Amp1 Balanced:

Alone, Amp1 is a compact inexpensive desktop headphone amplifier that sounds incredible for the money.  As a PAIR, Amp1 gives you true balanced sound in a compact package with exceptional sound quality.  The key to making this work is connecting a balanced source (cd/sacd/dac/other) to both amps.  Using an XLR to 3.5mm cable (or XLR to 1/4“ then 1/4“ to 3.5mm adapter) connect the left output of the source to the input of one Amp1, connect the right output to the input of a second Amp1.  So instead of  L/R/Gnd on the input the first Amp has Left Positive signal/Left Negative signal/Gnd, the second Amp gets the Right Positive signal/Right Negative signal/Gnd.  Since each amp only handles one channel, the outputs have to be tied together to power a set of headphones.  Shown below is a dual 3.5mm to 4 pin XLR adapter that allows you to plug in all of your 4 Pin XLR balanced headphones.


“Used as a pure headphone station for late-night listening and connected to the Luxman D-06 via the Mogami stereo-to-mini cable, the results went beyond all expectations. The transparency of the Amp1 helped me to appreciate the enormous potential of the Luxman player. Compared to the headphone output of the Luxman L-590 AII integrated amplifier however, I preferred the RW Audio for its greater transparency and accuracy.”
Joel Chevassus, 6moons.com

Design:

– Amp1 was designed mainly using AKG K601’s (120ohm) for listening tests, because of this it has a wonderful synergy with AKG even more so the K601/K701/K702 (120/62ohm) Family.
– Further testing was done with Alessandro MS1’s (32ohm), Grado HF-2’s (32ohm), Sennheiser HD650’s (300ohm), PX100’s (32ohm) along with vintage AKG K240 Sextetts (600ohm) and Monitors (600ohm).
– Amp1+HF-2 is a hit or miss combination, sounding better than almost all other headphones on some tracks while leaving you reaching for the skip button on others.
– Has a nice synergy with all other headphones I’ve tried, and from customers using a wide variety of brands and models, some very high efficiency headphones may experience a slight hiss due to the gain required to drive higher impedance/low efficiency headphones. Battery1 is an inexpensive solution that virtually eliminates all noise even when used with the most efficient IEMs.
– Works equally well driving 32ohm through 600ohm headphones and even IEMs when Amp1 is paired with Battery1.
– Designed to integrate into your home or office computer station using a line in from your pc and providing a preamp output to your powered computer speakers, simply plug in your headphones and without swapping cables the speakers are muted and your headphones provide a wonderful listening experience.
– Makes an excellent and affordable upgrade to all internal and external PC/Mac sound cards and usb dacs.
– Works very well with all ipods and mp3 players, for best results use the line output instead of headphone output if available

Features:

– NEW The Amp1 upgrade! Click here for details.
– +/- 12v power supply is compatible with many high end op-amps, Amp1 comes stock with a pair of LME49860 (8 DIP) op-amps, one for the left and right respectively
– Compact desktop design
– Solid aluminum volume knob, in both smooth and knurled finish (both included)
– High and low gain switch to work with most headphones
– 3.5mm input, headphone output, and pre-amp output jacks
– Input capacitor bypass for increased sound quality when not required
– Alps volume pot with integrated on/off switch
– 3 channel active ground architecture
– 24v regulated power supply, can be replaced with a high quality regulated supply or battery pack between 16-24v dc
– High Performance, High Fidelity National Semiconductor op-amps for the left/right channels, (LME49860 Stock), (LME49720HA Upgrade)
– High current National Semiconductor op-amp for isolated headphone ground (LM6171)
– All op-amps are socketed and can be easily replaced or “rolled” by the end user (Tools included to open Amp1)
– Choice of Silver or Black anodized enclosure

Specifications:

Test Amp1 Headphone output
Frequency response (from 20 Hz to 20 kHz), dB: +0.01, -0.05
Noise level, dB (A): -105.5
Dynamic range, dB (A): 96.5
THD, %: 0.0021
IMD + Noise, %: 0.0039
Stereo crosstalk, dB: -96.8
Amp1 Desktop headphone amplifier
$139.00