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Product Review - Assemblage DAC 3.1 and D2D-1 Sample Rate Converter - July, 2001

John E. Johnson, Jr.


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Specifications:

DAC 3.1

DACs: 24/96, Fully Balanced

Digital Inputs: I2S-e, XLR, BNC, RCA, Glass ST, Glass Toslink

MFR: 20 Hz - 20 kHz at 44.1 kHz, 20 Hz - 45 kHz at 96 kHz

Jitter: 2 ps

Size: 3" H x 14" W x 10" D

Weight: 12 Pounds

MSRP:   $1,599 to $2,698 USA Depending on Upgrades

D2D-1 Sample Rate Converter

Resolution: 24/96

Digital Inputs: I2S-e, XLR, BNC, RCA, Glass ST, Glass Toslink

Jitter Reduction: Beginning at 10 Hz

Size: 1 3/4" H x 9 1/2" W x 8 1/2" D

Weight: 8 Pounds

MSRP:   $699 USA

 

 

 

 

The Parts Connection, 3535 Laird Road, Unit # 16, Mississauga, Ontario, CANADA L5L 5Y7; Phone 905-828-4575; Fax 905-828-4585; E-Mail sales@partsconnection.on.ca; Web http://www.partsconnection.on.ca 

Introduction

As you have all seen from the recent reviews in Secrets, more and more companies are offering hi-fi products factory direct on the Internet. The problem of encroaching on dealerships is dealt with by designing a product with a different brand name or model, only offering it on the web, while maintaining the regular product line only in dealer showrooms.

Assemblage is a product line offered by Sonic Frontiers, International, through their website called The Parts Connection. They sell all kinds of electronic parts for DIYers, but also kits and assembled components (thus the name Assemblage). Sonic Frontiers amplifiers is a name we all know, and those products are available through dealers.

The Assemblage Products

We obtained for review, the Assemblage DAC 3.1 Platinum and the D2D-1 Sample Rate Converter. The basic 3.1 is available as a kit for $1,599, but the Platinum Edition, which we had for review, is only available as an assembled unit, for $2,698. Even $1,599 sounds like a lot of money for a DAC, but the parts for this unit, and especially the Platinum Edition, are very expensive. After all, you can buy an assembled DAC for just a few hundred dollars from other companies, but take a look inside the chassis, and you will see big differences.

So, what do you get with the 3.1? Well, for starters, there are two top of the line Burr-Brown 24/96 DAC chips per channel (the 3.1 is a stereo DAC, i.e., two channels, not a 5.1 product). The entire circuit is fully balanced from front to back. I should note that 24/96 stereo DAC chips can be purchased for just a few dollars. The particular DACs in the 3.1 are Burr-Brown's best, with very low harmonic distortion. These chips are found in DACs costing in the range of $10,000.

The front panel of the 3.1 has push buttons for power on/off, phase normal or invert, input, and mute. LEDs indicate the input, phase, lock, de-emphasis, and HDCD.

The photo above shows a view of the inside of the 3.1 chassis. The power supply is substantial, which means it will drive the input of a preamplifier even if it is not high impedance. There are three toroidal transformers and 40,000 F of power supply capacitance. Secondly, there is an extensive amount of circuitry to maintain the signal with very low jitter. Although jitter is a controversial subject, I would rather have low jitter than high jitter, wouldn't you? And, the 3.1 spec is very low (2 picoseconds, or ps).

The PC boards are four-layered, meaning that circuitry is in one of four layers. This allows for very short signal paths. The power distribution is in the middle layers.

The rear panel of the 3.1 has a multitude of inputs, in fact, pretty much any type of input you could encounter. In particular, there is an I2S-e (e for enhanced). A photo of this connector is shown below, which looks like a modified DB-25, and is called a 13w3 (it's used in workstation monitors for companies like Sun Microsystems and Silicon Graphics). The advantage of the connector is ultra-low jitter.

The D2D-1 Sample Rate Converter is an add-on product, which will allow you to input a 16/44.1 digital signal, and convert it to 24/96. This is then sent to the 3.1 DAC which treats it as a native 24/96 signal. The D2D-1 also reduces the jitter, if the output from your transport has significant amounts of it, but the primary function is as an upsampler.

The photo above shows the inside of the D2D-1. Again, a substantial power supply is evident. The rear panel of the D2D-1 has a full range of digital inputs and outputs. When the D2D-1 and DAC 3.1 are powered up, inputs are automatically selected, depending on which connection you have in place. The I2S-e cable is about $50. It is rather difficult to insert properly, so be careful.

So, why not put the D2D-1 and 3.1 circuitry all in one chassis? It would take up too much space, and the resulting component would be too big

The Sound

I tested the D2D-1 and DAC 3.1 using a McCormack CD transport, Balanced Audio Technology VK-5i Preamplifier, Balanced Audio Technology VK-500 Power Amplifier, McIntosh 602 Power Amplifier, Carver Platinum MK-IV Speakers, and Nordost Cables.

I continue to be amazed at improvements that are made with conventional CD performance. Although 24/96 DVD-A and SACD are certainly better, there is still something to be wrung from all of our old CD collections. The Assemblage combination brought out an astonishing amount of detail from those old CDs. My favorite disc for testing new products is one of my oldest: the Telarc version of Copland's Fanfare for the Common Man. The trumpets on this recording will make manifest any harshness in any component of the signal chain, and with the Assemblage setup, there simply was none. Crystal clear is the only way I can state it.

The Narada collection of guitar music is another favorite here in our lab. The transients at the edges of steel string guitar plucks, as well as the sustains, are very demanding. Truly, there was nothing on this disc that the Assemblage could not handle. Switching between 44.1 kHz output to 96 kHz output increased the body of the music. Of course, the up-sampling is based on mathematic assumptions, but it does seem to work. I did not notice an improvement when using the I2S-e cable, indicating that the jitter handling of the 3.1 was already very good. So, I settled down to using a digital RCA coax cable.

Voices are always an important test vehicle. I like throaty singing, such as the silver haired Tony Bennett. Even though he is still pure gold, age has brought a rasp, and only the best equipment will bring out all of it. The Assemblage does so with aplomb. His drummer uses some very dark cymbals, and the stick detail is difficult for some components to pass. However, the D2D-1 and 3.1 presented it with every nuance.

We also listened to many other discs, and the results were always the same: very fine detail.

Conclusion

Even though DVD-A and SACD are upon us, there is still reason to buy into product quality for our huge collections of standard CDs. The Assemblage line of components allows you to get a $10,000 sound for about a quarter of that. It is great to know that companies are still perfecting their conventional DAC designs instead of abandoning them for work on multi-channel surround formats.

 

- John E. Johnson, Jr. - 

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Copyright 2001 Secrets of Home Theater & High Fidelity
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