The Seven phono is the first point of entry into the world of Tron phono amplifiers and is used to increase the musical output from your cartridge and to balance the frequency response to the correct RIAA standards, then present a low impedance output to drive your preamplifier or main amplifier. The phono stage is a critical and highly sensitive part of the analogue amplification stage and I have worked over a long period of time to produce a consistently musical and tactile experience treating the delicate musical output from the cartridge with care and respect. I have kept the stages in the Seven phono to an absolute minimum, which is key to maintaining the integrity of the dynamics of such a small signal source and have selected valves/tubes (3 in total) that are both musically open and also easily obtainable so long term listening pleasure with be insured. The Seven phono can be supplied setup for either moving magnet or moving coil cartridges to suit your personal choice. The challenge to deliver truly stunning results from a low output moving coil, and maintain a low noise floor have been worth it, and the moment you place the stylus into the record groove this will become obvious.
All Seven MC phono stages can be specified with 20dB, 26dB of MC gain. A custom MC gain setting can be specified at time of ordering.
Moving Magnet gain is 49dB.
The coil options are as follows:
+20dB for cartridges with an output of 0.3mV to 0.9mV.
+26dB for cartridges with an output of 0.2mV to 0.3mV.
+30dB for cartridges with an output of 0.1mV to 0.2mV.
+40dB for cartridges with an output of less than 0.1mV.
The output stage has a very low impedance high current output, which enables it to be used with any pre-amp or main amplifier, whether valve or transistor, or even a transformer type volume control (TVC).
Inputs: 1 RCA input (L & R). Dual inputs are available on the Reference, Ultimate and GT models.
Outputs: 1 RCA Phono output (L & R)
Valve Complement: 2 × 12AX7 (low noise), 1 × 5814WA.
Frequency Response: 5Hz–37.5kHz ± 3dB. RIAA within ± 0.5dB
Gain: 48dB – MM. 68dB – MC low gain. 74dB – MC high gain
Output Impedance: <1000 Ohms
Mains Supply: 115–240 volts AC (50–60Hz). Earth lift included.
Power Consumption: Nominal 12 watts
Dimensions (mm): 450w × 103h × 335d
Weight: 7kg (net)
Warranty: 2 years (parts and labour)
Seven Reference Phono Stage
The Seven Phono stage can be upgraded to the Reference specification to further improve the musical performance from your valuable record collection. Graham painstakingly sources truly unique resistors that in such a simple circuit really bring out a richer and more intimate performance from the artist. We also upgraded the capacitors to a custom specification to work in harmony with the improved resistors; as in most development activities changing one thing in isolation hardly ever results in a balanced improvement. Graham says “it never ceases to amaze me how improving one component can impact the music in such a significant way, and also how long it takes to find the right combination to retain true harmony.”
Seven Ultimate Phono Stage
The Ultimate is the penultimate step towards analogue perfection, and involves the use of solid silver wiring throughout the critical signal path, and silver MC transformers. Silver as a conductor has the advantage of a more revealing and transparent reproduction of the music, however care needs to be taken to ensure that this is delivered in a complete and unified manner as sections of silver in a component in isolation rarely provide a benefit. Finding the right dielectric (insulation) for the cables is also critical to extract the best from this expensive material. Graham has also redesigned and built a more significant power supply that is unique to audio, which has the effect of making silences darker and dynamic shifts in the music more dramatic. The result is a little like cleaning your windows; you did not necessarily notice they were blocking any light, until afterwards.
Seven GT Phono Stage
The Seven GT is the final step towards analogue perfection, and involves the use of a completely new power supply circuit for all the critical stages. Graham says this power supply was 5 years in the making and makes a huge improvement in fidelity taking the Seven GT to one of the finest phono amplifiers ever made.
Tron Seven GT Review – Hi-Fi News March 2013
Confessions of a part-time Audiophile – April 2012
6moons Review – November 2011
6moons Review – November 2006