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300b/GM70 Amp



 
 
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  #1 (permalink)  
Old August 8th 07, 09:37 AM posted to uk.rec.audio
tony sayer
external usenet poster
 
Posts: 2,042
Default 300b/GM70 Amp

In my earliest work days I designed colour TVs. We had an X-Ray
detector permanently covering the bench, because if the line output
valve got a few too many volts, and a bit too much current, its anode
would start to glow red, and X-Rays would come flooding out.


Wasn't that the shunt stabiliser that did that?.

Hence the metal can in some sets?..

--
Tony Sayer

  #2 (permalink)  
Old August 8th 07, 09:44 AM posted to uk.rec.audio
Don Pearce
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Posts: 1,822
Default 300b/GM70 Amp

On Wed, 8 Aug 2007 10:37:35 +0100, tony sayer
wrote:

In my earliest work days I designed colour TVs. We had an X-Ray
detector permanently covering the bench, because if the line output
valve got a few too many volts, and a bit too much current, its anode
would start to glow red, and X-Rays would come flooding out.


Wasn't that the shunt stabiliser that did that?.

Hence the metal can in some sets?..


No, definitely the line output valve. After a few minutes the problem
was self-curing though - a slight popping noise, and there was a neat
melted hole at the top of the glass envelope.

d

--
Pearce Consulting
http://www.pearce.uk.com
  #3 (permalink)  
Old August 8th 07, 11:18 AM posted to uk.rec.audio
Phil Allison
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Posts: 927
Default 300b/GM70 Amp


"Don Pearce Posturing Pommy Turd "

tony sayer

In my earliest work days I designed colour TVs. We had an X-Ray
detector permanently covering the bench, because if the line output
valve got a few too many volts, and a bit too much current, its anode
would start to glow red, and X-Rays would come flooding out.


Wasn't that the shunt stabiliser that did that?.

Hence the metal can in some sets?..


No, definitely the line output valve.




** Another absolute BLOODY LIE !!

Only tubes supplied with 16 kV or more are at all involved in x-ray
generation.





.......... Phil






  #4 (permalink)  
Old August 8th 07, 11:38 AM posted to uk.rec.audio
Nick Gorham
external usenet poster
 
Posts: 851
Default 300b/GM70 Amp

Phil Allison wrote:
"Don Pearce Posturing Pommy Turd "

tony sayer


In my earliest work days I designed colour TVs. We had an X-Ray
detector permanently covering the bench, because if the line output
valve got a few too many volts, and a bit too much current, its anode
would start to glow red, and X-Rays would come flooding out.

Wasn't that the shunt stabiliser that did that?.

Hence the metal can in some sets?..


No, definitely the line output valve.





** Another absolute BLOODY LIE !!

Only tubes supplied with 16 kV or more are at all involved in x-ray
generation.





......... Phil




I couldn't remember just what the voltage was, but I was sure its more
than 1kv.

--
Nick
  #5 (permalink)  
Old August 8th 07, 11:50 AM posted to uk.rec.audio
Don Pearce
external usenet poster
 
Posts: 1,822
Default 300b/GM70 Amp

On Wed, 08 Aug 2007 12:38:47 +0100, Nick Gorham
wrote:

Phil Allison wrote:
"Don Pearce Posturing Pommy Turd "

tony sayer


In my earliest work days I designed colour TVs. We had an X-Ray
detector permanently covering the bench, because if the line output
valve got a few too many volts, and a bit too much current, its anode
would start to glow red, and X-Rays would come flooding out.

Wasn't that the shunt stabiliser that did that?.

Hence the metal can in some sets?..

No, definitely the line output valve.





** Another absolute BLOODY LIE !!

Only tubes supplied with 16 kV or more are at all involved in x-ray
generation.





......... Phil




I couldn't remember just what the voltage was, but I was sure its more
than 1kv.


Well, this chap is aware of the phenomenon too

http://www.penders.cwc.net/otltbeht.html

Here too

http://www.r-type.org/exhib/aah0027.htm

d

--
Pearce Consulting
http://www.pearce.uk.com
  #6 (permalink)  
Old August 8th 07, 12:12 PM posted to uk.rec.audio
Phil Allison
external usenet poster
 
Posts: 927
Default Don Pearce = Stinking LIAR


"Don Pearce = ****ing LIAR "


No, definitely the line output valve.


** Another absolute BLOODY LIE !!

Only tubes supplied with 16 kV or more are at all involved in x-ray
generation.



Well, this chap is aware of the phenomenon too

http://www.penders.cwc.net/otltbeht.html

Here too

http://www.r-type.org/exhib/aah0027.htm




** Neither backs up the idiotic LIE posted by Don Pearce

The second link is for a regulator tube rated at 25kV !!!

Don Pearce = Lying Pommy Turd.






........ Phil



  #7 (permalink)  
Old August 8th 07, 12:29 PM posted to uk.rec.audio
Nick Gorham
external usenet poster
 
Posts: 851
Default 300b/GM70 Amp

Don Pearce wrote:
On Wed, 08 Aug 2007 12:38:47 +0100, Nick Gorham
wrote:


Phil Allison wrote:

"Don Pearce Posturing Pommy Turd "


tony sayer



In my earliest work days I designed colour TVs. We had an X-Ray
detector permanently covering the bench, because if the line output
valve got a few too many volts, and a bit too much current, its anode
would start to glow red, and X-Rays would come flooding out.

Wasn't that the shunt stabiliser that did that?.

Hence the metal can in some sets?..

No, definitely the line output valve.




** Another absolute BLOODY LIE !!

Only tubes supplied with 16 kV or more are at all involved in x-ray
generation.





......... Phil




I couldn't remember just what the voltage was, but I was sure its more
than 1kv.



Well, this chap is aware of the phenomenon too

http://www.penders.cwc.net/otltbeht.html


"The PD500 is also shielded. Not only does this valve dissipate 30 Watts
but it also emits X-Rays"

That will be the valve with its anode connected to the 25kv EHT line I
guess.

Here too

http://www.r-type.org/exhib/aah0027.htm


And that will be the valve with a max Va of 25kv

d


I am not suggesting that the valves mentioned can't produce x-rays, but
I am certain that a gm70 won't with 1kv on its anode.

--
Nick
  #8 (permalink)  
Old August 8th 07, 12:41 PM posted to uk.rec.audio
Don Pearce
external usenet poster
 
Posts: 1,822
Default 300b/GM70 Amp

On Wed, 08 Aug 2007 13:29:00 +0100, Nick Gorham
wrote:

Don Pearce wrote:
On Wed, 08 Aug 2007 12:38:47 +0100, Nick Gorham
wrote:


Phil Allison wrote:

"Don Pearce Posturing Pommy Turd "


tony sayer



In my earliest work days I designed colour TVs. We had an X-Ray
detector permanently covering the bench, because if the line output
valve got a few too many volts, and a bit too much current, its anode
would start to glow red, and X-Rays would come flooding out.

Wasn't that the shunt stabiliser that did that?.

Hence the metal can in some sets?..

No, definitely the line output valve.




** Another absolute BLOODY LIE !!

Only tubes supplied with 16 kV or more are at all involved in x-ray
generation.





......... Phil




I couldn't remember just what the voltage was, but I was sure its more
than 1kv.



Well, this chap is aware of the phenomenon too

http://www.penders.cwc.net/otltbeht.html


"The PD500 is also shielded. Not only does this valve dissipate 30 Watts
but it also emits X-Rays"

That will be the valve with its anode connected to the 25kv EHT line I
guess.

Here too

http://www.r-type.org/exhib/aah0027.htm


And that will be the valve with a max Va of 25kv

d


I am not suggesting that the valves mentioned can't produce x-rays, but
I am certain that a gm70 won't with 1kv on its anode.


Having just read that second link of mine, I find that Mullard called
the valve in question a line output valve, although it was used mainly
as an EHT stabilizer. 40 years have clearly fuddled my memory
slightly. I must ask nurse to tuck in my tartan blanket a bit tighter!

d

--
Pearce Consulting
http://www.pearce.uk.com
  #9 (permalink)  
Old August 8th 07, 02:47 PM posted to uk.rec.audio
tony sayer
external usenet poster
 
Posts: 2,042
Default 300b/GM70 Amp

In article , Nick Gorham
writes
Don Pearce wrote:
On Wed, 08 Aug 2007 12:38:47 +0100, Nick Gorham
wrote:


Phil Allison wrote:

"Don Pearce Posturing Pommy Turd "


tony sayer



In my earliest work days I designed colour TVs. We had an X-Ray
detector permanently covering the bench, because if the line output
valve got a few too many volts, and a bit too much current, its anode
would start to glow red, and X-Rays would come flooding out.

Wasn't that the shunt stabiliser that did that?.

Hence the metal can in some sets?..

No, definitely the line output valve.




** Another absolute BLOODY LIE !!

Only tubes supplied with 16 kV or more are at all involved in x-ray
generation.





......... Phil




I couldn't remember just what the voltage was, but I was sure its more
than 1kv.



Well, this chap is aware of the phenomenon too

http://www.penders.cwc.net/otltbeht.html


"The PD500 is also shielded. Not only does this valve dissipate 30 Watts
but it also emits X-Rays"

That will be the valve with its anode connected to the 25kv EHT line I
guess.


The CRT also emitted X rays but these were very low mainly reduced by
the glass and metal shield which also contained the degauss coil...

Here too

http://www.r-type.org/exhib/aah0027.htm


And that will be the valve with a max Va of 25kv

d


I am not suggesting that the valves mentioned can't produce x-rays, but
I am certain that a gm70 won't with 1kv on its anode.


--
Tony Sayer



  #10 (permalink)  
Old August 8th 07, 02:46 PM posted to uk.rec.audio
tony sayer
external usenet poster
 
Posts: 2,042
Default 300b/GM70 Amp

In article , Don Pearce
writes
On Wed, 8 Aug 2007 10:37:35 +0100, tony sayer
wrote:

In my earliest work days I designed colour TVs. We had an X-Ray
detector permanently covering the bench, because if the line output
valve got a few too many volts, and a bit too much current, its anode
would start to glow red, and X-Rays would come flooding out.


Wasn't that the shunt stabiliser that did that?.

Hence the metal can in some sets?..


No, definitely the line output valve. After a few minutes the problem
was self-curing though - a slight popping noise, and there was a neat
melted hole at the top of the glass envelope.

d


Beg to differ Don.. it was the PD 500 that was used for shunt
stabilisation in some Phillips chassis, notably the G6 and K7....
--
Tony Sayer

 




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