L'Amp: A simple SIT Amp

[plasnu]

what's stopping you?

once i connected my dac with srpp ouput to SIT L'amp directly to Alpair 10p, 1 channel only and very loud. tested on slow music Ingram Washington ‎– What A Difference A Day Makes

but for sure it's not practical 😀

🙂

hmm, I'm still learning... CCDA tube front end in Soundhappy's schematics also looks interesting.

 

[gadut]

🙂

hmm, I'm still learning... CCDA tube front end in Soundhappy's schematics also looks interesting.

i prefer this version of Luminaria where input stage use 5687 tube 😉

 

[plasnu]

i prefer this version of Luminaria where input stage use 5687 tube 😉

I have never seen this before. Thank you.

 

[stormpetrel]

Hello everybody,

This is my first message on this forum (at least since 11 years). There is so much information on this website nowadays, it makes things a bit confusing.... So please let me know if I'm posting my message in the wrong place or if I'm asking a question already answered.

I'm currently building a Zen9 but since few days I have been contaminated with the SIT virus, so I'm building now both a Zen9 and a "L'Amp" and they will both share the same power supply.

The SIT amp is based on a 2SK180 SIT which runs with a pair of 2SK170/2SJ74 upfront.

I have also added a tracking Aleph CCS, same as the one designed by Nelson for the ZEN9 / Aleph amplifier. And sure I have also added the cap multiplier (There are such nice goodies in the Zen 9 design, it would be a pity to not implement them on the "l'amp.")

I did a quick check with LTspice using the spice model 2SK180 made by Le Createur de L'Amp", and the voltage gain jump from 4x (with the 23 Ohm resistor and a +83V power supply source) to 6x with the "tracking aleph CCS" powered at 60V . This is a nice expected improvement, (both amps operate on the same sweet spot VDS=37V ID=2.1A VG=-6.33V)

I was wondering if somebody used the Aleph as a CCS for the "L'amp". I have seen somewhere in the 300 pages of this thread a CCS based on the 4N37 optocoupler but no the tracking Aleph CCS.

Do I miss something? Any reason why people avoided this nice CCS or should I replace my glasses an reread the 300 pages?

here is a copy of the schematic:

SIT amplifier base on l'Amp + tracking Aleph CCS V DF,


And the bode plot
SIT amp + Aleph CCS bode plot by DF

Next step will be the THD curves with and without aleph CCS.
The real stuff might differ significantly from the spice model anyway.

PS: Despite my kiwi flag, English is not my native language (I'm a Kiwi with a very strong french accent) so sorry if my spelling or if my bad sentences hurt your eyes!

 

[Zen Mod]

just go for it

one thing - when trying for gain in simulator , you had load on output?

 

[plasnu]

I was wondering if somebody used the Aleph as a CCS for the "L'amp". I have seen somewhere in the 300 pages of this thread a CCS based on the 4N37 optocoupler but no the tracking Aleph CCS.

Do I miss something? Any reason why people avoided this nice CCS or should I replace my glasses an reread the 300 pages?

I also have not seen someone realized SIT + Aleph CCS. Since I really like my AJ and L'amp, I'm very interested in this. 🙂

 

[Zen Mod]

Papa's Shade pucks amp from BAF is close enough

change Mu stage above to Aleph and that's it

change lower stage to SIT , that's it

both amps covered in same lecture , see Oootoobe

 

[stormpetrel]

just go for it

one thing - when trying for gain in simulator , you had load on output?

Yes. A 8 Ohm resistor

 

[stormpetrel]

Papa's Shade pucks amp from BAF is close enough

change Mu stage above to Aleph and that's it

change lower stage to SIT , that's it

both amps covered in same lecture , see Oootoobe

I was not aware about the Papa's video on youtube (my interest in class A solid state amp started 2 weeks ago) .

I have watched one of them this morning with my first coffee.... (the one with the cascode). Wow! It was like being in a electronician Walhalla !

 

[Zen Mod]

just be careful , when dealing with anything Papa

more than once I needed to clean both my screen and my nose of coffee , just because of him

 

[stormpetrel]

Wise advice! Thank you!

 

[stormpetrel]

I have run some THD simulation with LTspice today, with and without the aleph CCS.

I found a THD of ~0.7% @1W/1kHz with the 23Ohm resistor powered @ 83V, and 0.6% with the Aleph CCS.

Michael measured a THD of ~0.16% @1W/1kHz on his 2SK180 light bulb amp(same sweet spot Vds=37/Id=2.1A).

It is good to see that the Aleph CCS improves the THD a bit however I'm not too much concerned by the discrepancy between the model results and his measurements. Models are models...

 

[juanitox]

i'm running mt CCS sitamp with with 60V B+ and 30V on the Sit
is the 50/50 of dissipation between CCS and Vfet the magic point or is there another golden ratio ?

 

[stormpetrel]

The Aleph CCS (without the AC feedback) reduces the power consumption by 50% but also the distortion & noise . Papa said in ZV2, this was an optimal ratio for a class A amplifier. It should be true for any well designed CCS and SIT amplifier too!

 

[Soundhappy]

L'Amp or De-Lite or maybe not 😉

井筒香奈江　氷の世界

Blue light 😀

 

[Zen Mod]

whazzat?

 

[PierreQuiRoule]

+1

 

[Soundhappy]

Auditors were very curious....such enigmatic turquoise light bulb ??

 

[R-K Rønningstad]

Is that a Cello Palette preamp?

 

[Soundhappy]

On first photo the silver colour front plate on the wood rack looks the same:
Cello Palette Preamplifier | Stereophile.com
R-K You are the expert 🙂 Bravo!