Forming part of our Ultra Sigma combo, a total start again process allowing freedom to over engineer. Reinventing the amplifier utilising years of experience, taking things into the future in terms of energy efficiency, whilst giving a classic British ethos. A perfect partner with our U4PRE pre-amplifier.
| Audio Channels (quantity) | 2 | 2 RCA (Single Ended) |
| Audio Inputs | 4 | 2 XLR (Balanced) |
| NOTE: Both input types are always active; thus 2 sources can be summed if desired | ||
| Input Impedance | 10k | RCA and XLR |
| Input RFI Filtering Capacitance | 550pF | RCA and XLR |
| Audio Outputs | 4 pairs | Binding Post |
| NOTE: Double channel connectors allow separate Tweeter and Woofer cables if desired | ||
| Output Impedance | 25mR | |
| Maximum Voltage | 70V | |
| Maximum Current | 30A | (pulsed testing) |
| Voltage Gain | 26dB (standard factory setting) | 29dB |
| Current Gain | 50,000 | 94dB |
| Sensitivity | 2.2 Volts | |
| Dynamic Range | 115dB | Un-Weighted 22-22kHz |
| Inter-stage Coupling | DC Coupled | |
| Frequency Response | 5 to 20kHz | +-0.3dB |
| Distortion | 0.003% at 5W | +-0.3dB |
| Rise/Fall Time | 10uS | |
| Stability | Unconditional | |
| RMS Power into 4R | 500W | 600W at high gain setting |
| RMS Power into 6R | 333W | 400W at high gain setting |
| RMS Power into 8R | 250W | 300W at high gain setting |
| RMS Power into 12R | 166W | 200W at high gain setting |
| NOTE: Amplifier is stable into 2 ohm loads but with no increased power.** | ||
| Power Supply Connector | 10A Furutech C13 IEC | |
| Fuse | 10A | |
| Nominal Power Supply Voltage | 230Vac (50Hz) | or 120Vac (60Hz) |
| Power Voltage Selector | Internal | |
| Power Isolation Switch | On Rear Panel | |
| Standby Switch | On Front Panel | |
| Remote Standby | Connector on Rear Panel | |
| Power Consumption operational | 200W average | 1,000W max |
| Power Consumption Idle | 15W | |
| Power Consumption Standby | 1W | |
| Current Consumption | 230v – 1A nominal (5A max) | 120v – 2A nominal (10A max) |
| Power Indicator | Green for Out of Standby | |
| Fault Indicator | Red Led illuminates if clipping or protection is active | |
| Product size / weight (packed) | 590(L) x 405(W) x 152(H)mm | 14.65kg (GROSS) |
| Product size / weight (unpacked) | 382(L) x 325(W) x 97(H)mm | 13.05kg (NET) |
Operator Manual
Specification Sheet
Quick Start Guide
“How does the U4PRE stack up to a well-thought-out valve preamplifier…? Exceedingly well and is, in fact, preferable in comparison. This is by far the best solid-state internal preamplifier I’ve heard yet. Putting both the U4PRE and U500DC together, you get the very essence of a phenomenally explosive and powerful sounding combo of sonic magnitude.”
“Both Ultra Sigma models have clearly been developed over time in a considered way, meaning what you get is a well thought out and finely executed package. Given the quality of these products, I expect we’ll be seeing and hearing a lot more from Ultrafide Audio in the future.”
“We can see the Ultrafide U4PRE and U500DC amplifiers winning many fans for build, design and sound quality. This combination could be the one that puts Devon firmly on the map for hi-fi and music lovers.”
