Ultimate Audio Playback => Chatter and forum related stuff => Topic started by: manisandher on March 14, 2021, 01:12:17 pm

Title: NOS1 driving speakers directly... almost
Post by: manisandher on March 14, 2021, 01:12:17 pm
I'd been intrigued by the First Watt F4 amp since it came out quite a while ago now. I say 'amp', but it's actaully a class A 'impedance converter' with no voltage gain or feedback.

With a run of only 100 in total (each assembled by Nelson Pass himself), I never thought I'd get around to ever hearing one, let alone owning one. In NP's own words, "Overall, it is one of the best sounding amplifiers, and if you can live with unity voltage gain in your amplifier, it is possibly your best choice."

So, I jumped at the opportunity last year of buying not one, but two F4s, to use as balanced monos for my office system. But only yesterday did I finally get around to hooking my (non-B75) NOS1 up to them.

So, how does the NOS1 sound driving the speakers pretty much as directly as it's possible to get?

It's a really interesting sound. Zero brightness, with a more 'wooden' (as opposed to 'metallic') sound. No element of the sound brings particular attention to itself. Really beautiful midrange detail though. And totally integrated from top to bottom.

In many ways, a sort of 'boring' sound, because there's not a lot to say about any one aspect of it. And yet, really, really lovely to listen to. It's how I always hoped tubed amps would sound, but never actually did in my experience.

And all this with a 'mere' Lush^2! (Peter, there may be a new order coming your way  :).)

Just thought I'd share...


Title: Re: NOS1 driving speakers directly... almost
Post by: PeterSt on March 14, 2021, 01:20:02 pm

Mani - wow. But are these speakers so sensitive then ?

Keep in touch with that "boring" sound. I mean, this can end up to be literal. I have that quite often (with wrong settings or wrong cables) and then each 6+ minute track starts to sound the same all through. So as soon as that starts to occur, you are on the wrong track.

So the current must be OK. But I wonder what a just a tad to low voltage (is volume output) will do to the sound. Maybe nothing.

Interesting !

Title: Re: NOS1 driving speakers directly... almost
Post by: manisandher on March 14, 2021, 01:32:07 pm
The speakers are spec'd at 97dB/W@1m. The F4 mono needs a 10V swing to achieve its full 100W output into 8 Ohms, but I don't need anywhere near that power in my office. I've been listening at -12dB for most part, and it's about as loud as I would want in my office.

Bear in mind, I'm using a Mach II and Lush^2 in my office. Compared to a Mach III and Lush^3, it's probably not surprising that it's not as exciting a sound as it could be, perhaps.

Still, very, very nice to listen to though.