SissySIT

[August]

Oh I think they make good iron, only very pricey. Very interested to hear about your endavours with custom iron. Could you post the specifications needed?

 

[Zen Mod]

Cinemag CMOQ 4LPC is quadrifillar (as confirmed by guys from factory) wound thingie , each winding having 27Rdc and 1.5H (measured by your truly )

 

[damuffin]

Since nobody’s posting pictures I thought I’d add one. It,s a very compact layout with hardly any wire to connect bugs.

 

[Tea-Bag]

Since nobody’s posting pictures I thought I’d add one. It,s a very compact layout with hardly any wire to connect bugs.

Looks a lot like mine, but I have not even gotten the transformer ready.

 

[KweeSong Lim]

Just completed my SissySIT. Thanks to ZenMod. No issue building except for the output DC offset. I had to increase R8 by adding another 5k6 in series in order to reduce output offset to few millivolts. By SIT were from Pras1170. Vgs: 3.33v and 3.26v. IRFP9140 were from ZenMod. Vgs : 4.40,4.40v. I installed the power supply Capacitors and transformers in a separate chassis with the intention to reuse for future projects. Plug and play. Just build new amps without transformers in same chassis. Same $ and also effort to rebuild power supply with each new project.

 

[KweeSong Lim]

Here are some photo of my build

 

[MEPER]

Nice build!
What values have you "chosen" for RC snupper circuit at the universal PCB?
What about fuses on the DC side? …..do you have any from the big PSU chassis to the amp chassis? ….I guess it can be difficult with the large cap banks in the amp chassis? ….there is a lot of energy 🙂

 

[KweeSong Lim]

I use ultrafast On Semi MUR3040 with 0.1uF across each rectifier diode. No Fuses in the DC side. Only slow blow fuse on transformer primary side. No fuses from power supply side to amplier side. I use a soft start power on. Two 20 ohms NTC in’s series with 240V transformer primary. After a few seconds a relay shorts out the NTC. No issue with fuse blowing with. 3A slow blow fuse. Power supply consists of 2x 500VA ( one per channel) 8x22,000uF capacitance per channel. I use a 12V remote trigger from the amplifier side to turn on power to the power supply chassis. The most obvious difference with the added Capacitors bank is the sense of great Low frequency energy.

 

[Zen Mod]

Fugly!

🙂

and - sound?

 

[KweeSong Lim]

When first turned on. It was quite dark sounding. Unlike M2 where you hear very warm sweet sounding music upon first power up. After about an hour of play, things begin to brighten up and sounded warm and sweet. Haha. Maybe too many Capacitors to run in before sounding good. It’s singing very nice now. Lots of energy and big sound stage.

 

[Zen Mod]

and people are saying that amplifiers are anything else than variac between speaker and power supply



keep us informed , during burn in .......

 

[twitchie]

for THF51-S , body is drain ( no need for isolation for test , just keep heatsink electrically from other voltage potentials , other than + rail), fat protruding pin is source,while thin protruding pin is gate



again , any power N channel JFet , having ebough cojones , and having gate voltage in range of -1 to -3V6 is adequate for SissySIT circuit

if you sort your P channel mosfets , and use those with highish gate voltage (for -19 to -25V and Iq 1A8 to 2A) , in area of -4V5 , JFet can have even -4V gate voltage for intended conditions
have more questions , shoot

For measuring P-Channel mosfets, do we use this same circuit but with the opposite voltages (-24V and +9V) @ 1.8A Iq or do we use something like Papa's matching pdf? Would there be a difference matching at 15V (as in Papa's paper) or 24V?

 

[Zen Mod]

Papa's thingie

observe that mosfets are normaly off devices , while SITs are normally on devices

with mosfets , drain voltage isn't so decisive as with SITs , so use whatever you have , from 15 to 24Vdc

 

[twitchie]

planting seeds of knowledge

Thank you Mighty Zen Mod!

Just so that next new Greedy Boy and Girl can find it this is the matching procedure that Papa wrote:

Matching Devices by Nelson Pass

 

[nmiro]

Last year, I’ll lisened a Pass DefiSIT, a unique beast, to which I fell in love at first site, and afterwards, love became permanently, but sadly – it wasnt mine  .. Of course, the first question was - can you make for me something that plays like DefiSIT? The answer was - Maybe

The rest is history, quickly after, I connected T-Bed with Tokin SIT in the system, and as one of the first impressions that I recognized, was the same character of the sound that I heard with DefiSit. Today, the amplifier is done, and I am very happy with it.

This is due to the extraordinary musicality, which it has, the subtle presentation of the details, which it also has, and the realistic width and depth of the stage .. I compared SissySIT (serial number 001 🙂) with the ZM iteration of Pass2 J2 - Babelfish J2 which also great amplifier, mine former favorite from FW production .. todays favorite is SissySit, the best amp that I have in my system

The listening environment includes the Iron Pumpkin Bal / SE version, DC Tannoy in the MLTL box, Kuzma and Garrard 401 turntables, along with a number of top arms, MC pickups and SUT, as well as a digital part based on Cocktail Audio X50 and m2Tech Young II DAC

Heres, couple of pics:

An externally hosted image should be here but it was not working when we last tested it.

https://lh3.googleusercontent.com/J...q2pAbUb7sl9icZk4WdOH-B_lxubJm8=w1344-h1008-no

https://lh3.googleusercontent.com/c...UC0dpNdNlFvepNGCgco0GsUB6gua8v=w1344-h1008-no

 

[Zen Mod]

Last year, ......

pics are dead linked , so I'm reposting

 

[Mazeppa]

That black stack is envied by this Greedyboy.
A pre-amp with attitude, I dig it.

I had a '67 GTO that emanated a vibe like that back in the day.......

 

[pras1170]

Very beautiful

pics are dead linked , so I'm reposting

Very beautiful

 

[spavleski]

Hi,

Just to put some impression after having completed SissySIT, amplifier made by mighty ZenMod.

This is the real beast!

I have used to listen to Babelfish J2 and it is without any doubts one great amp.
This one is I would say even more natural sound which is been produced, although it is very hard to be believed...

 

[pras1170]

good