it is but it's not as simple as a SE bias circuit...if you look at the circuit you will see how crucial the balance is between the top and bottom of the out put pair.
mosfet biasing
#16 Re: mosfet biasing
There's nowhere you can be that isn't where you're meant to be
#17 Re: mosfet biasing
The grid transformer at your local supply point will tap up and down automatically as demand varies, so yes the voltage will wander. Depending on what industry is around you, some places will obviously vary more than others. There is not a lot close to me, so I'm fortunate to have pretty stable mains around 240.ed wrote: ↑Sat Aug 12, 2017 11:12 am
exactly so!...I think some sort of servo mechanism could be rigged, I even thought of an avr tracker but at the end of the day I want to have a play with a regenerator anyway...it may give up secrets with the other amps I have.
It was very interesting comparing notes with other builders of this circuit. I have deduced that the US mains is more stable thatn ours and it was interesting to find that one other UK builder had exactly the same bias problems as me...He came from lincolnshire which is not to far away, which may or may not be relevent. I naively think that the variations in mains are localised to sub stations or even street cabling and connectivity. Maybe Ali has an angle on this.
I do know that since the underground was relaid in our street(The leccy man said the previous line was getting too hot) We've had higher voltages.
Coincidentally I'm currently installing two new 90MVA transformers at a substation which are replacing two 60 odd year old 45MVA. Lot of this going on due to end of life cycle and so many wind-farms coming on line.
#18 Re: mosfet biasing
On a similar subject, I saw this the other day, which is a good thing IMHO,
http://www.linearsystems.com/lsnews/lsj689.html
http://www.linearsystems.com/lsnews/lsj689.html
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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#19 Re: mosfet biasing
I noticed that some of their JFETs appeared in the native libraries of LTspice a while ago... nice devices...Nick wrote: ↑Sat Aug 12, 2017 10:37 pm On a similar subject, I saw this the other day, which is a good thing IMHO,
http://www.linearsystems.com/lsnews/lsj689.html
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#20 Re: mosfet biasing
Low capacitance - nice !
"Once you find out ... the Circumstances ; then you can go out"
#21 Re: mosfet biasing
this may alter the playing field if we're lucky:
https://www.powersystemsdesign.com/arti ... on/8/11932
https://www.powersystemsdesign.com/arti ... on/8/11932
There's nowhere you can be that isn't where you're meant to be
#22 Re: mosfet biasing
or this:Nick wrote: ↑Sat Aug 12, 2017 10:37 pm On a similar subject, I saw this the other day, which is a good thing IMHO,
http://www.linearsystems.com/lsnews/lsj689.html
http://www.exicon.info/PDFs/ecx10n20.pdf
and its compliment
http://www.exicon.info/PDFs/ecx10p20.pdf
these are very tempting to try at the current price...
There's nowhere you can be that isn't where you're meant to be