Mike R. gave me in a private e-mail the hint that 1.75V/47000R gives a current of 0,000037234042553😀😀😀😀 A
So we have only 37 uV gate leakage. Under 100uV is o.k.
Long live Sun Pec!
And thanks Mike.....!
Yes i join Generg say thanks Mike for great beauty photos
of psu very appreciated
I'm happy to see that the Tokin SITs might be at least semi-legit. I might buy some, I might emulate them with big mosfets....
Generg have inspire Wrenchone to play with Tokin's.
After emulation amp name from Vfet it be V'fake ?
I like Your style

stop the blahblah!
it's time for you to build something with the 2SK82 , so much way to do it , single ended , pushpull, active load , choke load , resistor load ,bulb load . fixed bias , source resistor bias , etc...
you 'v got many days of happiness and headache with it.
and let the big boys play with Tokin Sit ( i'm not included)😀
Juanitox yes you have reason i am in and try push-pull,
and Ironamp first after choke maybe but actually is Aleph J.
I must wait to run Vfets hot and collect parts to be ready.
In spare find caps 4700uF | 385 Vcc for Ironamp prototype is to much ? Voltage normaly 160 Vcc it be around four time.
Thanks guys for useful informations
Best regards

Attachments
Last edited:
this caps are perfect for the job , better be safer than playing with fire like me with 35V power cap with 34V rail 😀
finally on the sound side the CSX1 ( single ended mod ) is the most pleasant of the 2SK82 sitamp i have built . the only concern is about the shy bass . bass are there but with no punch or power has i had with the inductor SITamp .. so i have two way to search , changing the 600ohm input transformer with a 10K 1:1 and search a better CCS load than the 2SJ28 ..
what about the bass with the Ironamp and it"s transformer output better damping i presume ?🙄
what about the bass with the Ironamp and it"s transformer output better damping i presume ?🙄
the only concern is about the shy bass . bass are there but with no punch or power has i had with the inductor SITamp
rolleyes:
Hi Juanitox
Do your psu filter caps banque is 120 000uF or more ?
What source impedance ? Hors or speakers is 4 Ohm ?
🙂
Attachments
what about the bass with the Ironamp and it"s transformer output better damping i presume ?🙄
Let's come back to Ironamp 😀
20Hz have -0,1 dB roll off so is great score for low frequency response. Damping ??
Two amp's Iron and Sony have possibility to configurate primary
maybe this is game to play.
Joint images extracted from Mr Rothacher video.
Anyway we must wait for precise informations from Mike : http://www.audiohobby.com/
Hope You have find solution.
Greeting 🙂
Attachments
-
E7E3ACBF-4A9C-4853-8FE0-550ED6346C19.JPG283.3 KB · Views: 150
-
245CD4F0-4689-4C80-9C1D-5445FAA648FF.JPG264 KB · Views: 138
-
50AA7E34-4552-4947-84C5-B0167470D5CE.JPG242.6 KB · Views: 122
-
790E0CBF-BF50-4BC2-AC14-C801391E196D.JPG236.7 KB · Views: 124
-
72C27677-4272-4606-96F8-CED8184ACDBE.JPG249 KB · Views: 128
-
5623432B-3A2B-446D-8AA4-5B362406A323.JPG234.1 KB · Views: 395
-
60D46C16-5223-4DCA-81D1-7C4D7038DF11.JPG216.1 KB · Views: 397
-
BFDE4D3E-1FFC-44D7-AE95-A1A3970A165D.JPG730.4 KB · Views: 159
Last edited:
my 1/2 CSX1 running fine , it"s time to go to attack the ironamp 🙂
my plan is to use only 2 MKP caps for it in a CLC power supply
500u 4H 500u will do the job ..
i have a 1:1 cinemag for input
i need to find a suitable 240V 80/90V power transfo
and the last but more important is the output power transfo..
i could go with edcor but to simple , i will try to find a EU Custom alternative.
with tube the common rule as 5x the anode/cathode resistance ..
what will be the best primary resistance value for the 2SK82 with 95V on it?
my plan is to use only 2 MKP caps for it in a CLC power supply
500u 4H 500u will do the job ..
i have a 1:1 cinemag for input
i need to find a suitable 240V 80/90V power transfo
and the last but more important is the output power transfo..
i could go with edcor but to simple , i will try to find a EU Custom alternative.
with tube the common rule as 5x the anode/cathode resistance ..
what will be the best primary resistance value for the 2SK82 with 95V on it?
my 1/2 CSX1 running fine , it"s time to go to attack the ironamp 🙂
and the last but more important is the output power transfo..
what will be the best primary resistance value for the 2SK82 with 95V on it?
Hi Juanitox
On schematic output transformer primary have 150 Ohms
with 8 Ohms secondaire but 100 V tension.
Imho if Mr Rothacher made this choice it was calculated
around best sweet spot , why make modifications ?
Lundahl distributor in France give you informations
contact him if interested correct prices :
Lundahl1
contact e-mail : info@ceresaudio.com
Nice you enjoy it sound from your 1/2 CSX1
Greetings
🙂

Attachments
i think michael use 150ohm because he find only this kind of primary on the market transformer avalaible. you can use a 7k transformer to load a 300B but it will not sound a good as a 5K or 3.5K.
that"s why i want to know the internal resistance of the 2SK82 at 95V to make the right custom made transformer 🙂
that"s why i want to know the internal resistance of the 2SK82 at 95V to make the right custom made transformer 🙂
i think michael use 150ohm because he find only this kind of primary on the market transformer avalaible.
From last update Michael say he was wait for specialy made
Edcor for this project output transformers 🙄
What is internal resistance ?
Simple ohm mesure between drain source et gate without courent , tension applied ?
Greetings 🙂
Last edited:
ok! i quit...
😱![]()
Sorry after verification this morning from update Ironamp video and is about customised INPUT transformer.
Probably output signal transformer data change too ....wait and see.

Attachments
it will be hard to find proper info , considering all posts with funny pictures and expression of unrestrained joy ....


it will be hard to find proper info , considering all posts with funny pictures and expression of unrestrained joy ....
![]()
damn right , i know a method to find tube internal resistance with the load lines but here with the 2SK82 we have no load lines on the high voltage side available in data sheet..
but we have soundhappy 😀
damn right , i know a method to find tube internal resistance with the load lines but here with the 2SK82 we have no load lines on the high voltage side available in data sheet..
but we have soundhappy 😀
I believe iilimzn already posted some snaps of curve tracer
even if he didn't , he's da Man to ask
Hi Mightyit will be hard to find proper info , considering all posts with funny pictures and expression of unrestrained joy ....
![]()
What is 2SK82 R=1 Ohm from "funny picture" data sheet post#151 ?
Handlebar mustache resistance for load lines ?
Wish You receivedamn right , i know a method to find tube internal resistance with the load lines but here with the 2SK82 we have no load lines on the high voltage side available in data sheet..


Last Mr Rothacher update video about curves was made for request of diyer named Jama from Spain
he have lab at home and work with Sony and Tokin Vfets too.
But i dont have any response from #150.but we have soundhappy 😀
This is frogy company who make your custom transformers ?
Could i ask name or link ?
Thanks ZM and Juanitox
Best regards 🙂
Attachments
Last edited:
- Home
- Amplifiers
- Pass Labs
- Ironamp Video Posted