2sk77b and 2sk180 new projects

[woody]

I can understand how a sit with it's triode like curves can yield low distortion in a common source output stage but do they offer any advantage as a source follower? Another question about the 2sk180. If I run it as a common source amp with a 100mh choke any idea what the output impedience would be ?

 

[Nelson Pass]

I can understand how a sit with it's triode like curves can yield low distortion in a common source output stage but do they offer any advantage as a source follower? Another question about the 2sk180. If I run it as a common source amp with a 100mh choke any idea what the output impedience would be ?

Yes, they can do very well as Source Followers (Common Drain operation).

The attractive thing about the SITs, like the Triode, is that the varying
Vds can be used to cancel the characteristic of Ids/Vds. There are limits
to this, for example it is usually tuned to work with a particular load, and
loads which are reactive or out of an resistive impedance range will find
the effect compromised, as with a Triode in Common-Cathode or Common-Plate mode.

Drain resistance for the big SITs is on the order of 1 ohm, although this
varies by voltage and current. The slightly smaller 180 is likely to be
a bit higher - I have some but have not yet checked that.

 

[woody]

Thanks I may just have to try to build something and measure the output impedience.

 

[res07njc]

So, in other words... CD has a load line too?

bad papa!

 

[res07njc]

I guess the point of my poorly worded missive, is that does the same cancelation occur for a given quiescent point whether a device is used in common drain or common source mode? aka "sweet spot".

 

[Zen Mod]

......I have some ......

and then some more ........

 

[Nelson Pass]

I guess the point of my poorly worded missive, is that does the same cancelation occur for a given quiescent point whether a device is used in common drain or common source mode? aka "sweet spot".

You understand that the transistor does not know what mode it is used in.

Load line is not different from its viewpoint.

 

[Soundhappy]

雅马哈B-1旗舰功放，传说中的全SIT管放大器 - 科创

Interesting web page with 2SK77 and 2SK77B and First Watt SIT amp's

 

[Soundhappy]

N channel SIT cascoded by NPN semi, rare graph.
Curves like penthode

 

[woody]

Soundhappy, wonder how our friend the Ld1014d would work there with it's
rds of only ~ 5mohm it might be good driving a very low resistance like a ribbon tweeter without a matching transformer. But perhaps we would also modulate the cascode by using a drain resistor.

 

[Zen Mod]

some other interesting blogging there .......

川崎直列6缸发动机摩托车 - 科创

 

[Soundhappy]

理想放大管S45F323做的SIT管功放 - 科创
He builds push-pull mono blocks with Tokin TKS45F323 a pure unobtainium.
After start of this thread in 2015 my 2SK180 waits in bench drawer to wake up after the new exciting build article from Mr. Wiz.
Could be nice if happening at BAF 2019 it´s my hope..Please

 

[Soundhappy]

Soundhappy, wonder how our friend the Ld1014d would work there with it's
rds of only ~ 5mohm it might be good driving a very low resistance like a ribbon tweeter without a matching transformer. But perhaps we would also modulate the cascode by using a drain resistor.

Hi Woody
I am confident Papa know how to get smooth triode sound with transparency.
Maybe with surprise topology tricks Kind regards

edit : Imagine Zen Mod do burn the sausages one more time in San Francisco

 

[Zen Mod]

they were burned on grill , while mine were nicely cooked on stone



of all Greedy boys who tried them ( stoned) , half was thrilled , while other half still preferred burned ....... stoned were too funny for them

 

[WBS]

Hmmm... Stoned dogs... the mind reels!

 

[Soundhappy]

, while mine were nicely cooked on stone

Zen Mon class A amplifiers sound have subtile taste included

 

[Soundhappy]

of all Greedy boys who tried them ( stoned) , half was thrilled , while other half still preferred burned

This year can be one day burned and next day stoned by Zen Moon Zen Mood aka Zen Mod.
Regular DIYers remember bring soldering station for Saturday workshop.
BurningAmp : The annual audio DIY event at Fort Mason, San Francisco CA for audiophiles who make their own equipment, components for amps, speakers, and parts. | The annual audio DIY event at Fort Mason, San Francisco CA for audiophiles who make their own equipment, components for amps, speakers, and parts.
Time is flying

 

[Soundhappy]

This thread start january 2015 about NEW 2SK180 projects but today in august 2019 is the NEW OLD STOCK projects thread
BAF 2019 maybe ?

 

[Zen Mod]

with any of your big SITs - you can build Papa's 2SK77B amp , presented few years ago on BAF

can't remember which year exactly

in same vid Pa gave us poor man's iteration with Mosfet pucks

so , I believe that we cannot say that Pa left us flappin' in da breeze

 

[Ben Mah]

It was BAF2015. Here is the video:

YouTube