Pre/Power Amplifiers

The ‘Prestige’ version of the Sagita preamp not only boasts an ECC82 triode-based line stage but also features balanced XLR inputs that provide just under 2x gain (5.2dB) and a max. 12.5V output (1kHz, <1% THD) from a 100ohm source impedance. Distortion is uniformly low with frequency at 0.007-0.008% [20Hz-20kHz, 0dBV; black trace, Graph 2] but increases smoothly with level to 0.016%/2V, 0.024%/3V and 0.042% at 5V output. Noise is slightly high, however, drawing the A-wtd S/N ratio down to 76dB (re. 0dBV) but the preamp’s bandwidth is wide, delivering a 4Hz-100kHz response within mere –0.7dB limits.

The partnering Titania power amp has single-ended inputs, offers a useful +26.2dB gain and, compared to the preamplifier, has a wider 86dB A-wtd S/N ratio (re. 0dBW). The ‘raw’ response into non-reactive 8/4ohm loads is good to –0.7dB/20kHz and –7.0dB/100kHz, via both 8 and 4ohm taps, with a low bass roll-off amounting to –2.9dB/20Hz. However, the high impedance of both 8 and 4ohm output taps can create huge response errors in ‘real world’ use [see boxout]. Power, from pairs of KT88s, broadly meets Fezz Audio’s 45W spec. at 2x40W/8ohm and 2x50W/4ohm, via 8 and 4ohm taps respectively, with 2x50W achievable into 8ohm at 2% THD. Under dynamic conditions the output into 8/4ohm loads is a consistent 54W (re. 3% THD), falling back to 46W and 32W into lower 2 and 1ohm loads [see Graph 1, below]. This same graph [and purple/red traces in Graph 2] also illustrates the steady increase in THD with output, from 0.17%/1W to 0.45%/5W and 0.72%/10W up to 1.4% at the rated 45W (all re. 1kHz). High sensitivity speakers, with ‘flat’ impedance trends, will be the Titania’s preferred partners. PM