Nobsound 12AX7 (ECC83) 12AU7 (ECC82) Vacuum Tube Preamp HiFi Preamplifier

I have always loved tubes but for many years could not afford a tube pre-amp. Although I can now, the idea of a simple and inexpensive point-to-point wired pre-amp was very appealing, so I bought one.First, it’s a really nice looking piece of “kit” as the British would say. No labels on the controls, but there is only one switch and two knobs, so they seem unnecessary anyway. A good size transformer (for a pre) is nice.So, the sound. I wish they sold these without tubes because the ones it comes with are awful. After listening and not liking what I heard, I got my box of old tubes and replaced just 2 of the 6 with just moderately priced Russian tubes (not even NOS) as this was what I had on hand. Holy cow! Everything improved and the soundstage opened up dramatically and I am listening to this out of choice and not necessity.I suspect many will use this with solid state equipment to add some “tubyness” to the sound and I suppose it may work for that, but I’m using it with tube amps and it it glorious!Note: Every time I put a transistor in the signal path I regret it, so all tube is now possible at a lower price than anytime in history, and I would encourage any audiophile or budding audiophile to take advantage of the moment and put together a tube pre and amp and enjoy the music!

Buyer’s beware, this is a 110VAC unit! No users manual, no specs sheet that comes with the package, not even a tagging on the unit, they gave you a one pager layout of tubes in Chinese! The socket for the rectifiers doesn't fit! they sold this product internationally without specifying the voltage rating so when I plugged it everything goes up to smoke….literally

So, I received this 9/14/2020, in a well packaged box. WIMA and Nichicon caps. JJ 12AU7 tubes, but lower quality 6Z4 rectifier tubes along with the 12AX7 tubes. Point-to point soldering very good. Input selector has illogical wiring for the 4 inputs. Connectors on the back are numbered 4-3-2-1 left to right, but selector is 1-2-3-4 left to right. Crazy. I replaced the the rectifier tubes with some good Russian tubes, and the 12AX7s with NOS 1966 Mullards. The sound is amazing. Now, why is this going to be returned? The left 6Z4 socket is extremely loose and the tube flops back and forth a good 3/8 To 1/2 inch. The right is loose also, but acceptable. This should have easily been caught with a good quality control check, unfortunately it did not. These sockets seem to be available from China only, so I’ll return this one and reorder another.

Excellent value for the money. You must to replace the tubes for better ones (apparently the stock rectifiers are OK, though). I have only played the unit with the replacement tubes (I chose two JJ 5751 in lieu of the 12AX7, and two Mullard 12AU7 reissue). It may come down to the tubes or to the unit, but there was initially, at times, a slight shrillness to the trebles which was an issue, but I gave the unit the time to burn in, and the sound settled entirely. It is now very smooth and nice with jazz, small ensembles, classical and voices. The unit must be above a 100 hours right now, and the treble has been smooth for a while. I believe that the bass could be a little bit more present, however this is most likely owing to my choice of tubes. In any event, I recommend that you give this unit a solid chunk of time to burn in before judgment. I purchased this particular preamp because I needed additional RCAs to switch between sources, without the need for a phono section, and I wanted to add a little tube sweetness to my digital amp: my favorite little Kinter 2020a+, a tripath unit I love. The pairing with the Nobsound works very well with my large advents. Highly recommended indeed.

A great value for a 100% tube preamp (No transistors here). On stock 12au7 tubes the sound is airy with a lot more detail in the mids and highs compared to my solid state preamp. But with the stock 12au7 tubes the highs can be a bit metallic sounding.So, I replaced the 12au7 tubes with a pair of 5814a tubes. Now, the highs are creamier and sweet. The lows are a lot more powerful. Overall the sound became more pleasing and warm.Another issue is the preamp's lack of grounding. I had to open it up and connect the ac outlet ground to chassis to properly ground the preamp. Hopefully Nobsound can fix this issue in the future because this is a very good sounding preamp.