On Sunday, 16 August 2020 15:31:58 UTC+1, Phool Allison  wrote:
> Tabby the Fucking Idiot wrote:
> 
> ===============================
> 
> > > ==============
> > > > 
> > > > All valves require heater power to conduct. 
> > > > All only conduct once the heater is hot.
> > 
> > > ** Shame about cold cathode tubes then ...
> > 
> > The OP asked for an introduction,
> 
> **  Not bullshit.
> 
> 
> 
> 
> > > ** By pure coincidence, I was looking at max plate I in relation to 6L6GC and 6550 types this morning. 
> > > 
> > > The figures are not published in the max listings but some info can be gleaned from sets of graphs. Max available plate current is a function mostly of screen volts, plus any inherent limits on cathode emission - which varies with tube condition and brand. 
> > > 
> > > For Russian made examples in good condition I found max plate I to be 400 and 750 mA respectively, long as the screen supply was 450V or more. 
> > > 
> > > However, a used US made Sylvania 6L6GC was able to pass 550 mA under the same ( 50Hz pulse) test conditions. 
> > > 
> > > See link for details of my test set up: 
> > > 
> > > https://sound-au.com/project165.htm 
> > > 
> > > 
> > 
> > I_max degrades over the valve's lifetime, and the harder you 
> > push it the less well it lasts. Hence in some apps the valves
> > last & last, and in some harder pushed designs they don't. 
> > Valves effectively have guidelines.
> >
> 
> ** Shame autistic *raving lunatics* like you do not have any. 
> 
> I sincerely look forward to you imminent death, as does everyone unlucky enough to know you.  
>   
> 
> 
> .....  Phil

What's wrong with this one, anyone know? 

On 10/08/2020 11:14 am, bitrex wrote:
> On 8/9/2020 6:21 PM, Tim Williams wrote:
>> Hard to go wrong with good old RDH4,
>> http://www.tubebooks.org/Books/RDH4.pdf
>>
>> May be a little on the heavy side if you're more generally beginner, 
>> than an active designer and just unfamiliar with tubes in particular.
>>
>> Also plenty of articles and web pages by varying degrees of experts, 
>> fans and nuts.� Tubecad comes to mind as one of the generally 
>> informative ones. Downside is, the audioph{ile|ool} community won't 
>> give the most practical or representative picture of things, so keep 
>> that in mind.
>>
>> Tim
>>
> 
> An RDH4 alternative from the time period that's a bit more compact but 
> covers the important topics:
> 
> <https://www.amazon.com/Electron-tube-Circuits-Samuel-Seely/dp/B00005VRTP>

looking into it. thanks

On 10/08/2020 8:21 am, Tim Williams wrote:
> Hard to go wrong with good old RDH4,
> http://www.tubebooks.org/Books/RDH4.pdf
> 
> May be a little on the heavy side if you're more generally beginner, 
> than an active designer and just unfamiliar with tubes in particular.
> 
> Also plenty of articles and web pages by varying degrees of experts, 
> fans and nuts.� Tubecad comes to mind as one of the generally 
> informative ones. Downside is, the audioph{ile|ool} community won't give 
> the most practical or representative picture of things, so keep that in 
> mind.
> 
> Tim
> 

RDH4 looks very good. Thanks. Now to stoke up the fireplace and sit down 
with a coffee....HOLY CRAP 1500+ pages!

Seriously, thanks.

On 10/08/2020 7:20 am, boB wrote:
> On Mon, 10 Aug 2020 07:06:13 +1000, david eather
> <eathDELETEer@tpg.com.au> wrote:
> 
>> suggestions please
>> TIA
> 
> 
> Lots of old books scanned online.
> 
> Search for vacuum tube design or similar into Google etc...
> 
> www.archive.org   will have many books I believe.
> 
> 
> 
> 

many, many, books. I didn't know about archive.org
. Thanks

Tabby the Fucking Idiot wrote:

===============================

> > ==============
> > > 
> > > All valves require heater power to conduct. 
> > > All only conduct once the heater is hot.
> 
> > ** Shame about cold cathode tubes then ...
> 
> The OP asked for an introduction,

**  Not bullshit.




> > ** By pure coincidence, I was looking at max plate I in relation to 6L6GC and 6550 types this morning. 
> > 
> > The figures are not published in the max listings but some info can be gleaned from sets of graphs. Max available plate current is a function mostly of screen volts, plus any inherent limits on cathode emission - which varies with tube condition and brand. 
> > 
> > For Russian made examples in good condition I found max plate I to be 400 and 750 mA respectively, long as the screen supply was 450V or more. 
> > 
> > However, a used US made Sylvania 6L6GC was able to pass 550 mA under the same ( 50Hz pulse) test conditions. 
> > 
> > See link for details of my test set up: 
> > 
> > https://sound-au.com/project165.htm 
> > 
> > 
> 
> I_max degrades over the valve's lifetime, and the harder you 
> push it the less well it lasts. Hence in some apps the valves
> last & last, and in some harder pushed designs they don't. 
> Valves effectively have guidelines.
>

** Shame autistic *raving lunatics* like you do not have any. 

I sincerely look forward to you imminent death, as does everyone unlucky enough to know you.  
  


.....  Phil 

On Sunday, 16 August 2020 at 05:42:04 UTC+1, palli...@gmail.com wrote:
> Tabby wrote: 
> 
> ==============
> > 
> > All valves require heater power to conduct. 
> > All only conduct once the heater is hot.

> ** Shame about cold cathode tubes then ...

The OP asked for an introduction , obviously there is far more to the subject. 


> > Current limiting under overload 
> > triode: same as a fet, but high Va usually required 
> > pentode: as triode but the screen grid requires a fair bit 
> > of +ve V at lowish i. 
> >
> ** By pure coincidence, I was looking at max plate I in relation to 6L6GC and 6550 types this morning. 
> 
> The figures are not published in the max listings but some info can be gleaned from sets of graphs. Max available plate current is a function mostly of screen volts, plus any inherent limits on cathode emission - which varies with tube condition and brand. 
> 
> For Russian made examples in good condition I found max plate I to be 400 and 750 mA respectively, long as the screen supply was 450V or more. 
> 
> However, a used US made Sylvania 6L6GC was able to pass 550 mA under the same ( 50Hz pulse) test conditions. 
> 
> See link for details of my test set up: 
> 
> https://sound-au.com/project165.htm 
> 
> 
> ..... Phil

I_max degrades over the valve's lifetime, and the harder you push it the less well it lasts. Hence in some apps the valves last & last, and in some harder pushed designs they don't. Valves effectively have guidelines.


NT

Tabby wrote:

==============
> 
> All valves require heater power to conduct.
> All only conduct once the heater is hot.

** Shame about cold cathode tubes then ... 

> Current limiting under overload
> triode: same as a fet, but high Va usually required
> pentode: as triode but the screen grid requires a fair bit
> of +ve V at lowish i.
>

** By pure coincidence, I was looking at max plate I in relation to 6L6GC and 6550 types this morning.  

The figures are not published in the max listings but some info can be gleaned from sets of graphs. Max available plate current is a function mostly of screen volts, plus any inherent limits on cathode emission - which varies with tube condition and brand. 

For Russian made examples in good condition I found max plate I to be 400 and 750 mA respectively, long as the screen supply was 450V or more.  

However, a used US made Sylvania 6L6GC was able to pass 550 mA under the same ( 50Hz pulse) test conditions.  

See link for details of my test set up:

https://sound-au.com/project165.htm


.....   Phil 
 

On Sunday, 16 August 2020 at 00:45:53 UTC+1, palli...@gmail.com wrote:
> david eather wrote: 
> 
> ================ 
> > 
> > >>> ** Your Q is way too broad - the topic of tubes is ENORMOUS while current production involves only a few popular audio types. 
> > >>> 
> > >>> FFS tell us what you ACTUALLY wish to know about. 
> > >>> 
> > >> 
> >
> > OK maybe this helps. I would like to learn enough so I can look at a 
> > schematic of basic valve circuits and be able to work out what it is and 
> > what it does. 
> > 
> >
> ** So you are never going to answer the question. 
> 
> 
> 
> ..... Phil

All valves require heater power to conduct. All only conduct once the heater is hot.
diode: lower i, much higher Vf than silicon. Current limiting under overload
triode: same as a fet, but high Va usually required
pentode: as triode but the screen grid requires a fair bit of +ve V at lowish i. Pentodes have less Cag & more gain.
Hexode, pentagrid etc: bit more complex.


NT

david eather wrote:

================
>
> >>> ** Your Q is way too broad - the topic of tubes is ENORMOUS while current production involves only a few popular audio types.
> >>>
> >>> FFS tell us what you ACTUALLY wish to know about.
> >>>
> >>
>
> OK maybe this helps. I would like to learn enough so I can look at a 
> schematic of basic valve circuits and be able to work out what it is and 
> what it does.
>
>

** So you are never going to answer the question. 



.....  Phil 

On 14/08/2020 4:05 pm, Phil Allison wrote:
> david eather who refuses to answer a simple question wrote:
> 
> ===========================================================
> 
>>> ** Your Q is way too broad - the topic of tubes is ENORMOUS while current production involves only a few popular audio types.
>>>
>>> FFS tell us what you ACTUALLY wish to know about.
>>>
>>
>> A very fair question.
> 
> 
> ** Which is still going unanswered.
> 
>   
>> As a young lad I had no contact with valves. At uni I had no need to
>> know anything about them and studiously (is that even possible?) avoided
>> them. Now at home much more because of CV19, I have lots of spare time
>> and while it is not going to be a source of any income I would like to
>> fill at least some of my ignorance.
>>
> 
> ** And you imagine reading a book will do that ?
> 
> 
>> So I am looking for a good general introductory book on the subject.
> 
> 
> ** What subject is that  ?
> 
>     We cannot reads your mind.
> 
> 
>> see lots of recommendations which I will go through 'till I find
>> something of the right level.
> 
> 
> ** So you are not going to answer the Q at all ?
> 
>    Wot a PIA you are.
> 
> 
> .....  Phil
> 
> 

OK maybe this helps. I would like to learn enough so I can look at a 
schematic of basic valve circuits and be able to work out what it is and 
what it does.

Also very important: You didn't like the road runner joke?