Pre/Power Amplifiers

Earlier Primare amplifiers were equipped with the brand’s own analogue Class D amplifier technology called UFPD (Ultra Fast Power Device) and its UFPD 2 is employed in the new I35. Nevertheless the UFPD circuit occupies a substantial PCB real estate and is very costly to build – two factors that militated against its use in the I15. Primare looked to an ‘off-the-shelf’ solution but its choice of Hypex’s UCD102 module was not arbitrary – while it is more affordable and certainly more compact in production design, its technical ‘fingerprint’ is closer to the UFPD, and vice-versa, than any other Class D alternative. Both are very stable, single-ended analogue Class D types that offer an entirely predictable response and distortion regardless of speaker load. And, as we’ve proved in earlier reviews, that’s not something we can say of all Class D amps [HFN Aug ’18 & HFN Jul ’16].

The inset graph shows the I15 Prisma’s consistent response into 8ohm (black), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads using a 192kHz digital input [note the 1kHz-90kHz scale]. The Class D section is analogue but as all Primare’s mid-circuit processing is digital this means the single line input is first digitised at 48kHz/24-bit. This is converted back to analogue before the Hypex amp but it does mean the line input’s response is limited to –0.6dB/20kHz. PM