Review on Nobsound 12AX7 12AU7 Vacuum Tube Preamp HiFi Preamplifier - Unleash Audiophile Excellence! by Charlotte Manning

Bought a bit by accident. I know the circuit and it looked well put together (see photo and schematic in Q&A). Worst case I could use the case and connectors for a DIY project (buying everything individually wouldn't be far from what I paid for it). I received it well packaged in a double box with a mouse and in the promised time. All lamps were individually boxed (as they should be) and fit in easily. Doesn't sound good at first, but after a few (2-3) hours the sound opens up and sounds decent. The weak point is the pipes, which appeared to be the cheapest the builder could find. I replaced them with premium Shuguang tubes (selected and branded by Prima Luna) and the sound is very good. I also tested some Gold Lion bulbs which I had decently blown and they were just as good. Rectifier lamps are good, but signal lamps (12AX7 and 12AU7) should be replaced with better ones. When you do this, you get quality sound for little money. This little preamp beats my completely rebuilt 1982 Luxman C-01 preamp (class A transistor) in every sound quality, even with crappy standard tubes just as well. I haven't changed the singal caps (yet), they seem to be good quality WIMA and Uxshell MKP and I don't feel the need yet. But if I ever want it will be easy as the interior layout is very well done and clear and there is space to work. The whole unit is pretty solid construction in a big aluminum and faux wood body I think, but it looks good enough for me. But you probably won't buy it for the looks as it's very simple and rough. In short, swap out your signal tubes for better ones and you've got a small but great sounding basic tube preamp for free. I can't say how long it will last as I only play about 7 hours. But if it breaks you still have a nice (non-brand) case with connectors to put in a homemade version. Equipment used to listen to this pre: Technics SL1500 MKI turntable with AT-VM95E/H cell and stylus, Cambridge. CP-2 phono stage, Prima Luna Prologue 4 power amplifier with stock tubes, homebuilt speakers (Mark Audio Alpair 10M Gen 3 head and Scanspeak 26W-8534G00 woofer in ported floor stand).