Short intro: I'm 30 years of age, live in Belgium, have been audiophilically inclined since I've been 12 and have now finally succumbed to buying my first HP amp. Been lurking here for years, however. I chose the Little Dot 1+ with Valvo 6CQ6 tubes (also have Valvo CV4010 ready and several op-amps, but that can wait until I've decently assessed the qualities of the stock configuration). I have several headphones between 16 and 300 ohm but want a taste of tubes, so a hybrid like the LD1+was the logical choice.
Now onto the problem. Excitedly I plugged in my Sennheiser HD-650 and the output is only marginally louder than straight out of my iPad Mini. Gain is still set to 3.5, but jeez... I expected more power. Setting the gain to 7 will still only produce a little bit more output.
I have noticed one tube is slightly microphonic, the other one exhibits ZERO microphonics when tapped and both glow very dim and red. One tube seems a bit warmer than the other, but none are really hot after 45 minutes of use at full tilt.
Could a faulty tube in the preamp stage reduce output?