It depends on what your idea of 'optimal' is I'd guess Phil, where did the 3K5 figure come from out of interest? Explain yer innermost thoughts
CC Source in a Spud?
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#61 Re: CC Source in a Spud?
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#62 Re: CC Source in a Spud?
Ooh err, are you a psychoanalyst ?Dave the bass wrote: ↑Sat Jul 29, 2017 9:27 pmIt depends on what your idea of 'optimal' is I'd guess Phil, where did the 3K5 figure come from out of interest? Explain yer innermost thoughts
I estimated that a 3K5 loadlone would cross the loadlines at 90 degrees.
Don't laugh.
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#63 Re: CC Source in a Spud?
Yes, for tonight, I'm your Cycleanalyst!
Thats sound reasoning Phil, I see where you're coming from.
I made a picture for 3K5
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#64 Re: CC Source in a Spud?
Yes but you need to be further up in current, nearer the dissipation limit - then you don't get down into the 'mush' on the lower right hand end of the swing. So you need to have a different cathode resistor to change the operating point so the whole line can move up.
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#65 Re: CC Source in a Spud?
I thought there were procedures regarding current and voltage to establish fixed points on the axis and thence to plot the load line ?
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#66 Re: CC Source in a Spud?
Doink! Penny Drop! Thats why the 8/10/14K loads so sound lush and lovely....they don't enter that 'mush' region to the right so 'sharply' ... the high Z loadlines carry on in the more linear section.
Dagnabbit! We've done learning! Ta team!
EDIT. Double doink penny drop, that relates to the post Nick made about the looking at the dots and spacings too. Got it! today is a good day.
Dagnabbit! We've done learning! Ta team!
EDIT. Double doink penny drop, that relates to the post Nick made about the looking at the dots and spacings too. Got it! today is a good day.
Last edited by Dave the bass on Sat Jul 29, 2017 10:17 pm, edited 1 time in total.
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#67 Re: CC Source in a Spud?
"SOA"? Safe operating area? Is that what you're thinking of?
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#68 Re: CC Source in a Spud?
Yes - so for example get your starting point to 6W by going for 175V and 35mA, then draw the same line and it cuts through the grid lines a lot more evenly.
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#69 Re: CC Source in a Spud?
Fcuk knows, load lines are something I can understand on data sheets but I can't remember much about plotting them.Dave the bass wrote: ↑Sat Jul 29, 2017 10:15 pm
"SOA"? Safe operating area? Is that what you're thinking of?
The (very) old bwain is not too good at remembering things these days.
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#70 Re: CC Source in a Spud?
Yep, I see it, I see it.....but I refer the honourable Gent to the General Parameters box in the loadlines!IslandPink wrote: ↑Sat Jul 29, 2017 10:19 pm Yes - so for example get your starting point to 6W by going for 175V and 35mA, then draw the same line and it cuts through the grid lines a lot more evenly.
150V is quoted max for Anode... I have gone beyond that on 1 pair 6C45, no kittens died. There was also no audible 'gain' IMO.
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#71 Re: CC Source in a Spud?
That 150v is dc. You can go beyond that temporaly. Draw the max dissipation curve on the graph. Then find a idle point close ish to that. Or not but at least you know what area not to go into.
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#72 Re: CC Source in a Spud?
There's some stuff about load lines about half way down this page that might help, our Dave and our Phil?
http://simonsnewadventuresinhifi.blogsp ... e.html?m=1
http://simonsnewadventuresinhifi.blogsp ... e.html?m=1
#73 Re: CC Source in a Spud?
I would try 180v 35ma. Working the valve hard but worth a try. Maybe 2k5 load
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#74 Re: CC Source in a Spud?
Cooooooolio!
Max Anode dissipation is the pink arc on each set of Anode curves, 7.8W apparently. Thanks for the help all. OK, I'll revise the OP, I know its a bruiser of a valve and the Anode is made of stuff our-Ali eats for breakfast, I was being a soft southern Jessie as normal!
My reasoning for picking the 2V bias is it allows me to make full use of the swing available (in theory) from the source, made sense to me.
Max Anode dissipation is the pink arc on each set of Anode curves, 7.8W apparently. Thanks for the help all. OK, I'll revise the OP, I know its a bruiser of a valve and the Anode is made of stuff our-Ali eats for breakfast, I was being a soft southern Jessie as normal!
My reasoning for picking the 2V bias is it allows me to make full use of the swing available (in theory) from the source, made sense to me.
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#75 Re: CC Source in a Spud?
Nicks quiescent operating point would be at around -2v so thta box is ticked. You might want a low output impedance source though for best performance. A cf buffer if not.Dave the bass wrote: ↑Sun Jul 30, 2017 9:41 am Cooooooolio
My reasoning for picking the 2V bias is it allows me to make full use of the swing available (in theory) from the source, made sense to me.
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