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This little preamp adds a nice touch to my Peachtree Nova 300. It smooths out the "brightness" often seen in these class D powered integrated amps. Immediately I could hear things in my music I hadn't heard before. Little details undetected powering my very efficient Zu speakers. I'm assuming as tube ages the sound will mellow even more? The assembly went well, although the case build with the tiny nuts made the task difficult. Also the pictures of the resistors were different than those I received, so I needed to call upon my color codes to make sure I had the right parts before testing with multimeter. Now the mystery. I powered up amp and took readings at advised test points. All were well in tolerance except for T7 an T8 which should be around 9.5 VDC. My test points read 5.01 and 4.91 VDC. The blue glow on the tube shined brightly on each channel. Hmmm. I rechecked everything, but nothing was awry. I could not adjust pots to compensate to 9.5 VDC. So, I proceeded to hook up the amp and see what if any sound was present. To my surprise, music filled the room and sounded as I had expected. I didn't find anything in the forum of anyone experiencing similar results. The classic case of leaving well enough alone carries on........

Waited a year till this unit was back in stock. Finished about a month ago. Very easy to build, IMO. Excellent sound to my amateur ear. Paired it with my ACA Amp & RME DAC to a very dull set of speakers as a test. It was the best sound every gotten out of those speakers. No tweaking done on the RME DAC to improve the sound. Now paired with Zu Audio Dirty Weekend Mk2, excellent pairing. Have only heard the KORG tube ring one time when I dropped a wrench on the preamp, very extreme treatment to make it ring. Highly recommend if your looking to make something and learn a bit about circuits. It is a unique product so I don't think you can look at this in a buy verses build comparison.

I ordered this kit for several reasons, to keep myself current in building, as an adventure in low power and to see if the magic of Class-A was still there for me. I owned a Sumo Nine many moons ago and loved it.. I took my time with this kit and triple checked everything and spent a lot of time on getting it 'pretty' - especially the wiring. It powered up perfect first time and other than the adventure of chasing the bias point it worked perfectly. The bias adjustment pots could be 10 turn type, it would be easier. When you make a bias adjustment it swings up and down in a decreasing amplitude sine until it stabilizes - make very small adjustments and wait ! This amp has no right to sound this good. It is powerful ( 8w ?? ), dynamic, transparent and smooth. I cannot believe the big electrolytic in series with the output allows the highs to sound this good. 8 watts drives my Epos M5s ( medium efficiency speaker ) to wife yelling levels in a medium sized room. As noted by others you will have to feed a decent level input to the amp to get full volume but my Creek CD player had plenty through a home made 10k pot-in-a-box 'preamp'. This amp absolutely kills many much more expensive amps at lower volumes. It is now my reference. If you're wavering on getting a kit - JUST GET IT !
You won't be sorry. Thanks Nelson !!!!

I learned a lot while making this, and now I have a great amp to power my desktop speakers. I’d love to make another one for monoblocks!

The quality of the parts and the description is very good, the hearing tests started ........

Perfect

I ended up building three of the kits, one as a stereo version, using RCA's with unity gain, so it could be used inline from a preamp to an amplifier. The other two kits, I built a Balanced version, one kit for each channel, once again with unity gain so it could be used inline from my Balance BA2018 preamp to my ALEPH J amplifier. All of these projects were built using parts and enclosures from the DIY audiostore.

Get some of this and make you diy easier.

I had been thinking about buying or building a tube amp. Then I discovered the Nutube. This was a fun diy build project resulting in a great sounding pre-amp. I plugged this into my ACA and noticed a new dimension to the music.
When I started this project, the completion kit was not available so I ended up sourcing those components. Another learning experience.

As a longtime audio hobbyist this particular product is new to me, having used numerous solder types previously including another popular brand eutectic. So far I’m finding FIRE-METALL is terrific for wiring passive crossovers, as well as for terminating speaker cables and interconnects. It has excellent joint strength and looks great too in case the finished work will be exposed. I expect to see the same desirable results with PCBs though I rarely dabble with them.
When experimenting with eutectic solder for the first time it can be tricky to command, but once the correct temp is dialed in your project(s) will thank you and your patience will be rewarded.
(With their rebuild still in progress, the first-order crossovers depicted belong to a pair of ‘70’s era Rectilinear XI’s… a ported 10” 2-way bookshelf design employing the ever popular 2” paper cone tweeter with phenolic-ring surround. Only the sand-cast resistor being kept for posterity, all else upgraded. FIRE-METALL used throughout to optimize performance and longevity.)

The amp sounds awesome! Just take your time, follow the directions, and you can’t go wrong. I had a slight hum on the initial build with no sound but went over all my soldering and found the issue and has been working ever since. I even had mine specially powder coat painted in a color of my choosing which makes the amp even sexier! It’s a great SET amp for the price with all high quality parts. A definite end game headphone amp.

It came nicely packed and I actually bought this FET Kits separately and bought the other parts to complete the whole Aleph J Amp. The sound signature of this design, thanks to the very generous Mr. Pass is so unique with holographic and engaging sound stage, well controlled lows and very sweet mids and highs.

This is my reference DIY amp now after building the ACA and the F4. Its is just a cut above all the ones I built. So worth the time and money and I am delighted I decided to build it.

Just had the V5i installed inside the DAC and the improvement manly in stage and sensing more details is obvious

A great device works great and handy having all components in kit

I've just built B1 around those. Haven't auditioned it yet, but the oscilloscope says it's basically perfect 10Hz-500kHz. I'm very happy so far, I'll probably come back for more.
Cheers!