DIY Pass Labs First Watt F5 amp impressions

Yep! And then doing everything he can to get guys like me to build them!
More people should give it a try. It's like they say: the best amp you'll ever hear is the one you built! 
There's a lot of upsides to it though. You can't buy amps like that, period. Dealers don't even want to sell you amps that idle at 135F. 

Gents,
I just returned from hearing a $6K Bryston 4B3 amp in a pal's system and got home to my system with the F5 warmed up and am hearing artifacts to the same music I was just listening to in my pal's system that were absent in his system.  The Bryston sounded excellent, but it didn't provide the inner glimpse of music that the F5 does.  However, I am biased so take that into account.  

I kinda think I got the sweet spot of the First Watt amps with my F5, but clearly their are nuances to all of them, particularly the more robust version of the F5 that our friend has built. At retail prices, the First Watt amps are reasonably priced, but if you are a DIY sort of guy, they would be an affordable way to have some of the best amplification available, so long as they are compatible with the sensitivity of your speakers.  

Seeing as how Nelson only constructed 100 examples of the F5 9-10 years ago they're probably as rare as hens teeth these days. The F7 is supposed to be an improved revision of the F5. Never heard one though. If one is of the DIY mindset and has a serious thirst for more power than a standard F5, there's always the F5 Turbo. The F5T can be scaled up to 200 watt mono-blocks and run on balanced input. Of course you'd need an absolutely massive cooling solution for an amp like that, but it's totally possible with this topology. 
The reason I was able to push mine well beyond 25wpc is because the chassis I used has bigger heatsinks. It's actually a pretty simple amp to build which is part of the reason I chose it as a first build. Under $1000 for an amp like THIS? I feel like I just robbed a bank, and not only got away with it, but found they dumped a million dollars in unmarked bills in my bag! You can't just go buy amps like this. Every single F5 in the world is hand built with quality parts and carefully tuned in a "time is no object" way. If you ask me, that is what true high end is. Sure sounds like it from my chair! More people should try building one. 
Whitestix, I completely agree with your assessment of the F5 sound. It presents with a level of purity, accuracy, power, dimensionality, and ruthless neutrality that just staggers and leaves one groping for hopelessly inadequate adjectives to fully sum up the character of the amp. It's one thing to read the reviews and opinions of the amp, but to actually hear what it does is just impressive. Can it really be THAT good? Yeah. It's THAT good. 
The extra power is nice on my build, and it probably lowers the distortion a little, but I seriously doubt I'm using all of what it can do. 75 watts of peak class A power with 92dB sensitive speakers? I'm probably just scratching the surface. 

Love to hear all the excitement. How does the in-production F7 compare to out of production F5?

kalali,

The F7 is slightly more forgiving and smoother sound than any of the variations of the F5 that I have heard.

The F7 has the lowest parts count of any of the first watt amps.
Comparing the F7 directly to my Diy sit2,I much prefer the Sit2 for it's liquidity,texture,warmth,midrange body meat on the bones and even more overall smoothness than any of the first watts,and I've heard them all except the F1 and Sit1 Mono's.
The sit2 gets the closest in overall sonics that a good tube amp brings to the sonic table.IMO.

Now comparing my Sit2 to my LTA Zotl40,both driven with the MZ2S.I'ts going to take me a couple days of proper evaluation to sort this out.

All of the first watt amps need to be paired in a quality system,the better you feed them the better they perform.

Kenny.