I purchased this a little over a year ago and have tried a wide variety of tubes with it. Eventually settled on a matched pair of Voskhod Rockets from 1972. With the right tubes this little beast creates a warm sound but with great detail, punchy bass, and the sound stage is vast - just spectacular! Highly recommend.

At first it didn't work. I had to send it back. But...the issue wasn't the Fosi. It was me. I crossed my i-s and dotted my t-s w/trouble shooting but still couldn't get it to work. After meticulously going through my set up with Fosi support, I found the problem. For anyone using the Apollo Twin, here is the issue. I bought some great RCA-XLR cables to go from the Fosi to the Apollo Twin. For some reason, still a bit unclear to me, I had to switch from RCA-1/4 cables. Worked perferctly after that. I love it...I've been a dj for almost 40 yrs. My ears love the "warmth" it provides. For the record, I did upgrade to higher quality tubes. I've been digitizing a lot of my ol' house music records. Thumbs up!

It does the job for a cheap pre-amp. Pretty good for what you pay but there are obviously better upgrades.

Sounds very nice and looks cool. Ok, I bought it for the look. :)

This tube pre-amp is wonderful! Bought it and went straight with the GE5654's from Riverstone Audio. On my latest record player, I was using a simple $40 dollar Audio Technica cartridge for years and that was just fine for me. Last year I was getting into those Blue Note Tone Poet albums, I noticed on a couple that there were some spots that sounded like they were overdriving my system somehow. I read that it could be my cartridge. How was I to know what cartridge WOULD work, but then a light bulb came on and I thought maybe I could take the cartridge out of an old player from my attic and see if it works better. I happened to have a Technics 310mc in my one player that I bought at the thrift store for $8.00 15 years ago. I tried it out in my current player and was amazed at the quality of sound that this had, it changed everything for me, I didn't know records sounded that good, and no overdriven sound happening on any of my albums. The only issue is that the cartridge was not as loud. I was still able to get the volume at a decent level at around 3.5-4, but I was also getting some amplification noise, and anything past 4 simply increased the amplification noise and did not increase the music volume. So for almost a year I was listening to my records at lower volumes, with some the volume worked okay, but with others it was just too low. I thought I'd check out some preamps and I came across this one. I was only considering a tube preamp, as I was well aware of the benefits of tubes from my experience with guitar amps and my hi-fi 78rpm tube record player. Some people did say (including the MFR) that this wouldn't work with an MC cartridge. Well, if you are wise, then you would know that when people on the internet say something won't work, 75% of the time or more they either have never tried it themselves, tried it but didn't know what they were doing, or simply don't know what they are talking about. Even though the mfr and others said it wouldn't work with an MC cartridge, I knew the chances were very high that it WAS going to work, especially since my cartridge has pretty high output for an MC. Dude! My volume used to be not quite loud enough at 3.5-4, now with the Fosi Audio Tube Preamp it is totally jammin' at 1.25. Finally, I was totally jamming out again and now my system is louder and sounds more amazing than it did with just my MM cartridge I used to use. All I did the first day that I got this preamp is play record after record and shake the house and dance around and shout for joy. The tube warmth and tube gain sound is totally there! If I were you, I wouldn't be afraid to try this on a lower output MC cartridge (considering that MC specific preamps generally cost a lot more money.) I am absolutely thrilled with this preamp in combination with my Technics 310MC cartridge! It has brought new life into my home record listening experience. After dinner that evening I simply had to hear the beautiful warm sound of June Christy on my new set-up. It brought tears to my eyes. Peace!