“ This is a review of the Crack amp driving Sennheiser HD800s. I haven't had the chance desire to audition it with any other cans. The price is for the amp ($213) and the Speedball upgrade ($110). I've had the combo for about two years, and have several hundred hours on it. The Crack is an OTL headphone amp kit, designed for high-impedance phones. Assembly is easy, the...” --Bill Way
“This review is based on matching the Mini X with Hifiman He-500 Headphones. You may be reading this review, unsure what to make of this Amp, asking how can a cheap sub $200 amp offer the power needed for an expensive Headphone such as the Hifiman He-500? If you have done your homework you will find this is the stereo amp everybody is...” --fluidz
“The Bottlehead S.E.X. is the mid-level DIY tube headphone amp from Bottlehead USA. As per the very well-known Crack OTL amplifier, it's a kit that you build yourself, but it's a little more challenging than the Crack due to the extra components involved. In short, the Crack and S.E.X. both have their own strengths, but the S.E.X. is a definite step up in overall sound (which is a...” --Loquah
“I have created a thread to discuss and compare the Bottlehead range of headphone amplifiers so I'll share a small excerpt here just abouthow the amp sounds, but I'd recommend heading over to the thread for much more information and opportunities to read other people's opinions and discuss your thoughts:...” --Loquah
“ ****Note**** As always, these are strictly my opinions. I try to present these products as honestly as possible and try to describe them as best as possible. As always, YMMV. ****NOTE**** FISCHER AUDIO MYSTIFY PORTABLE HEADPHONE AMP SPEC’S: Frequency “flatness”: +/- 0.5db Dynamic Range: 110 db Total Harmonic Distortion: 0.001% Intermodulation...” --LFF
UPA-200 represents a true breakthrough in audiophile-quality amplification. At last, a truly affordable stereo power amplifier that can satisfy the most discerning aficionado, and at the same, is affordable to anyone with a desire for real quality. Our advanced engineering and design techniques have resulted in an amazing new amplifier. Its rock solid performance and affordable price point...
Frequency range: 10Hz-20kHz Amplitude-frequency responce (AFR) irregularity within the frequency range: 0.3 dB Dynamic range: 110 dB Harmonic distortions: 0.002 % Intermodulation distortion (CCIF) 0.006 % Interpenetration of channels at frequency 1 kHz: -73dB Rated input voltage: 0.5 Maximalinput voltage: 3.5 V Maximal output voltage at the non loaded output: 10 V Maximal undistorted power...