Review on Nobsound Headphone Amplifier Earphone Pre Amp by Brandi Stone

I am using this amp with a GE JAN 5670 tube. I find it goes well with my Beyer DT990 Edition 600 ohm. The GE tube warms the sound only slightly, and that's enough to take the edge off the DT990's high frequencies. Also a good combination with Senn HD6XX. It's like almost unlimited power as it drives both at 9-10 on the volume knob. I plan on replacing the op amps in the future when I can get some Burson tubes. I tried some other tubes and really liked the Raytheon JRP 5670WA ring getters although they were too bright in combination with the dt990. Instead, I plug them into a Loxjie P20 and use them with the HD6XX in a fully balanced configuration. Overall, I'm happy with the $60 spent (plus tubes). It packs a lot of power, sounds good, and lets you tinker with the tube and op amp. It's unlikely to be your end-game amp, but it's a fun little amp that's well worth the money.