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DIY Pass Labs First Watt F5 amp impressions

I recently acquired a well- built DIY First Watt F5 amp for the cost of the parts, which is the understanding among those that build the designs that Nelson Pass has made available to the DIY folks.  I have been using a McCormack DNA .05 Deluxe amp and a Don Sachs 6NS7 tube amp to drive my Spatial Audio M4S Turbo S Hologram open-baffle speakers, which are ~94 db efficient.  I have raved about the McCormack amp on this forum, but swapping the F5 for the McCormack amp has been a  sheer revelation.  I have had dozens of tube and class A/B amps my system over the past 4 decades, as well as a couple of very good class D amps recently, but the tonal accuracy and 3-D representation of music with this F5 is simply stunning.  It is offers a glimpse into the inner details of the music.  I do not have the superlatives to describe the musical enjoyment of the addition  this amp provides to my system.  I am put off the heat his amp generates -- similar to that with a tube amp with a quad of KT88's, but it is a fair bargain for the most ruthlessly revealing sound reproduction I have ever heard in my system.  My regret is that I waited so long to have a Nelson Pass-designed amp in my system.  If your speakers are quite efficient, there are several variants in the First Watt line of amps that might be a great match for your system.  Mark at Reno Audio is the guy to help you sort out the best amp for your needs.
Cheers, Mark
whitestix
whitestix OP
720 posts
 
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.  
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kalali's avatar
kalali
1,977 posts
 
Love to hear all the excitement. How does the in-production F7 compare to out of production F5?
kdude66
1,200 posts
 
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.
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