First Watt SIT 5

[jeromelang]

How do people reconcile with the fact that first watts amps accept unbalanced inputs only and that they would be needed to be placed closed to upstream electronics to minimise transmission loss?

As a long time Pass user who has always placed the power amplifier closer to the loudspeakers driven by a long XLR cable from a balanced pass pre-amp, this create some no small problem.

I am looking for a lower powered, but purer Class A option from the x350.8

Will be operating the Aleph P (MK 2) at full volume with the 2 gain knobs at the minimum.

 

[Paul49720]

A couple of observations after listening to the 60.8 (which I’ve had for ~18 months) and swapping them out with the SIT 5:

1. The 60.8 just sounds a lot more solid state - still relatively warm but with relatively no bloom. Grainy and dull.

2. The SIT has much more holographic depth and texture with greater precision of detail across the sound stage (left to right, and front to back).

3. There seems to be a lot more musical information getting through which makes for greater realism and ultimately listenability. Just a magical sonic bloom. Anyone familiar with the other FW SIT amps knows their character, but they have never been available with this much power.

To be clear, I’ve been very impressed and pleased with the 60.8. While I’ve used the Pass XA25 as well as FW J2, F8, SIT 3, & SIT 4, the 60.8’s power made it the best all-rounder of that group even though all of the FW amps share the SIT 5’s superior sonics vs the PL amps. The trade-off has generally been power and with rock/pop/classical at elevated volumes the other FW amps simply lack the dynamics/overhead that come with more power.

The SIT 5 far more than any other FW bridges this gap and to such an extent that aside from crazy loud, the better sonics of the SIT are no longer qualified. It’s better across the range with all types of music. Better mid and highs are most evident but even tonality of the bass is better - again I cannot underscore how much more musical info gets through on the SIT vs the non-SIT Class-A Pass amp. It’s not a small thing despite the impressive starting point of the 60.8.

But given how important system synergy can be, my observations are all heard through Wilson Alexia 2 loudspeakers (and Nordost cabling). Some (including a very prominent reviewer) have been surprised by the positive synergy between FW with Wilson Audio. As many know, Wilson speakers are nominally a 4-ohm speaker and all but the SIT 4 make 30+ watts at that load and Nelson has frequently referenced that many are surprised by what only a few watts can produce. In short, all of these amp easily drive the speakers to reasonably loud listening levels although most are limited by their modest power. Again, I can only speak for my experience but the Alexia 2 as well as the Watt Puppy 7 have been a stellar match. Despite modest power, all of these FW amps have performed magically when paired with my speakers.

Hope this makes sense and there should be some forthcoming reviews to expand on the new FW.

Axel

Hi, thank you for posting your findings: serving 104dB efficiency horns, do you have a sense the SIT 4 would give all the musical sound and spatial character of the SIT 5 you describe ? (I presently use a 4w + 4w ADI tube SET (Yamamoto) which provides more than enough power through a TVC, typically using the first 3 - 5 indents of 24). ( EDIT: I quickly read one of the reviews which notes - "in the manual Nelson also mentions that we shouldn’t expect the two SITs to sound the same"). So there's an indication ! Thanks.

 

[Axel C]

Hi, thank you for posting your findings: serving 104dB efficiency horns, do you have a sense the SIT 4 would give all the musical sound and spatial character of the SIT 5 you describe ? (I presently use a 4w + 4w ADI tube SET (Yamamoto) which provides more than enough power through a TVC, typically using the first 3 - 5 indents of 24). ( EDIT: I quickly read one of the reviews which notes - "in the manual Nelson also mentions that we shouldn’t expect the two SITs to sound the same"). So there's an indication ! Thanks.

While there are differences to be sure, I think the recent SIT amps (3, 4, & 5) all share excellent sonic characteristics. I think each is terrific and believe the new Tokin based models take it a step further. IMO, both seem to have more oomph than the Semi South SIT-3. But to answer your question, yes I think the 4 gives a lot of what I like about the 5.

 

[MRubey]

Hi, thank you for posting your findings: serving 104dB efficiency horns, do you have a sense the SIT 4 would give all the musical sound and spatial character of the SIT 5 you describe ? (I presently use a 4w + 4w ADI tube SET (Yamamoto) which provides more than enough power through a TVC, typically using the first 3 - 5 indents of 24). ( EDIT: I quickly read one of the reviews which notes - "in the manual Nelson also mentions that we shouldn’t expect the two SITs to sound the same"). So there's an indication ! Thanks.

Right, slightly different topology. The SIT4 has the sonic signature that moved the needle well beyond where it had been with the 3, per the press. It is hoped the SIT5 captures enough of that. Sounds to me like people love it so it’s close enough.

From HiFi Knights
“The stereo version’s two key Tokin SITs operate in the Common-Source mode, where they supply both voltage and current gain. Each SIT5 mono houses a single SIT transistor that operates in the Common-Drain mode, where it only has to follow voltage, which secures lower output impedance, lower measured noise (30uV versus the SIT4’s 75uV) and higher bandwidth (5Hz-200KHz versus the SIT4’s 5Hz-80KHz). In the manual Nelson also mentions that we shouldn’t expect the two SITs to sound the same.”

FirstWatt SIT5 – HiFi Knights

This is the www.hifiknights.com review of FirstWatt SIT5 mono amplifier. Author: Dawid Grzyb. Enjoy!

hifiknights.com

 

[Alpha121]

Right, slightly different topology. The SIT4 has the sonic signature that moved the needle well beyond where it had been with the 3, per the press. It is hoped the SIT5 captures enough of that. Sounds to me like people love it so it’s close enough.

From HiFi Knights
“The stereo version’s two key Tokin SITs operate in the Common-Source mode, where they supply both voltage and current gain. Each SIT5 mono houses a single SIT transistor that operates in the Common-Drain mode, where it only has to follow voltage, which secures lower output impedance, lower measured noise (30uV versus the SIT4’s 75uV) and higher bandwidth (5Hz-200KHz versus the SIT4’s 5Hz-80KHz). In the manual Nelson also mentions that we shouldn’t expect the two SITs to sound the same.”

FirstWatt SIT5 – HiFi Knights

This is the www.hifiknights.com review of FirstWatt SIT5 mono amplifier. Author: Dawid Grzyb. Enjoy!

hifiknights.com

Do all these SITs have the negative phase second harmonic baked in?

Isn't that the part of the sound signature that is so appealing?

 

[Rumpole]

Do all these SITs have the negative phase second harmonic baked in?

Isn't that the part of the sound signature that is so appealing?

Looking at the FirstWatt webpage, the SIT-3 and SIT-4 do have the negative phase second harmonic, and I think they all do. In the SIT-3 manual Nelson says it is the signature that they preferred in the previous SIT amps. In his interview with Steve Guttenberg, Nelson said:

"but we saw to it that it had the negative phase character on that second because we found that that was that was an important element if you have (and this is a common perception, I can't say that everybody experiences the same thing) but a negative phase second harmonic tends to give an apparent expansion to the sound field so that things move out a little deeper and farther. If you go positive phase it kind of moves in and becomes a little more intimate maybe a little more detailed - it's totally any illusion but there it is, and we also found out that most of the customer base liked the negative phase"

There is no mention yet of the SIT-5 on the FirstWatt webpage. Is there any news on when they will be available? I really don't need another amplifier but I'd like to hear them.

Edit: The SIT-5 are on the webpage now