Q 2 • 2009

In this issue: Upgrade your system • Active crossovers Comments from the press • Q&As

Sound Reasons

Benefits of transformer balanced outputs

DEQX’s transformer-balanced output module has important advantages over standard active-balanced output boards.

Transformers offer galvanic isolation of earth noise (often compounded by interaction between multiple pieces of equipment) that active balanced circuits cannot provide.

The six Jensen output transformers used in DEQX’s output module were chosen for their acoustic transparency and additional attenuation of frequencies above about 50kHz, which further attenuate the high frequency switching noise generated by all sigma-delta DACs (>1MHz).

The PDC-2.6 and HDP3 already use high quality, low-pass filters that follow each of their six DACs, but the additional high frequency attenuation provided by the transformers is also advantageous when driving D-class amplifiers, which also generate out-of-band switching noise above about 300KHz.

When the >1MHz DAC switching frequency modulate with the various 300kHz-400kHz D-class amplifier switching frequencies, low levels of the resulting aliasing demodulate into the audio region undesirably.

We find the new transformer-balanced output module outperforms our standard active- balanced output module and even the new HD active-balanced output module.

As DEQX always looks to give existing users an affordable performance upgrade path, we are offering—for a limited time—the new transformer output module at a 15% discount from the Australian dollar list price. And a $300* trade in for your standard balanced output module or $400* for an HD balanced output module.

With favourable exchange rates for US$ and Euro’s against the Australian dollar, it’s worth getting this self-installable upgrade.

Crossovers WHY go active?

Many DEQX owners first use their PDC or HDP preamp-processor to correct their passive speakers, capitalizing on its unique time and frequency domain processing capabilities.

This produces great results, but additional benefits can come from engaging the active crossover features; running each driver (bass, mid, tweeter) independently via dedicated power amplifiers…read more

Show us your capacitors

A brief history of DEQX by Kim Ryrie

We’re often asked how DEQX came to be and, especially, how it came from Down Under…

I remember being amazed, many years ago, that a piece of rolled up paper or cardboard, moving backwards and forwards inside a magnetic field, could reproduce sound with seemingly uncanny accuracy (I suspect that fascination remains strong for most of us trying to create the most realistic sound experience possible). …read more

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Where in time is your
sub-woofer By Doctor Who

As progress on the latest version of the DEQX cal software continues, we have found some useful tools available in the current release version of DEQX cal v2.01 & v2.58 for time-aligning separated subwoofers with main speakers.

This process time aligns the sub-woofer with the main single or bi-amp speakers using the standard room measurement. The resulting impulse display for the main speaker and subwoofer can bee seen in the ‘viewer’, indicating any difference between the two impulse responses, which can then be added to the leading speaker so that both are perfectly aligned. …read more

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COMMENTS FROM THE PRESS

The rooms that we found to be safe-havens from the stress of the showin that they sounded really good are designated as being an Audio Oasis.

While at the CES 2009 show there were a number of exhibitors using DEQX processing in their rooms. A number of show reports note the great sound in a number of these room. Again the Sonicweld Pulserod system received an Audio Oasis along with Acoustic Zen & Triode Corporation from Dave & Carol Clark of Positive Feedback.

The Acoustic Zen / Triode room used the DEQX between the Triode valve pre-amp and the mono block valve power amplifiers while transparently maintaining the sound character of
the valve electronics.