REDGUM RGDAC8

Clearly, a USB DAC has no need to pretend it is trying to be “the world’s most advanced DAC, ever”! But when it presents as a Signature Series Hi-res USB DAC, it does show a determination to maintain digital accuracy, most particularly when it is an Asynchronous DAC.

The sonics of REDGUM CDP/DAC designs have long been trusted, remarkably, because of their asynchronous-ness. And that history began in 1997, decades before that term became widely used!

In brief, REDGUM’s RGDAC2 & RGDAC5 have been asynchronous from their first design as their digital stream was (and remains) fully reclocked and reshaped in a separate, additional chip. This additional chip also provides the buffer for the storage of the data stream in real time, thus removing the problem of jitter.

A USB input has been a feature of REDGUM DAC and CD Player models for some years now, so to build on that history, the next product could only bring all these features together. And then some! Especially when ear-tuned to be at least the match of the sonic quality of our (then) top-line RGDAC5 (also used in the RGCD5ENR CD Player).

We proudly present the RGDAC8 as our Signature Series Multi-format Asynchronous Hi-res USB DAC, complete with a two metre dedicated USB Cable with gold-plated connectors and blue LED, plus a one metre REDGUM RGAP 1 “Audio Pipeline” OFC Interconnect .

(H 50 x W 113 x D 142 mm / H 2 x W 4.5 x D 5.6 in – 1.1kg / 2.4lb – 1 Year Warranty – available in Black or Silver)

Fun Fact:
There is enough power “in” the USB cable to supply 60 REDGUM DACs together! … which means the RGDAC8 does not require any power cord to play along as part of your system. So that makes it even easier to slip this DAC into your rack! Having a 2m long USB cable at one end of the DAC and a 1m RCA cable at the other makes it a very flexible set-up to find a comfortable position. And that could be anywhere on your shelf (e.g. on its side next to, or behind, any unit) as the little heat generated by the RGDAC8 is almost indiscernible.

Serving Suggestion:
Presented together as the Aggregata Stack, the Signature Series RGDAC8 is at its best with its performance soul mate, REDGUM’s Media Player, the RGMP8. (For the Stack, in matching Black only.)

And as to how much “soul” they reveal together …  see review by Soundstage! Australia.

Some Background to its extra Special Somethings

From Beta-test to adding the Sonic MSG of the AAS

REDGUM ‘s hi-res DAC was initially released in its Beta-test form as the BlackDac 8 in October 2016 at the Australian Audio & Hifi Show. No toe-in-the-water affair, this Beta-test design was upstream at the World Premiere of REDGUM’s flagship Magnificata Pre/Power system!

With several major Shows following, it wasn’t until the Melbourne International HiFi Show 2017 that the final version appeared, now designated as the RGDAC8. In a chassis with smoother lines, internally the same main circuit board was now in the company of an additional pcb, REDGUM’s own Advanced Audio Stage (AAS). Its designer considered that this finer-tweaking pcb revealed even more musical detail – like adding a goodly pinch of sonic MSG.

And the recipe? It became a clear case of looking to the past to build the future. From the start, all in-house Beta-stage listening was referenced back to the sound of REDGUM’s top-line Signature Series DAC, the RGDAC5. The RGDAC5 and (as its CDP) the RGCD5ENR have always used the Rolls Royce of Burr Brown DAC chips – the PCM1702.

From that high Redbook standard, the ears of any listener would already be beautifully spoilt by the time they were moving on to hi-res files. But it was realised that a final tweak would still be needed to remove the digital “glare” that is too often an element of hi-res files.

The slightest hint of any in-your-face digital “edginess” definitely needed to be brought under control if the RGDAC8 was to be considered (at the very least) the equal of the RGDAC5. For that final tweak to free up the revelation, the REDGUM magic of the AAS pcb was devised. Just like making a finely-balanced curry, it is all in the tweaking! (And you know you can’t ask the chef his secret!)

But with a RGDAC8, you can play with some of his spices by …

Personalised Filter Shaping – a Tweaker’s delight

As everyone likes to tweak DAC values these days, the RGDAC8 has been designed so that the output stage filter can be adjusted by the user, if wished. As standard, each unit includes a matched set of small capacitors to adjust the filter shaping, thus covering a range of carefully-determined sonic options.

Clearly that is not where a new owner starts the process of assessing the unit, but along the way it is likely that some users will enjoy the option of modifying the tonal balance as their “inner designer” comes to the fore! In addition, this possibility allows for any change in personal preferences and/or their system over the years. Once again, that old mainstay of REDGUM designs becomes apparent, whereby its minimalism aims to provide future-proofing as much as sonic quality.

To make any adjustment is as simple as removing the base plate of the RGDAC8 to reveal these caps in a cellophane bag! (And yes, the bag does rattle gently if the unit is shaken, but that should not intrude whilst it sits on a shelf.) The existing caps can easily be removed by hand from their gold-plated machine-pin push-in socket and replaced with the paired alternatives provided. (However, if preferred, these caps can safely be ignored for the rest of the product’s days!)

N.B. Making these adjustments does not void the warranty unless there is clear evidence of a lack of care.

The range of values covered by the caps has been “Goldilocks-ed”. To REDGUM ears, the pair fitted as factory-standard is “Just right!”. Depending on what change you seek when choosing an alternative matched pair, note that the lower the value inserted, the brighter the sound quality; the higher the value, the duller the resultant change to the sound. With a total of six options, let your ears finesse the RGDAC8 till it has “your” sound as it “plays nicely together” with the rest of your system.

RGDAC8 Specifications: – Signature Series Multi-format Asynchronous Hi-res USB DAC

Data rate maximum speed: 384kHz
Bit depth maximum: 32bit

USB Audio Streaming Controller – SA9227:

Supports 16/24/32 Bit resolution and sampling rates of 32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz, 352.8kHz, 384kHz.

THD <0.005% (including noise component)
S/N ratio > 95dB

Audio Stereo DAC PCM5102A :

2VRMS DirectPath™, 112dB Audio Stereo DAC with 32bit, 384kHz PCM Interface

SNR 112dB
Dynamic range 112dB
THD N at –1 dBFS –93dB
Full-scale single-ended output
2.1 V RMS (GND center)
Normal 8× oversampling digital filter latency 20t S
Low latency 8× oversampling digital filter latency 3.5t S
Sampling frequency 8kHz to 384kHz
System clock multiples (f SCK ): 64, 128, 192, 256, 384,
512, 768, 1024, 1152, 1536, 2048, 3072 up to 50MHz

N.B.
– Apple MAC and Linux-based computers do not require any extra drivers.
– Only earlier Windows-based units may require a special driver, available at https://www.redgumaudio.com/Download/RGDac8.zip