Graham Slee Accession MM Phono Stage (with PSU1)

Graham Slee Accession MM is the phono preamp for vinyl enthusiasts which uses a different kind of technology to reveal much more detail and further relegate vinyl deficits.

The Sound

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 result is impeccable sound that’s considerably closer to the music laid down at its recording.

Record Equalisation

The design recognises something most other phono preamps miss; record equalisation is quite a convoluted process complicated by technical limitations. Record EQ and phono preamps don’t generally consider the actual cartridge being used which has a rising response.

The cartridge output is rising at a rate of 6dB per octave, a 45 degree slope, and it's completely different to the EQ applied to the record. Ever since the dawn of the magnetic cartridge, phono preamps have seen the combined EQs of record and cartridge as being one.

Accession Changes It All

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 records own EQ was applied when the record was recorded, and even if you just bought the record you're playing today that event happened some time ago, whereas the phono cartridge is applying its rising response in real time now as the record is playing. These are two completely separate events in time.

Equalisation

Accession equalises and amplifies contribution from the cartridge first of all so all that is left to do is EQ the record's contribution, which is done in its second stage. This 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.

The constant negative feedback makes the input and output impedances constant too. The cartridge "sees" a constant load which makes a big difference to how it sounds. But it's not purely subjective. High frequency distortion melts away... just 0.002% THD at 10kHz on the Accession's fixed outputs.

Features/ Benefits

In a frugal or minimalist vinyl only system, the volume control drives a power amp and the fixed outputs can drive a headphone amplifier. As part of a "traditional" system the variable outputs can be used into an ADC or sound card to do "vinyl rips" while the fixed level output is connected to your preamp, integrated amp or receiver for normal listening. The different record EQ possibilities make it great for archival duties if you have old mono LPs and EPs which don't sound quite right.

Solving Digitizing Clipping

Digitising vinyl can be distorted by the wrong signal level. Too much overloads the input of the ADC resulting in a hard clipped sound. Using an "L-pad" attenuated interconnect cable can help but with quieter records you'll be recording several bits down. The Accession solves this by giving you a volume or output level control followed by a buffer stage to get the impedance low enough.

The output level control is followed up by a high quality discrete transistor buffer stage which gives you the low impedance drive your ADC expects. The fixed level output allows you to monitor what you're recording by connecting it to your main system, or to a headphone amplifier, as you record from the variable output.

Minimalist System

The volume control and buffer stage is also a solution for those only wanting to play vinyl through the bare minimum of system components. All that's required is a reasonably sensitive power amp for the Accession to drive.

Partner it with a pair of Proprius monoblocks and cartridges (outputting ≥ 4.5mV) to reach high volumes with excellent sound quality. The Accession's output buffer stage was developed specifically to prevent input saturation from ruining the clean signal from the phono preamp section. It handles the full post EQ peak to peak signal without any slew-rate limiting.

Mono Authenticity

Older mono records can sound a bit muffled or a bit too bright because they were not recorded to "modern" RIAA characteristics like stereo records Because many older users will have some of these records, LPs, EPs and even singles in their collections, Accession includes a switch to equalise them, as well as a mono switch for authenticity.

Capacitive Loading

100pf is ideal for the vast majority of MM cartridges when combined with the 50pf to 100pf of arm and cable capacitance. But as the Accession is made as a tool to extract maximum information from vinyl records, it features four capacitive load settings. The effect on sound will take the high frequency peak in the 10kHz to 20kHz region lower or higher, making the peak larger or none existent, between the maximum loading and minimum loading, respectively.

Moving Coil Cartridges

The Accession is designed for high output cartridges, but if you want to use low-output MC too, partner it with the Elevator EXP Step-Up for an unbeatable all-cartridge phono preamp combo. It is supplied with the flagship outboard PSU1 power supply, with a choice of supply voltages and power cords.