Tuesday, March 29, 2016

Monday, March 28, 2016

Alum Rock Technology 304 TL stereo amplifier


The 304TL stereo amplifier shown on this site is optimized for use with 8 to 16 ohm high-efficiency speakers and has the following features.

A classic audio channel, in which half of a 6SN7GT dual triode drives a 304TL through an interstage transformer designed specifically for the 6SN7. With the 6SN7's 7,700 ohms plate resistance, the unloaded output of this interstage transformer is typically flat +/- 1/2 dB from 20 to 90,000 Hz. The amplifier uses no feedback.

All transformers are manufactured to the highest standards of quality, using typical military-standard procedures. Visible transformers are styled with end-bells and have similar appearance to the Stancor, Triad, Thordarson or UTC units of the past. However, the output and the plate transformer end-bells are potted. (Detailed photo of an unpainted output transformer.) Transformers and inductors mounted below chassis use heavy machined aluminum frames and specially designed heavy-duty terminal strips.

Direct current 10 V @ 26 A filament supply with choke-input filter.

1,000 VDC @ 300 mA high voltage power supply with:

866A mercury vapor rectifiers.
Choke-input filter, three LC sections, and oil-filled capacitors.

125 uF capacitor in third section. This capacitor stores 62.5 joules.

Autotransformer control of both filament and plate voltage. This allows the user to warm the filaments slowly and to operate the amplifier at reduced plate voltage and dissipation if desired. A mechanical interlock between the autotransformers allows the knobs to be rotated only in the correct sequence. Operation is fail-safe in the event of a power interruption.

Front-mounted bias controls and plate current meters. This, together with control over the plate voltage, allows the operator to choose the quiescent operating point of the 304TLs.

12 gauge steel chassis, with extensive use of machined aluminum plates and mountings.

3/8 inch thick borosilicate (Pyrex) glass cover.

Gain control and three inputs via pairs of XLR connectors, wired for unbalanced input in the Ampex convention. (Pin 2 is signal ground, pin 3 is signal.)

Convection cooling and quiet operation, with attention paid to audible hum which can be mechanically generated by power components.

Frequency response +/- 1/2 dB from 21 to 20,000 Hz.

Output and damping capabilities:

50 Vpp maximum.
3 ohms effective source impedance.
30 W/channel at 500 Hz and 10 W/channel at 20 Hz into 8 ohms at the 5% total harmonic distortion level.

Voltage gain (no load) 10.

Hum and noise less than 2 mVrms.

Heat dissipation approximately 300 W plus 304TL plate dissipation, which is determined by the quiescent operation point chosen and is 300 W maximum.

Case temperature measurements:

At 100 mA plate current: 38° C temperature rise above ambient (24° C) at the hottest spot, which is the portion of the left side panel directly opposite the left 304TL.

At 150 mA: 41° C temperature rise at the same hottest spot. Typical case temperature rise at this current (at places such as the front of the chassis) is approximately 16° C.

Friday, March 25, 2016

Reezoldini Master R7F

Master R-series

Röhrenschmiede Comet Preamplifier

Röhrenschmiede new preamplifer with OTL headphone amplifier and adjustable phono input.

Thursday, March 24, 2016

Quad Z Series loudspeakers

Quad latest loudspeaker range, the Z Series, is the first of many new products planned for 2016 in celebration of the brand’s 80th year.

The new range combines advanced Kevlar-coned bass and midrange drivers with a ribbon tweeter. The Z Series takes this fundamental design to a whole new level with reengineered drive units, crossovers and cabinets. The range comprises two standmount models (Z-1 and Z-2) and two floorstanders (Z-3 and Z-4).

The Z-1 stands 383mm high and incorporates a 150mm bass/mid cone, while the larger S-2 uses a 175mm bass/mid cone. The two floorstanders sport three-way configurations, coupling a 150mm midrange driver with two 175mm bass drivers in the Z-3, and three 165mm bass drivers in the Z-4.

All Z Series models have a bespoke ribbon tweeter. Like the ribbon unit developed for the S Series, the composite sandwich construction of the Z Series ribbon ensures “it is robust enough to handle high-powered amplifiers”, but at 90x12mm it is significantly larger than the S Series ribbon.

Designed especially for the Z Series, the speakers’ bass and midrange drive units use cones fashioned from woven Kevlar – an exceptionally strong yet light aramid fibre that is as ideally suited to speaker diaphragms as it is body armour. A key feature of these drive units is their unique double-roll cone surround, “which controls breakup modes to enhance accuracy and transparency”, coupled to a cast aluminum basket.

All the Z Series models feature bass reflex loading. This incorporates a dual-chamber filter system inside the cabinet, with the reflex port exiting via a specially shaped expansion chamber in the plinth that is filled with resistive foam. The treble, midrange and bass units are aligned via a phase-compensated Acoustic Butterworth crossover devised using computer-aided design coupled with listening tests.

Every Z Series model cabinet is constructed from multiple layers of wood fibre composites of varying density, extensively strengthened using multiple circumferential braces, all of which reduces panel resonance to “below the level of audibility”. Each speaker is has a piano lacquered finish, made up of multiple layers of piano lacquer, each layer being hand-polished to a high gloss before the next layer is applied.

Recommended retail prices per pair:

Z-1: £1200
Z-2: £1500
Z-3: £2500
Z-4: £3200

Saturday, March 19, 2016

DR Acoustics Pegasus II Silver Ultra Reference Edition


High Quality SafeConn chrome plated stainless steel power plug cover

Exclusive double 4 gauge cable (AWG)

99.99% copper (OFC)

High-performance copper jacket

Silver-plated copper for maximum resolution

2 x 1,800-individual strand conductor

Micro-silicates technology

Male and female rhodium-plated connectors

Available with European plugs (Schuko)

Optional 20-A C19 connector

High-quality nylon outer jacket

Large 45-mm diameter

Length: 1.8 m

Custom lengths available

Weight of 5 kg for a 1.8-m cable

Solid ABS Carrying Case

30-day refund policy

Saturday, March 12, 2016

Wednesday, March 9, 2016

Soundkaos Libération

Libération is a completely open system with no box, so no added colouration.

With a driver array of 2x 8″ full range, dipole ribbon super tweeter and a 15″ woofer per side the soundstage and imaging it presents is astoundingly real and with such a large woofer the low end has superb dimension and scale.

True to the Soundkaos design philosophy it looks as good as it sounds, with most dipole design you end up with a untidy and messy rear end.  Not with Libération, it comes with beautifully finished phosphors bronze covers for both front and rear.

Scheduled for relaese in summer 2016.

Zellaton Legacy at Bristol Sound & Vision 2016


Monday, March 7, 2016