The Challenge Amp 1 is a high performance headphone amplifier, carefully engineered for precision and transparency. This powerful and versatile amp will drive virtually all headphones with 'reference grade' fidelity.
It features excellent specifications all round, including vanishingly low noise and distortion, ruler flat frequency response and near 0-ohm output impedance, all vital for a ensuring reference sound quality. The low gain mode and silent background is great for sensitive IEMs, while the high output power will easily drive more demanding headphones such as orthodynamics.
The amp is designed and made in England of predominantly British sourced parts. The wooden enclosures are hand made in Tisbury, Wiltshire from American black walnut and lined with copper shielding, while the 3mm aluminium chassis is brushed, anodised and CNC machined for a solid, high quality finish. The circuit board and most other components come from British suppliers and are assembled and tested in house by us, ensuring every amplifier meets our meticulous standards.
Features
Innerfidelity
"The Challenge Amp 1 definitely challenged my beliefs about what an amp of its type and cost could do. Highly deserving of being included in InnerFidelity's "Stuff We Like"."Pro Audio Web Blog
"4.5/5 - Tisbury Audio are onto a winner with their CA-1."Hifi Pig
"The looks and sound combine to an almost perfect headphone amp for the price."Headfonics
"If you are after a smooth effortless vocal centric performance with good low end extension... the CA-1 could be that right kind of classy addition to your system."Old & New Sound
"Clarity and definition is the hallmark of this amp without a doubt... The tone is fantastic and allows the headphones to really be themselves without any influence."Auriculares-HIFI.com
"With the CA-1, headphones reach a level that I did not think they could get. I finished with the hair on my arms standing up."Distortion | Percent | Level | Notes |
THD 100 Hz | 0.0004% | +6 dBu, 32Ω | See (1) |
THD 1 kHz | 0.0003% | +6 dBu, 32Ω | See (1) |
THD 20 kHz | 0.003% | +6 dBu, 32Ω | See (1) |
IMD CCIF | 0.0004% | +6 dBu, 32Ω | See (2) |
Maximum Output | Volts (RMS) | Power | Notes |
16 ohms | 3.4 V | 725 mW | See (3) |
32 ohms | 5.5 V | 945 mW | See (3) |
50 ohms | 7.1 V | 1010 mW | See (3) |
100 ohms | 8.1 V | 655 mW | See (3) |
300 ohms | 8.2 V | 225 mW | See (3) |
600 ohms | 8.3 V | 115 mW | See (3) |
Gain: Low / High | 6 dB (2x) | 16 dB (6.3x) | |
Noise Floor: Low Gain | -110 dBV | 3.2 μV RMS | See (4) |
Noise Floor: High Gain | -107 dBV | 4.5 μV RMS | See (4) |
Dynamic Range | > 128 dB | See (4) | |
Output Impedance | < 0.2 ohms | ||
Input Impedance | 10 kohms | ||
Freq. Response: 20 Hz - 20 kHz | -0.04 dB | ||
Ch. Balance: full vol. / -45 dB | < 0.1 dB | < 1 dB typ. | |
Crosstalk: 600 Ω / 32 Ω | -97 dB | -80 dB | 1 kHz, 0 dBV |
Dimensions | 204 x 170 x 74mm | 8.0 x 6.7 x 2.9" | |
Weight | 0.9 kg | 2.0 lb | Not inc. PSU |
Power Supply | 12 V AC | ≥ 1000 mA | |
Max Power Consumption | 12 W |
All tests BW = 20 Hz - 22 kHz, except THD 20 kHz BW = 20 Hz to 96 kHz.
(1) THD: 10 pass average, high gain setting, 1 V RMS input.
(2) IMD: 19 kHz / 20 kHz 1:1, no averaging, high gain setting, 1 V RMS input.
(3) Max continuous output, both channels driven, 1 kHz sine, ≤ 1% THD.
(4) Noise: A-weighted, no averaging. Dynamic range: ref. 8.3 V RMS.
Specifications subject to change without notice.
High Performance Amplifier The CA-1's circuit is the result of 18 months of development, exhaustive testing and listening trials. It uses a combination of ultra high performance LME49600 output buffers, precision spec. surface mount parts and a compact 'high speed' board layout. Great care has been given to minimise every possible source of audible degredation; noise, distortion, output impedance, frequency response, phase shift and crosstalk are all excellent. It's also efficient, runs cool to the touch and is stable into any load, so you can connect any length cable. |
Gain Switching Low and high gain modes are set to 6 dB (2x) and 16 dB (6.3x) gain. The gain switch controls a high quality relay located directly inside the amplifier's gain stage. This ensures the sensitive areas of the circuit are uncompromised and no performance is lost in either setting. |
Power Supply The mains transformer provides clean AC to the 7,200 µF capacitor bank, which feeds a low noise, low impedance regulated power supply.We use an off board mains transformer, which is advantageous in a number of ways: • Isolates audio circuitry from electrical noise, no mechanical hum |
Muting Relay A muting circuit with turn on delay and fast acting AC detection protects your headphones from any harmful transients during power on/off. If the AC supply is switched off or interrupted, your headphones are disconnected instantly.The front LED displays the status of the protection circuitry: Blue = normal operation. Green = muting circuit active. |
Three Year Warranty
The Challenge Amp 1 is covered by a three year limited warranty on parts and labour. If you get any problems with your item in this time, we'll repair or replace it at no charge, subject to terms.