TV7 doesn't even give a direct reading IIRC but requires math each time ! That's a bit like my hippie friends here who walk to work because their 1959 VW Transporter is perpetually in the shop or a ditch (they can't bear to be seen driving a less than cool car). John H. |
Scott Dorsey wrote:
I believe it does, but what you need to ask is whether it is a real transconductance tester or just a mutual conductance tester. It's 50 bucks- likely it's an emission tester. These are much more useful than, say, a TV7 because you can own it now and not have to save money for years. If a person would like to use a Hickok but never buys one and has to guess as to tubes, how are they ahead of the game? I'm absolutely certain many of you would say it's MUCH better that they NEVER buy a tester their entire lives if they can't afford a high end Hickok. Yeah, everything else is a toy, uh huh- and the TV7 doesn't even give a direct reading IIRC but requires math each time ! That's a bit like my hippie friends here who walk to work because their 1959 VW Transporter is perpetually in the shop or a ditch (they can't bear to be seen driving a less than cool car). John H. |
In article , Hagstar wrote:
It's 50 bucks- likely it's an emission tester. These are much more useful than, say, a TV7 because you can own it now and not have to save money for years. If a person would like to use a Hickok but never buys one and has to guess as to tubes, how are they ahead of the game? I'm absolutely certain many of you would say it's MUCH better that they NEVER buy a tester their entire lives if they can't afford a high end Hickok. Yeah, everything else is a toy, uh huh- and the TV7 doesn't even give a direct reading IIRC but requires math each time ! Actually, some of the cheap Hickok units are real transconductance testers, and some of them do show up for next to nothing now and then. They aren't any TV7, but they sure beat out the drugstore testers. Some of the emission testers are no better than drugstore testers, and they have a tendency to indicate perfectly good tubes are bad, or vice-versa. This can be extremely frustrating if you ask me. They'll find open filaments and poor emission, but other problems (especially on beam power tubes) do not show up on them. When you're paying some of the bloody insane prices on power tubes thes days, a good tube tester can pay for itself in short order in the tubes you don't throw out even though they are fine, and in the tubes you don't have to keep around for substition testing. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
In article , Hagstar wrote:
It's 50 bucks- likely it's an emission tester. These are much more useful than, say, a TV7 because you can own it now and not have to save money for years. If a person would like to use a Hickok but never buys one and has to guess as to tubes, how are they ahead of the game? I'm absolutely certain many of you would say it's MUCH better that they NEVER buy a tester their entire lives if they can't afford a high end Hickok. Yeah, everything else is a toy, uh huh- and the TV7 doesn't even give a direct reading IIRC but requires math each time ! Actually, some of the cheap Hickok units are real transconductance testers, and some of them do show up for next to nothing now and then. They aren't any TV7, but they sure beat out the drugstore testers. Some of the emission testers are no better than drugstore testers, and they have a tendency to indicate perfectly good tubes are bad, or vice-versa. This can be extremely frustrating if you ask me. They'll find open filaments and poor emission, but other problems (especially on beam power tubes) do not show up on them. When you're paying some of the bloody insane prices on power tubes thes days, a good tube tester can pay for itself in short order in the tubes you don't throw out even though they are fine, and in the tubes you don't have to keep around for substition testing. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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Mike Knudsen wrote:
Can someone explain how a tube can show good cathode emission, but not be up to snuff in transconductance? A tube's performance depends on teh geometry and structure of its grids and plate and their spacing. If hte tube hasn't been physically knocked around, the geometry hasn't changed. So if the cathode is putting out the electroncs, how can the tube not be up to snuff? Let's say you have a beam power tube that was used on an amplifier with a screen grid supply problem, and the screen grid drew current and burned completely away. There's nothing left any more. That tube will test just fine on an emission tester. The cathode is putting out plenty of electrons, but the tube Gm and mu are way off because the geometry itself has been radically altered. It tests fine, but it will not even come close to working in a circuit. Okay, it's an extreme example, but plenty of things go wrong with tubes other than the cathode getting stripped. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
Mike Knudsen wrote:
Can someone explain how a tube can show good cathode emission, but not be up to snuff in transconductance? A tube's performance depends on teh geometry and structure of its grids and plate and their spacing. If hte tube hasn't been physically knocked around, the geometry hasn't changed. So if the cathode is putting out the electroncs, how can the tube not be up to snuff? Let's say you have a beam power tube that was used on an amplifier with a screen grid supply problem, and the screen grid drew current and burned completely away. There's nothing left any more. That tube will test just fine on an emission tester. The cathode is putting out plenty of electrons, but the tube Gm and mu are way off because the geometry itself has been radically altered. It tests fine, but it will not even come close to working in a circuit. Okay, it's an extreme example, but plenty of things go wrong with tubes other than the cathode getting stripped. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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Mike Knudsen wrote:
In article , (Scott Dorsey) writes: Let's say you have a beam power tube that was used on an amplifier with a screen grid supply problem, and the screen grid drew current and burned completely away. There's nothing left any more. Agreed. Worse yet, a 6146 that got overdriven and the control grid has bruned away. No gain at all, but good emission. But I did ask "other than physical abuse", and maybe "electrical abuse" should have been included as well. Is it possible for a non-abused (in any way) tube to lose gain and performance, while its emission remains good? Sure, because you can get less dramatic examples of that sort of thing. Grids that sag a little bit, for instance. Yes, it's a mechanical failure, but it's a common one and it's not necessarily due to abuse. Deformed plates on power tubes are common too. Not including gas, which I believe the cheap tube testers can catch. Yes. BTW, I once owned a little grid emission tester, whihc I have seen mentioned here once or twice. Grid emission will kill your AGC line. --Mike K. Somewhere I have a free tube tester that Chicago Transformer gave me as a promotional item. It puts the tube filament across the AC line, with a neon bulb and resistor in series. If the filament is good, the neon bulb lights up, and the lamp doesn't pass enough current to light up, let alone damage, the filament. Totally useless, but a nifty conversation piece. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
Mike Knudsen wrote:
In article , (Scott Dorsey) writes: Let's say you have a beam power tube that was used on an amplifier with a screen grid supply problem, and the screen grid drew current and burned completely away. There's nothing left any more. Agreed. Worse yet, a 6146 that got overdriven and the control grid has bruned away. No gain at all, but good emission. But I did ask "other than physical abuse", and maybe "electrical abuse" should have been included as well. Is it possible for a non-abused (in any way) tube to lose gain and performance, while its emission remains good? Sure, because you can get less dramatic examples of that sort of thing. Grids that sag a little bit, for instance. Yes, it's a mechanical failure, but it's a common one and it's not necessarily due to abuse. Deformed plates on power tubes are common too. Not including gas, which I believe the cheap tube testers can catch. Yes. BTW, I once owned a little grid emission tester, whihc I have seen mentioned here once or twice. Grid emission will kill your AGC line. --Mike K. Somewhere I have a free tube tester that Chicago Transformer gave me as a promotional item. It puts the tube filament across the AC line, with a neon bulb and resistor in series. If the filament is good, the neon bulb lights up, and the lamp doesn't pass enough current to light up, let alone damage, the filament. Totally useless, but a nifty conversation piece. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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