The advanced technology employed in the Elgar Plus makes it possible to give the user a very wide range of additional features and functions beyond that found in ordinary audiophile D/A converters. This gives great flexibility in how the unit may be set up and used in any particular system. A brief look at the main features will confirm this.

The dCS Ring DAC
The heart of the Elgar Plus is its dCS Ring DAC. This is a discrete, proprietary, 5 bit 64 times oversampling architecture. 64 times oversampling means that the actual converter data rate is either 2.822MS/s or 3.072MS/s, depending upon whether the input sample rate is a multiple of 44.1kS/s or 48kS/s. This allows the use of a very gentle and therefore very transparent analogue output filter. The dCS Ring DAC avoids the limitations inherent in the conventional one bit and multibit off-the-shelf converter ICs that are the basis of most other D/A converters. It is a development of work we have done designing A/D converters for fighter airborne radars. Here the performance of the A/D is a major limiting factor in the overall performance of the radar. Only the best will do. Anything less and you risk being blown out of the sky. A brief look at the pros and cons of conventional DAC's, which are generally either one bit, or binary weighted multibit, will make the advantages of the dCS Ring DAC easier to understand.

One bit systems have the advantage of good linearity, but because the converter output is switched between two levels at a very high rate, they are prone to small clock errors, which generate noise and distortion. In addition, their inherently high quantisation noise prevents a very low noise floor from being achieved.

Conventional multibit converters have the advantage of low distortion and noise compared to one bit systems. Their weakness is their dependence on current sources set by a resistor chain within the DAC. If, in a 16 bit converter, the Most Significant Bit current source is i, the next down i/2, the next i/4 and so on, the Least Significant Bit will be i/65,536. Resistors of this required accuracy are very difficult to manufacture, and in any case tend to drift with time and changes in temperature. These problems become more severe as the converter wordlength is increased. Consequently, conventional multibit designs have poor low level linearity and cannot accurately resolve low level signals.

The dCS Ring DAC is a five bit unitary weighted converter. With this design, the problems usually associated with using resistor chains to accurately define extremely small current values that occur in binary weighted multibit types, simply do not exist. Special techniques are employed to cancel residual errors in current source value. It operates at a relatively low over sampling frequency compared to one bit converters, and so avoids the problems resulting from minor variations in high clock speeds. The accuracy of the dCS Ring DAC does not degrade with time, or changes in temperature. Unlike some other DACs, it does not need time consuming and expensive trimming, nor is special selection necessary. The dCS Ring DAC gives consistently excellent performance.

Most importantly, the dCS Ring DAC has exceptional linearity, which it maintains all the way across it's dynamic range. Linearity is a key figure of merit for a D/A converter, that interestingly you will rarely see mentioned in the specifications of audiophile converters. Generally they will be referred to as 24 bit converters, but this simply means that the converter can accept a 24 bit long data word. It does not mean that the converter is able to resolve data in all 24 bits. The Elgar Plus however can. We detail the measurements behind this bold statement in our paper Resolution, Bits, SNR and Linearity.

How does good linearity relate to the sound?
The better the linearity of the D/A converter, the more accurately it will recover the music from the digital source. Conventional D/A converters are quite linear in the upper part of their dynamic range, but become increasing non-linear as the signal level falls. Consequently, low level detail such as room ambience, echo tails and the fine detail that contains the tonal colours in voices and instruments, becomes distorted or even lost. Often, this is not immediately obvious, but with prolonged listening it produces fatigue as the listener becomes aware that something is not quite right.

The dCS Ring DAC’s exceptional linearity enables the Elgar Plus to resolve this fine detail so that the music sounds like music, rather than just a very good reproduction. The music becomes more involving and long listening sessions no longer result in the listener feeling tired at the end. When we ask Elgar Plus users to sum up it’s sound, they often tell us that the Elgar Plus sounds like good analogue. This is not surprising because analogue reproduction systems are quite linear at the bottom end of their dynamic range, which is where conventional D/A converters get into difficulty and where, as explained above, the Elgar Plus has no problems!

Our own extensive listening tests using high quality analogue sources, driving the best A/D converters available (dCS of course) have confirmed that the Elgar Plus really does play music.


Master Mode clock operation
One of the problems of using the standard AES/EBU and SPDIF digital interfaces between a CD transport and a D/A converter, is that the D/A converter has to extract the clock it needs to synchronise its operation from the incoming data stream. This is in itself not a difficult operation. The difficult part is to obtain a stable clock, as the incoming stream will always contain a certain amount of instability, which is referred to as jitter. There are a number of possible sources of jitter. These can include:

• Instability in the digital source's (e.g. CD transport) clock
• Insufficient bandwidth in the digital source's digital output circuitry
• Poor quality or unsuitable digital cable
• Noise and interference
• Insufficient bandwidth in the D/A converter's digital receiver circuitry

The solution to this is not to try and extract the clock from the incoming data, but to drive the transport and the D/A converter from the same clock source, which ideally is located within the D/A converter itself. This is exactly what the Elgar Plus' Master Mode function facilitates. In this mode, the Elgar Plus outputs an ultra-stable clock signal at 44.1kHz, which when used with the dCS Verdi SACD/CD transport or any other transport able to lock to such a signal, enables an even higher level of fidelity to be achieved than when the standard digital interfaces are used.

The result is more precise stereo imaging, better resolution of low level detail and better defined bass.

It should be noted that this method of synchronisation is not a new technique. It is standard practise in the professional recording environment and we have been using it to great effect on our professional products since 1988.

Software and Hardware Upgradable - Don't Fear the Future
Because digital audio formats and interface standards are in a state of flux, it is essential that new digital equipment should be easy to upgrade. Upgrades should also be available at a reasonable cost. All of the major digital processing in the Elgar Plus is carried out in DSP and FPGA ICs. These are software controlled devices that make it very easy to adapt the unit to accommodate changes in digital formats and to add new functions. This was demonstrated when we upgraded the original 24/96 Elgar to 24/192. In this case the upgrade simply involved changing one ROM chip. Whilst some upgrades may also require hardware changes and so be more expensive, it is our policy to make upgrades as inexpensive as we possibly can. New software may loaded into the Elgar Plus from a PC via a rear panel connector, or supplied on a dCS Update CD and loaded by playing it into the Elgar Plus from a CD transport, via one of the unit's PCM digital inputs. This enables software upgrades to be performed without the need to dismantle the unit, or change any parts. Before you buy a new D/A converter, ask the maker about the cost of upgrading to 24/192 and when it will be available. Also ask whether the unit has DSD processing capability already built in and if not what will have to be changed and what will it cost. Remember, the Elgar Plus is already there!

Easy Play Function
The dCS Elgar Plus is a very versatile unit with a large number of features. As time has passed these features have increased in number, which has resulted in the unit being seen by some users as a little bit hard to use, especially when used in conjunction with the dCS Purcell Upsampler and dCS Verdi SACD/CD Transport. The Easy Play function in the latest version of the Elgar Plus software changes all this and makes operation of a dCS system very simple indeed.With a full dCS system, when a hybrid SACD is loaded into the Verdi, it automatically selects the DSD layer of the disc and then all the user has to do is press play. When a CD is loaded into the Verdi, the system automatically sets itself to upsample the CD to DSD and once again all the user has to do is press play.With an Elgar Plus and Verdi system, when a hybrid SACD is loaded into the Verdi, as above, it automatically selects the DSD layer of the disc and then all the user has to do is press play. When a CD is loaded into the Verdi, the Elgar Plus automatically selects a PCM input for 16 bit 44.kS/s playback and once again all the user has to do is press play. Users who require the more advanced features will find them readily accessible as before, via the Function Menu system.

In order to take advantage of the Easy Play function all the dCS units in a system should be fitted with the software versions shown below.
• dCS Elgar Plus Version 4.22 or later
• dCS Purcell Version 2.21 or later
• dCS Verdi Version 1.24 or later

This software is available on dCS Update CDs. These may be obtained from the dCS distributor for your country, or from dCS directly.

8 Digital Inputs
The Elgar Plus is equipped with all of the current standard audiophile digital audio interfaces
• RCA Coaxial
• BNC Coaxial
• AES/EBU x 2
• Toslink Optical
• ST Optical

Each individual input can accept the sample rates 32, 44.1, 48, 88.2 and 96kS/s. In addition, the two AES/EBU inputs can bused in tandem in what is termed Dual AES mode and this configuration covers the sample rates 88.2, 96, 176.4 and 192KS/s. The Elgar Plus is now being shipped with an IEEE1394 interface as standard. This is the digital interface that Sony will use to transfer DSD data between its audiophile products and is the only digital interface permitted for DSD data transfer in the latest version of the SACD specifications. We use IEEE1394 on our dCS Verdi SACD/CD transport and dCS Purcell digital upsampler for DSD data transfer. Earlier dCS Elgars may have the IEEE1394 interface retro-fitted. Subject to a maximum 5 year warranty, all units upgraded with the IEEE1394 interface will benefit from an extension of 3 years to the balance of their existing parts and labour warranty. A new 3 year parts and labour warranty will be given to out of warranty units. For more details please contact us at support@dcsltd.co.uk and give us the serial number of your unit and also let us know where you are located. The Elgar Plus is also fitted with a professional SDIF-2 interface which enables the unit to play back DSD from professional DSD digital sources. This wide range of interfaces, combined with the unit's ability to lock to any standard sample rate from 32kS/s to 192kS/s and accept DSD data, enables the Elgar Plus to be used with almost any currently available, or foreseeable standard audiophile digital source.

Sony DSD Capability
The Elgar Plus is able to accept DSD via an IEEE1394 interface from the dCS Verdi SACD/CD Transport when it is playing the DSD layer on an SACD and also from the dCS Purcell Upsampler when upsampling CDs to DSD. It can also accept DSD data from professional DSD sources such as recorders and editors, via a SDIF-2 digital interface. The Elgar Plus is based on the same hardware as our professional dCS 954 D/A converter, which has had DSD capability since May 1998. A large number of these units are in use in leading recording and mastering studios around the world, where the dCS 954 has been used to make numerous DSD recordings. It is therefore safe to consider the Elgar Plus' DSD processing hardware and software very well proven!
The DSD mode performance of the Elgar Plus will be kept at the leading edge by incorporating improvements developed for the dCS 954 as the opportunity arises.

Digital Volume and Balance Controls
The digital volume controls on conventional D/A converters produce noticeable degradation in sound quality as the volume is reduced from maximum. This is because as the volume is reduced, the DAC is made to work more and more on the less linear part of its characteristic, which leads to an increase in distortion. The dCS Ring DAC maintains excellent linearity throughout its dynamic range, which ensures that the Elgar Plus' digital volume control introduces negligible sonic degradation and this is why the Elgar Plus' digital volume control is widely regarded as the best sounding digital volume control around. For your convenience, an equally good sounding digital balance control is also provided. Both of these controls may be adjusted from the comfort of your chair using the IR remote control.

Absolute Phase Control
A front panel Absolute Phase Control allows the phase of both channels to be inverted. This is useful for correcting recordings that have been made with their phase inverted, or where the playback signal path being used inverts the phase. Phase inversion is performed in the digital domain.

Balanced and Unbalanced Analogue Outputs
The Elgar Plus is equipped with balanced and unbalanced analogue outputs and will happily drive any high quality valve or solid state amplifier. These outputs are fully buffered and both may be used at the same time. Maximum output levels of either 6 volts or 2 volts may be easily selected via a switch on the unit's rear panel. For the ultimate sound quality we recommend that you try listening to the Elgar Plus driving your power amplifier directly. The inherent high quality of the Elgar Plus, combined with the reduction in veiling achieved by simplifying the signal path can be a revelation.

Function Menu
In addition to the functions that are accessed directly via the front panel controls, the Elgar Plus has a large number of addition features and functions that are accessed via what we refer to as the Function Menu. Using the Function Menu, the user can find information about their Elgar Plus and also check and if they require it, change the settings of various operating parameters. The use of the Function Menu makes it very inexpensive and easy to add additional features or functions to the Elgar Plus by simply changing the unit's operating software. Some of the pages in the latest Elgar Plus Function Menu include:
• Digital filter selection - choice of up to 6
• Clock operation selection - Master Mode, Sync Mode, Slave Mode
• Mute and unmute speed selection - choice of 3
• PLL Bandwidth setting - choice of 2
• Factory settings memory
• Channel check signal
• Phase check signal
• Burn in signal
• Digital de-emphassis
• Internal temperature in degrees F or C
• Operating software version number
• DSP board serial number
• Left and right channel swap
• Default display selection - sample rate, volume setting or input
• Balance control setting display selection - numerical, bar graph or dBs

6 User-Selectable Digital Filters
Multiple user-selectable digital filters are available for each sample rate. These effect the frequency response in the ultra-sonic region - above 20kHz. The filters have progressively gentler roll-off characteristics and hence progressively better impulse responses. This leads to an improvement in stereo imaging at the expense of a slight increase in aliasing. All that is perceived timbrally with increasing levels of aliasing, is a progressive, slight increase in brightness in the sound.

• 4 filters are provided for sample rates from 32kS/s to 96kS/s and an additional 2 filters are provided at 176.4kS/s and 192kS/s.
• Filters 1 to 4 are symmetrical filters with their time response before a transition the mirror image of the time response after the transition.
• Filter 5 is a Gaussian filter which has a non-ringing transient response. In other words, there is no ringing, either before or after the initial step.
• Filters 6 is an Asymmetrical filter which has almost no time response prior to the initial step.
• The filters may be selected via the Function Menu using the front panel controls, or via the Infra Red remote control.
• For more information of the significance of filter characteristics on sound quality please see the following dCS Technical Papers:

	• A Suggested Explanation For (Some Of The) Audible Differences Between High Sample Rate and Conventional Sample Rate Audio Material (289KB)
	• Effects in High Sample Rate Audio Material (267KB)

Clock Operation Selection
The user can select from 3 modes of operation for the Elgar Plus' clock circuit.

Slave mode: This is the general purpose setting in which the Elgar Plus extracts the clock signal it needs for its own internal operation from the input digital audio signal. This allows the Elgar Plus to be used with any conventional digital source at sample rates from 32kS/s to 192kS/s. This is the mode that all conventional D/A converters operate in.
Master mode: In this mode the Elgar Plus outputs an ultra-stable 44.1kHz word clock signal that is used to synchronise the digital data source i.e. the CD transport. This can only be used where the digital source is able to lock to this signal. This gives potentially the best sonic performance, as it avoids the jitter than can occur in the digital audio signal when Slave mode is used. Suitable data sources include the dCS Verdi SACD/CD Transport and the Teac P0 and P0-S CD transports.
Sync mode: In this mode the Elgar Plus uses a 44.1kHz word clock signal output by the data source to synchonise its internal clock. This mode is used to allow the Purcell to upsample CDs to DSD when a non dCS CD transport is used.

3 User Selectable Mute Speeds
The Elgar Plus may be set to mute and unmute instantaneously, or to ramp the volume up and down, either slowly or quickly, when the mute button is pressed. Ramping the volume is generally more pleasant to the ear, but in some cases an instantaneous mute may be preferable, for example when carrying out listening tests where the ramping volume levels could be distracting. As always we try to give the user more options.

2 User Selectable Phase Locked Loop (PLL) Bandwidths
An important factor in the performance of a D/A converter is it's ability to reject jitter in the input digital signal. This is determined by performance of the Phase Locked Loop that is used to extract the clock from this signal. The Elgar Plus uses a sophisticated dCS custom designed PLL, combined with specially graded voltage controlled crystal oscillators (VCXOs). The PLL has two user selectable settings. In the "narrow" setting, the PLL turnover frequency is set to an extremely low value. This ensures excellent jitter rejection and gives optimum performance with high quality sources. An additional "wide" setting gives a higher PLL turnover frequency and permits the playback of high jitter sources that might otherwise be unusable.

More information about jitter and it's causes will be found in the following dCS White Paper:
  •Timing Errors and Jitter (88KB)

Factory settings memory
This allows all of the unit's main system settings to be set in one quick and easy step. This greatly simplifies the initial set-up of the unit and enables you to get on with the important business of enjoying music. If you ever become unsure of what your Elgar Plus' settings are, this feature can be useful to restore the unit to a known set-up state.

Channel check
An easy to use channel identification routine enables you to quickly verify that you have the left and right channels in your system correctly connected. This outputs a synthesised 1kHz digital tone, first on the left channel and then on the right channel. At the same time the main display indicates which channel is being tested.

Phase check
A phase check routine allows you to quickly and easily check the phasing of your speakers. This outputs a pink noise signal that is first in phase on both channels and then inverts the phase on one channel. At the same time the main display shows whether the test signal is in phase, or out of phase.

System burn-in signal
A system burn-in signal enables you to use the Elgar Plus to burn-in new items in your system. Having this function and the Channel and Phase checks built into the Elgar Plus means that you will no longer have to turn your listening room up-side-down looking for that elusive test CD.

Digital De-Emphasis
The Elgar Plus has four de-emphasis settings:

• The unit de-emphasises according to codes in the input data.
• Manually selects 50/15µs. This was used on some early CDs.
• Manually selects CCITT J17. This is a broadcast radio standard.
• Performs no de-emphasis regardless of codes in the input data.

The first two modes are of especial interest to the audiophile, as they enable the Elgar Plus to deal with any CD, regardless of whether or not it was recorded with pre-emphasis and also regardless of whether or not the emphasis identification flags in the data stream were correctly set when the CD was mastered. Because the de-emphasis is performed digitally, the filter curves are followed extremely accurately. An additional benefit of using digital de-emphasis filters is that if new digital standards are adopted that require de-emphasis, it will be very easy to update the Elgar Plus to accommodate this. On D/A converters where the de-emphasis filtering is implemented in the analogue domain, any update will require potentially expensive hardware and software changes.

7 Display Brightness Settings
A 7 level brightness control allows the display brightness to be set to match the ambient light level in your listening room. For the purists, it is also possible to switch the display off completely.

Self Test
Every time the Elgar Plus is switched on, it automatically performs a rigorous self test on its digital processing system. It also constantly analyses the input signal and flags errors if they occur. This can be very useful in trouble shooting problems with digital sources.

Parameter Memory
When the Elgar Plus is switched off, all of the unit's settings such as Volume, Balance, Digital Filter, Mute Speed, Display Brightness etc are saved in a non-volatile memory. These are restored when the unit is next switched on and this removes the need to reset all of the parameters each time the unit is used.

Infra Red Remote Control
The remote control provided with the Elgar Plus allows you to control all of the unit's front panel settings and the digital filter selection from the comfort of your chair. It is also compatible with the dCS Purcell Digital Upsampler.

1 Year guarantee
The Elgar plus, like all dCS audiophile products, is guaranteed for 1 year from the date of purchase if the unit is purchased from an authorised dCS dealer. The guarantee is transferable to subsequent owners. Elgar plus owners who register their purchase with dCS will be notified when upgrades become available.

And Finally....
You've read the sales pitch. Now go down to your nearest dCS dealer and hear the reality. Don't forget to take some of your favourite CDs and SACDs with you.

Go on, let us make your day

Specification: