Angstrom Research

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PREAMPLIFIERS

.:REFERENCE ONE

.:REFERENCE 2

.:REFERENCE SE

>>PHONO ONE

.:PHONO TWO

Phono preamplifier
"PHONO ONE"

The Angstrom product range also comprises its jewel, PHONO ONE, which enables raising to the nth power of the unquestionable and unsurpassed gifts of musicality and listening of analogue discs.
It is an MM and MC phono stage with a single frame to favour increased needs for space, but with a separate, screened power section inside. The circuiting is totally valvular, both in the signal stage and the power stage.
Like all ANGSTROM RESEARCH products, PHONO ONE is totally handmade with suspended cabling.

- The power supply has a rectifier comprising an SRPP followed by a P-GRECO filter. The voltage regulator is of the DC pump type, using a gas diode (vapour mercury or neon) and a 6BM8/ECL 82 triode/pentode, which also acts as a stabiliser, followed by a 6V6 GT tube, which supplies the power to the audio valves.
The filaments of the power supply valves and the audio valves are regulated and stabilised directly to avoid unpleasant noise. The power supplies are completely separate with dedicated transformers for the filaments of the audio valves, the filaments of the power supply valves and for high voltage (anodic).

- The audio circuit is made in such a way that the signal, in the input stage, adopts a cascade movement, first crossing a parallel 6DJ8/ECC88 valve (dual triode), then a 12AX7 / ECC 83 followed by a 12AT7 / ECC 81 valve connected in TOTEM-POLE (SRPP).
The final stage is made up of a 6J5 or 6SN7 single triode connected to a cathode follower, with the sole function of lowering the output impedance to about 300 Ohm (BUFFER).
The circuit has no countercoupling and the RIAA is totally passive.
The components are selected by hand, with very low ESR electrolytic condensers, MIL standard metal resistances on the audio signal and transformers and filter inducers built to our specifications. The cabling is created using MIL-W-16878 (awg 24) standard cables of the very highest quality.

Very rare vales like the 6J5 GT made by FIVRE (made in 1956) L63 OSRAM/BVA (1951), M3624 (6DJ8) TOSHIBA (1960) h 12AXT CIFTE' (see photos of valves) are available for the most demanding customer.
With PHONO ONE the reproduction of old vinyl takes place without background noise, benefiting the vividness and resolution of the micro-detail.
Extraordinary depth and amplitude of image, with affirm, powerful bass. A preamplifier dedicated to vinyl enthusiasts capable of arousing emotions in those listening.

VALVES IN THE POWER SUPPLY

2- 6AX4/6AW4 GT HALF WAVE DIODE
1- 6FQ7 / 6CG7 error's corrector
2- 6V6 GT voltage regulator
2- 6BM8 / ECL82 screen control 6V6 GT and stabilizer
2- OB2 WA GAS DIODE screen control ECL 82 pentode
2- 85A2 GAS DIODE

VALVES IN THE AUDIO CIRCUIT

2- 6DJ8 / ECC88 MC INPUT- AUDIO GRADE SELECT
2- 12AX7 / ECC83-AUDIO GRADE SELECT
2- 12AT7 / ECC 81-AUDIO GRADE SELECT
2- 6J5 / 6SNT BUFFER OUTPUT -AUDIO GRADE SELECT

TECHNICAL FEATURES

Phono MC gain = 64 db
Load = 100 Ohm selected
Frequency response 15 Hz to 28 KhZ .25 db of RIAA
Output moving coil cartridge 0.15 mV ( 150 microvolt)
Output load 300 Ohm
Noise with 0.15 uV equivalent input = 76 db below 0.6 mV input
Distorsion = 1%
Dimensions in mm: 484L 404P 155L
Weight: 25Kg

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