As a guess from the photo (correct me if I am wrong), with the foil, the plastic zip ties, and other related items, it should be from Tokyo, Japan purchased from Watanabe-san (mine came much the same style and packaging).
Yes indeed, Tomo-san. Well recommended as he was incredibly responsive and provided guidance and offered the fitting kits as well. Took just over a week to arrive in the U.K.
I also ordered a matched quad 2SK180s so have an abundance of SITs for what I hope will be some very special applications.
Yes pico, Tomo is the best to deal with on these items. I have mine from him - genuine NOS and cheaper as well.
Btw, "pras" here in the thread is also another trust source (Nelson Pass has mentioned this a few times and he has purchased from her too). She has a more wider variety of SIT devices. I believe Zen Mod might have also purchased from her, if I recall correctly.
Her devices are pulled parts from commercial and industrial machinery from the looks of it. Used pulls ought not be a concern as she tests, roughly matches, and is careful with her work. The devices themselves are rated for hundreds of volts, well built, and are quite robust.
A fellow diy'er near me has purchased from Pras for this upcoming project via her aliexpress store. Other than scrubbing to remove some light staining and blow torching off (yes, he used a small propane torch 😱 ... he's more hollow state so maybe that explains it...) some old solder left on the leads, his THF-51 devices were as good looking as mine from Tomo and maybe even a little better. Mine are unused NOS but have some yellow brown stains where the leads are potted.
Her devices are pulled parts from commercial and industrial machinery from the looks of it. Used pulls ought not be a concern as she tests, roughly matches, and is careful with her work. The devices themselves are rated for hundreds of volts, well built, and are quite robust.
A fellow diy'er near me has purchased from Pras for this upcoming project via her aliexpress store. Other than scrubbing to remove some light staining and blow torching off (yes, he used a small propane torch 😱 ... he's more hollow state so maybe that explains it...) some old solder left on the leads, his THF-51 devices were as good looking as mine from Tomo and maybe even a little better. Mine are unused NOS but have some yellow brown stains where the leads are potted.
From a durability point of view do you have any favourite electrolytic caps for output duties?
"So why not a push-pull circuit for 50 or 60 Watts?"
It seems that we already have a design that may be adaptable to such. I might be crazy, but the F6 looks like a good candidate for a simple amp design that could accommodate a quad of N-type SITs for the two channels. They could be roughly matched, or less so. Even 2SK182ES on top and THF-51S on bottom or vice versa could add some harmonic flavor to the mix..
The input buffer needs to handle higher voltage rails. (Say +/– 30V to 36V) So either a cascode version of the simple JFet buffer or a modified Diamond, aka Austin, buffer similar to what I used in my F6 would fit the bill.
We certainly have some big chassis that should be up to the task.
It seems that we already have a design that may be adaptable to such. I might be crazy, but the F6 looks like a good candidate for a simple amp design that could accommodate a quad of N-type SITs for the two channels. They could be roughly matched, or less so. Even 2SK182ES on top and THF-51S on bottom or vice versa could add some harmonic flavor to the mix..
The input buffer needs to handle higher voltage rails. (Say +/– 30V to 36V) So either a cascode version of the simple JFet buffer or a modified Diamond, aka Austin, buffer similar to what I used in my F6 would fit the bill.
We certainly have some big chassis that should be up to the task.
F6 will do better with mosfets with higher drain impedances.
That's my recollection of papa's observations and the reason for choosing irfp240 over semisouth.
The SIT's have even lower drain impedances.
That's my recollection of papa's observations and the reason for choosing irfp240 over semisouth.
The SIT's have even lower drain impedances.
mark my words :
regarding push-pull :you already have DEF circuit - you'll hardly ever find one, being better bunch of compromises, when SIT is in case
I did some sims, didn't felt urge to try it in vivo - two same sex SITs in PP - too much of SITiness, for my taste
regarding push-pull :you already have DEF circuit - you'll hardly ever find one, being better bunch of compromises, when SIT is in case
I did some sims, didn't felt urge to try it in vivo - two same sex SITs in PP - too much of SITiness, for my taste
In case of perfectly matched SITs, uSIT will eat the even harmonic produced by bSIT and vice versa, a SIT ouroboros, and may leave you stuck with the odd harmonics.
In case of not perfectly matched SIT, you can have one channel with neg phase H2 while the other being positive, which may also drift with heatsink temperature, supply voltage or music being played back. In short an unpredictable with possibly unstable drifting presentation.
Perhaps an F6 topology fitted with upper SIT and bottom Mosfet would be a safer bet.
ok, all roads lead to Rome, but that one not interesting for this Roman
Sirens and Harpies already sided me to DEF route, heavily
Sirens and Harpies already sided me to DEF route, heavily
Got my pair back a ways back at "only" $60 ea. piece. Seemed like a fortune back then. But if I'm happy to have them at 60 then what's $30 more!
Tokin 51n or SK180 and Nemesis
Late in the game with the SIT but now have several of Tokin 51n and a couple of SK180. Very low on know how on these SIT however...
Thinking about the L'Amp, ordered the chokes & waiting..
And I wonder whether I could use these in the Nemesis amp. The SIT version of that amp used the Pass SIT as far as I know and I have no idea, at present, how to adjust that schematic for the Tokin 51N, or the SK180 I ordered from mr. Watanabe.
Late in the game with the SIT but now have several of Tokin 51n and a couple of SK180. Very low on know how on these SIT however...
Thinking about the L'Amp, ordered the chokes & waiting..
And I wonder whether I could use these in the Nemesis amp. The SIT version of that amp used the Pass SIT as far as I know and I have no idea, at present, how to adjust that schematic for the Tokin 51N, or the SK180 I ordered from mr. Watanabe.
Hi van Doorn, I have heard the original Nemesis, with that marvelous output transformer, in Paris at the Audiophile shop. The best I ever heard. 🙂
The implementation with a 32-8 ohm transformer can be great - I modelled it. However, a real-life transformer is harder to find.
Looks like we. Are on the same stage here.
The implementation with a 32-8 ohm transformer can be great - I modelled it. However, a real-life transformer is harder to find.
- I have asked some aliex shops for this; but you won’t know what the quality will be (mediocre to good? But not great?). I have not come across recommendations here on the forum yet;
- as regards chokes, common opinion is using the Hammond 193 that is available in Holland somewhere.
- I have two power/HV chokes. Will use that first.
Looks like we. Are on the same stage here.
mark my words :
regarding push-pull :you already have DEF circuit - you'll hardly ever find one, being better bunch of compromises, when SIT is in case
I did some sims, didn't felt urge to try it in vivo - two same sex SITs in PP - too much of SITiness, for my taste
Just curious for the sake of learning, what does too much SITiness look like? It would be interesting to see your sim results.
I'm not sure that I want all that complication in quasicomplementary arrangement, just to fight against cancellation of 2nd harmonic (to retrieve it back), when Pa gave us DEF recipe, which is tickin' all boxes, at least mine
that was meaning of too much of SITiness , one SITiness cancelling other, so resulting in not enough SITiness at output
I didn't save these sims, as they led me where I wasn't interested to go
that was meaning of too much of SITiness , one SITiness cancelling other, so resulting in not enough SITiness at output
I didn't save these sims, as they led me where I wasn't interested to go
I have ordered a pair of J&K Audio Design's take on the Tango FG-50S output transformers. There is a 4 to 8 week wait on these so maybe I'll have them by late June. I have some SITs that I will try them with.
I have been several times at the maison de l áudiophile too, what an amazing
experience. Inspiration for a lifetime...
I built their 300b and 50w+50w class A amp
and now and try to bring a Nemesis in my home
I will get the J&K 1:1 copy of the original Tango if i can get it to work with a chinese transformed SE and 'designed' for this application with a transistor
A NemeSIT is definitely interesting. Being able to invert polarity will give good harmonics "direction" if I understand the diagrams that Nelson Pass gave.
Still I am sure a premium transformer is half the quality of the build.
I remember there was a French manufaturer involved too in the build of the Nemesis.
NameitSITse or something else if you like.
