First Watt SIT-4

[cjfrbw]

Double post because new product:

I will let you know when my Protos arrives!

Nelson Pass is releasing another First Watt single ended SIT, the SIT-4, made with Tokin SIT rather than his previous radar SIT. Amp is spec'd at 10 watts per channel, but the Tokin device has potential anode dissipation of hundreds of watts (radar SIT had anode dissipation of about 50 or 60 watts). It is both voltage and current amplifier with a mu type MOSFET binary with no feedback fronted by NP's favorite JFET buffer.

Likely due to the massive reserve of the Tokin device, the amp has a lazy distortion curve that goes to about 20 watts @ 5 percent or so distortion, and probably can punch out higher transients than that, so not so lightweight as it seems from basic specs. $5K, so maybe a 'poor man's' Aries Cerat triode transistor type.

NP is also planning monoblocks for heat sinking purposes to push the base power up to 20 watts or more per channel.

SIT-4 – www.firstwatt.com

The owner's manual can be downloaded here: SIT-4 Owner's Manual

www.firstwatt.com

Introducing the First Watt SIT-4 Power Amplifier - The Absolute Sound

Introducing the First Watt SIT-4 Power Amplifier - Tom Martin stops by the Refined Audio room to get a glimpse of First Watt's improved power amplifier, the SIT 4. It's a two-channel Class A, with a Triode tube-like character, it's equipped with Tokin SlTs rated at 400 watts and 30 amps and a...

www.theabsolutesound.com

I suspect this one will be a favorite of the low power high efficiency crowd, if it is anything like the single ended VFET Sony 2SK60 that I built from Pass DIY site.

Morricab's reports will be interesting on the AC units, but I have only read good things about them.

 

[Axel C]

I just received mine. It’s only played for a day but offhand two immediate observations. First, it’s a lot more powerful than the spec would indicate. I also have the J2, SIT3, and F8 and this one plays the loudest with the volume knob static. According to the FW website, its gain is higher than the others so that’s likely the contributor, but with only 10 wpc into 8 ohms (5 into 4 ohms) it's nonetheless impressive.
The other thing is it’s much hotter to the touch than the others. This is due to its higher bias but must be right on the edge of what is permissible.
Again, I’ve only been listening for the past 24 hours but right away it’s got that lovely SIT bloom. It’s replaced the XA25 and while I rate that one highly, the new SIT is noticeably more musical with much better depth and nuance especially in the mids and highs.
I intend to compare it back to back w the SIT3 later this week.
But suffice to say I think Nelson has another hit on his hands.

 

[cjfrbw]

Congrats. A new report after a couple of hundred hours of use would be welcome. However, I notice that the SIT products I have sound quite good even without a lot of warmup (as opposed to the M2 which doesn't come into form for at least an hour or two).

I gather NP may have a few SIT designs in the future with the Tokin SITs. I might buy one of the commercial products after we see what he rolls out.

 

[DetroitVinylRob]

monos to follow!

 

[the sound of Tao]

monos to follow!

SIT (5?) monos with maybe 20 watts plus a side… could be very interesting.

 

[aLLeARS]

Any further updates or reviews on the SIT-4?
Would love to see a picture of the inside.
Not much posted about this amp. Maybe there are not many in the field yet?

 

[godofwealth]

I have the J-2. It’s no SET killer, that’s for sure! I find its highs too grainy on my La Scalas, whereas my various SETs (45s, 300Bs, WE 421a) sound simply sublime. I hope the SIT-4 sounds better. Someone should compare it to a great 300B SET. The wattage looks about the same.