The impeccable sound of the Accession takes music from vinyl and sets it on a new higher pedestal. Previously overlooked technology has been perfected to extract much more of what’s hidden in the music on vinyl records. The resulting sound from the Accession is considerably closer to the music laid down at its recording.
Record equalisation is quite a convoluted process complicated by historical and physical technical limitations – for records to work at all required some considerable compromises simply to cut and press the groove. This is why record EQ exists and why the phono pre-amp has the job of correcting it. The cartridge output is rising at a rate of 6dB per octave, and it’s completely different to the EQ applied to the record. Treating the two quite different EQs separately, the Accession first strips away the cartridge’s contribution to the frequency response. It then deals with the record EQ.
The combined “EQ’s” make up a complex curve of different slopes pictured below. The solid black curve is the signal the phono preamp receives at its input.
If we can EQ the contribution from the cartridge and amplify it, the curve will rotate 45 degrees to the right as shown by the faint broken red curve. This is what the Accession does. It EQ’s the cartridge first of all so all that is left to do is EQ the record’s contribution, which it does in its second stage. Rotating the curve only takes a single opposing filter slope to do the job.
It just so happens that a handful of solid-state amplifying devices have an open-loop frequency response which match the required slope perfectly, making the amount of negative feedback required constant at all frequencies on the slope. This is really important because that constant negative feedback makes the input and output impedances constant too. The cartridge sees a constant load and that’s quite different to the conventional way of doing things — it makes a big difference to how it sounds.
- Adjustable and fixed level outputs
- Volume / output level control
- RIAA, NAB (American) and FFRR (British) vinyl record EQ’s
- Flat / CA (constant amplitude) alternative EQ
- Mono / stereo switch
- Four cartridge capactive loading options: 100pf; 220pf; 320pf and “out”