I wouldn't recommend the MoFo circuit for a SIT. Some other follower, perhaps. But If I had some 2SK180's lying around, I use them in a CS amp.
Ok not mofo scheme for sk180
which means "CS amp" Mr.Rothacher
I hate abbreviations.....
Ps: maybe I understood
does it mean common source?
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I wouldn't recommend the MoFo circuit for a SIT. Some other follower, perhaps. But If I had some 2SK180's lying around, I use them in a CS amp.
Hi MR,
Why would you not recommend MoFo SIT? I wonder if any technical reasons.
The prototype schematic of FW SIT-3 was CCS loaded common drain SIT, but NP has later replaced it with DEFiSIT.
I have tried choke loaded Sony VFT L'amp with both common source and common drain (MoFo like?), and I noticed the difference in sound signature between them, probably not only due to the obvious difference in damping factor.
MoFo benefits greatly from the high Drain resistance of the MOSFET in terms of output impedance and noise.
The Sony SITs don't offer much in the transconductance department and you wind up needing some gain in the front just to get unity. That's not to say NP might not have other ideas. I'm sure he does.
The Sony SITs don't offer much in the transconductance department and you wind up needing some gain in the front just to get unity. That's not to say NP might not have other ideas. I'm sure he does.
One more question to Mr Rothacher please
Ok Sony Vfet's have too little gain but is doable MoFo Sit with higher transductance Tokin's
like 2SK180 or THF-51 and big 2.5A ~ 3.5A rated choke ? Kind regards
Ok Sony Vfet's have too little gain but is doable MoFo Sit with higher transductance Tokin's
like 2SK180 or THF-51 and big 2.5A ~ 3.5A rated choke ? Kind regards
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MoFo benefits greatly from the high Drain resistance of the MOSFET in terms of output impedance and noise.
The Sony SITs don't offer much in the transconductance department and you wind up needing some gain in the front just to get unity. That's not to say NP might not have other ideas. I'm sure he does.
I see.
Do you think if any advantage to use SIT instead of MOSFET for follower amp?
Someone told me that the curves of MOSFET in MoFo are "already more ‘triodey’ than a triode.”.
I'm currently gathering parts for a L'Amp build. I'm going for the twin bulb version with a regulated adjustable supply based on the Zen v3 (cap multiplier). I'd like to generate the negative bias from the main transformer, like the schematic that popped up in post #1953 L'Amp: A simple SIT Amp Is there any further information on where that circuit originated from, and more importantly, if it actually works?
If you are talking about adjustable bias like SIT-1, I don't think the schematics has been officially released. For non-adjustable bias, extra a few ohm resister and a cap worked for me.
i want to try this thing but it gives me nightmare sometimes , if you short the speaker return accidentally to the chassis you will fry your speaker with 29V DC , is it possible to move the bypass cap on the output side so if you short the positive speaker cable to chassis or your hand you will have " only" 6V?
just an idea don't slap me
i want to try this thing but it gives me nightmare sometimes , if you short the speaker return accidentally to the chassis you will fry your speaker with 29V DC , is it possible to move the bypass cap on the output side so if you short the positive speaker cable to chassis or your hand you will have " only" 6V?
just an idea don't slap me
why so affraid my friend? why there would be a DC voltage on chassis? I only connect the chassis to IEC ground. my build has no issue
SIT L'Amp - Google Drive
