“The M-stage HPA-1 was purchased by me from an eBay seller about a year ago for $180 including a class A biased OPA627 op amp. The HPA-1 was the first generation in the M-stage series and have since then been followed by the HPA-2 and the quite recently released HPA-3. The HPA-1 was released back in 2010 but I still think that it offers enough interesting features to be worthy of a review in...” --peter123
“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
“ I orginally purchased this amp on May and held off my review until August. Headgear used: Q701, er4pt i Prologue ii The search iii Purchasing iv Arrival v Initial impressions vi Usage over the months vii Final verdict Prologue: I previously owned the micca origen amp/dac unit that I purchased for $100. The amp was powerful enough to drive my Q701s on high gain...” --akg fanboy
“ Me: I am an amateur musician & avid admirer of music. I would like to call myself a music enthusiast, rather than an audiophile. I was inspired by music since childhood, and as the time passed, the passion of music grew in me, and that subsequently led me to join Head-Fi. I usually like to listen to Indian Classical Music along with Bollywood songs. My main listening genres include...” --YoYo JoKeR
“ ****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
“I needed a reasonably priced DAC/headphone amp to go with my Senn HD650s. This amp/DAC offers amazing bang for the buck. I have owned a number of good DACs and headphone amps - is it as as good as my Violectric 200/800 combo? No way. But, teamed with a pair of rounded/smooth headphones like the HD650s, it makes a great entry level combined amplification and DAC...” --gogogasgas
“DISCLAIMER I would like to thank Matrix Audio, for I have received this unit from Matrix themselves, free of charge. Please take note, however, that this would not affect the bias of my review whatsoever. INTRODUCTION The Matrix Mini-Portable is Matrix’s first step into the portable realm. And a big step, at that – the Mini-Portable is priced at $349, where there is a lot of heat in that...” --WoahReQQuiem
“After spending a lot of time with some high quality tube amplifiers, I thought it was time to revisit the world of solid state (using sound processing chips rather than tubes). Some headphones seem to pair well with tubes while others like solid state so it's always nice to have both options available. The amp I decided on is the Matrix Quattro amplifier which offers balanced and unbalanced...” --Loquah
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...