AfterDark Giesemann Trifecta Emperor Double Crown 10 MHz Clock - Review

[DarqueKnight]

Part 1. Introduction

 

The stereophonic performance of an AfterDark Giesemann Trifecta Emperor Double Crown 10 MHz clock (AD EDC) ($2681 USD ) was evaluated in my main home stereo system. The AD EDC was purchased as a performance enhancement accessory for an Uptone Audio EtherREGEN (ER) audiophile Ethernet switch. The AD EDC's performance was compared to that of a BG7TBL 10 MHz clock ($85 USD), an AfterDark Gieseman Queen 10 MHz clock ($751 USD), and the internal clock of the ER switch, a Crystek CCHD-575 25 MHz clock. The ER retails for $650 USD. Phase noise specifications for each clock are given in table 1. The BG7TBL clocks ( I own two) were purchased for proof of concept experiments. The AD Queen clock was purchased for my office stereo system. The AD EDC clock was purchased for my main home stereo system.

 

Figure 1. AfterDark Emperor Double Crown front. To my disappointment, there is no LED or other visual indication that the unit is turned on.

 

Figure 2. AfterDark Emperor Double Crown top view. The AD EDC features high build quality with a chassis made of aluminum and carbon fiber panels. An internal custom R-Core linear power supply is included.

 

Figure 3. AfterDark Emperor Double Crown rear view. Three isolated 75 ohm outputs.

Crystek published a 10 Hz phase noise specification of -100 dBc/Hz. A 1 Hz specification was not provided. Since the ER's Crystek clock runs at 25 MHz, some extrapolation was used to derive a 10 Hz phase specification at 10 MHz. Alex Crespi of Uptone Audio explained as follows:

 

"The Crystal CCHD-575 [used in the EtherREGEN] is one of the lowest phase-noise production XO available (about $10 each at 500 piece qty,), and our 3 original 25MHz (random production) samples came with plots showing 10Hz-offset phase-noise of -108, -110, and -112 dBc/Hz.  (Crystek is very conservative and the graphs they post do not reflect these actual terrific production performance marks.) And remember, it is far easier to get better numbers from a 10MHz clock than a 25MHz clock, though they can be equivalent in terms of jitter/phase-noise.

 

-125dBc/Hz @10Hz is about what it takes for a 10Mhz clock to audibly surpass the EtherREGEN's 25.0MHz Crystek CCHD-575.  25.0MHz is 1.5 octaves above 10.0MHz, so its typical -110dBc/Hz (@ 10Hz offset) can be considered equivalent to -119dBc/Hz if it was a 10MHz clock (about 6dB/octave is safe to draw comparisons between frequencies). And it seems plausible that the adjusted-for-frequency difference of 6dB--between -119 and -125--would be about the threshold for what could be audible with our switch.

This assumes use of a good short clock cable, matched impedances, and use of square wave..."

 

Link: https://audiophilestyle.com/forums/topic/59419-master-clock-for-your-etherregen/page/23/?tab=comments#comment-1102343

 

Figure 4. The BG7TBL clock uses a Symmetricom 090-03861-13 OCXO. Repeated requests to Symmetricom for phase noise specifications for this OCXO were ignored. I did find a phase noise plot for a Symmetricom 090-03861-13 OCXO in an eBay ad. That plot is shown in figure 6.

 

Figure 5. Phase noise plot for Crystek CCHD-575 25 MHz clock.

 

Figure 6. Phase noise plot for a Symmetricom 090-03861-13 found in an eBay ad.

 

AfterDark provides a certificate of calibration with each of their clocks. The certificate includes the phase noise plot, phase noise specifications at 1 Hz and 10 Hz, and the Allan Deviation chart.

Figures 7 and 8 are the calibration certificates that came with my AD Queen and AD EDC clocks.

Figure 7. Phase noise plot and specifications for AfterDark Queen clock.

 

Figure 8. Phase noise plot and specifications for AfterDark Emperor Double Crown clock.

 

Part 2. Measurement Evaluation Setup

 

A Tektronix TDS 2012 oscilloscope was used to plot square wave outputs of each clock. The clock cable was a 2 meter AfterDark Black River 75 ohm cable. At the time of evaluation, the AD EDC had been in service for 64 days. The Queen and BG7TBL clocks had been in service for 12 days. Each clock was fed by a Signal Cable MagicPower cord connected to a PS Audio P10 AC regenerator. Clock swaps were done by disconnecting the EtherREGEN's power cable, connecting its clock cable to a different clock, then reconnecting the EtherREGEN's power cable. The clocks were not turned off or disconnected from power during the swaps.

 

Figure 9. Evaluation setup for measurements.

 

Figure 10. The AfterDark Queen clock and the BG7TBL clock were powered with Teradak DC-50W linear power supplies (12V/4A).

 

Figure 11. Rear views of BG7TBL and AD Queen clocks.

 

Figure 12. BG7TBL clock square wave pulse train.

 

Figure 13. BG7TBL clock square wave pulse.

 

Figure 14. AD Queen clock square wave pulse train.

 

Figure 15. AD Queen clock square wave pulse.

 

Figure 16. AD Emperor Double Crown clock square wave pulse train.

 

Figure 17. AD Emperor Double Crown clock square wave pulse.

 

Part 3. Stereo System Details

 

Figure 18. Listening room, 21 feet wide by 17 feet deep with a 10 foot ceiling. The listening seat is 12 feet from the front plane of the speakers.

 

Figure 19. View from listening seat.

 

Figure 20. Digital source components, left to right: dCS Debussy Dac, dCS Puccini U-Clock word clock, Synology DS718+ NAS, Bryston BDP-3 digital player. All CDs and vinyl records were converted to single rate DSD (.dsf) files and stored on the NAS. The EtherREGEN sits at the top rear of the Puccini U-Clock.

 

Figure 21. Block diagram of digital source component connections. The NAS is fed by a TeraDak DC-150VA linear power supply. The EtherREGEN is fed by a Farad Super3 linear power supply. The DAC, U-Clock, BDP-3, XP-30 preamp, and linear power supplies are fed clean regenerated AC power from a PS Audio P10 AC regenerator. The Pass Labs X600.5 monoblock power amps are each fed by a dedicated 20 amp AC circuit and are plugged into the wall. The P10 regenerator is on a third dedicated 20 amp AC circuit. An Araknis AN-110-R8 Ethernet switch provides connectivity to the home LAN. The Araknis switch is on a different (non-dedicated) AC circuit.

 

Part 4. Stereophonic Performance Evaluations

 

For sound quality evaluations, a single musical selection was used: "Healing Song" from Gregg Karukas' "Heatwave (2002)" CD. This selection comprises the following instruments:

 

1. Acoustic piano (Gregg Karukas).

2. Synthesized organ (Gregg Karukas).

3. Synthesized guitar (Gregg Karukas).

4. Tenor saxophone (Kirk Whalum).

5. Electric bass (Jervonny Collier).

6. Various percussion instruments (Lewis Conte).

7. Drums (John Lewis).

 

The musical selection was played many times, with each clock, in order to map the placement of sound images in the sound stage and to describe the character and quality of those sound images. Summaries of the sound evaluations with each clock are given in figures 22 through 26. Listening was done at an average sound level of 85 dBc, measured with a Radio Shack analog sound level meter.

 

Figure 22. Aerial sound stage map with EtherREGEN and its internal Crysek CCHD-575 clock.

 

Figure 23. Aerial sound stage map with EtherREGEN and BG7TBL clock.

 

Figure 24. Aerial sound stage map with EtherREGEN and AfterDark Queen clock.

 

Figure 25. Aerial sound stage map with EtherREGEN and AfterDark Emperor Double Crown clock.

 

Figure 26. Lateral sound stage map with EtherREGEN and AfterDark Emperor Double Crown clock.

 

 

In summary, as I went up in clock quality, the bass became deeper, more defined, more tactile, and more articulate. Overall clarity and detail improved. Sound images became heavier, more dynamic, and more representative of actual instruments playing in a live space.

 

Part 5. Power Cables And Power Supplies

 

I was hoping to get off easy with a (relatively) cheap power cord for the AD EDC clock, but I did not have any luck in that regard. After my primary evaluations were completed, attention was turned to investigating power cord upgrades. Prior to the formal listening evaluations, the AD EDC's stock 16 AWG power cord was replaced with a 3 foot 10 AWG Signal Cable MagicPower cord. The list of power cords evaluated with the Emperor Double Crown clock, listed in order of decreasing sound quality, is as follows:

 

1. PS Audio AC-12, 1 meter, 8 AWG, $800 USD.

2. PS Audio AC-10, 1 meter, 10 AWG, $500 USD.

3. PS Audio Premier SC, 1 meter, 7 AWG, $1000 USD.

4. PS Audio AC-5, 1.5 meter, 10 AWG, $300.

5. Signal Cable MagicPower, 3 feet, 10 AWG, $89 USD.

6. Stock power cord, 6 feet, price unknown, probably less than $5 USD.

 

Figure 27. Emperor Double Crown clock power cord candidates, top to bottom: PS Audio AC-12, PS Audio AC-10, PS Audio Premier SC, 1 meter, PS Audio AC-5, Signal Cable MagicPower, Stock power cord. Better power cords delivered better bass and other sonic treats.

 

I found that a TeraDak DC-30 (12V/2A, $90)  linear power supply provided better sound (and video) quality compared to the EtherREGEN's stock switch mode power supply. A TeraDak DC-50W (12V/4A, $145) outperformed the DC-30. A Farad Super3 (12V/3A, $1100) linear power supply significantly outperformed the DC-50W. All three LPSs benefited from higher quality power cords. The Super3 to a much greater extent than the TeraDak LPSs.

 

Part 6. Clock Economics

 

From the outside looking in, it might seem irrational to buy a $2651 audio(phile) accessory for another audio(phile) accessory that costs $650. However, in terms of the big picture, and in terms of my stereophonic listening pleasure, it makes sense. I think of my computer audio home stereo system as analogous to a "digital house" where major components (amplifiers, source components, loudpeakers) are like "rooms". Cables are like "hallways", switches are like "doors", isolation devices are like "fine flooring" and "soundproofing", and clocks are like...clocks that improve the efficiency of the digital house's operations. In that context, the EtherREGEN switch and its 12.5X more expensive associated accessories (clock, power supply, cables) are seen as parts of a single modular component. Even more than that, it is good to be ready for the future, when an even better audiophile Ethernet switch will come to market.

 

Figure 28. Installed on the second shelf of my audio equipment credenza. The AfterDark Giesemann Trifecta Emperor Double Crown 10 MHz clock was a right proper addition to my "digital house".

 

Part 7. Associated Equipment

 

Bryston BDP-3 Digital Player

dCS Debussy DAC

dCS Puccini U-Clock Word Clock

PS Audio PowerBase Isolation Platforms for BDP-3, Debussy DAC, P-10 AC Regenerator, and Puccini U-Clock

Black Diamond Racing Mk3 Mini Isolation Pits And Mk4 Isolation Cones For BDP-3, Debussy DAC, and Puccini U-Clock

Pass Labs XP-30 Line Level Preamplifier

Pass Labs X600.5 Monoblock Power Amplifiers

Synology DS718+ Network Attached Storage with two Western Digital Red 6 TB Drives in RAID 1 configuration

TeraDak DC-150VA Linear Power Supply for DS178+ NAS

Uptone Audio EtherREGEN Ethernet Switch for NAS and Digital Player

Farad Super3 Linear Power Supply, with 1m Level 2 Silver DC Power Cable, for EtherREGEN

Araknis AN-110-SW-R8 Ethernet Switch for connectivity to home LAN

Revelation Audio Labs Prophecy Cryo-Silver Split Configuration USB Cable

Revelation Audio Labs Passage Cryo-Silver DB-25 Power Umbilicals for XP30 Preamp

Revelation Audio Labs Cat8+ Ethernet Cables, 1.25m, for BDP-3 to EtherRegen and for NAS to EtherREGEN

Revelation Audio Labs Prophecy CryoSilver Reference S/PDIF Digital Link Cable - U-Clock To Debussy DAC - RCA Terminations (Audio Signal)

AfterDark Giesemann Black River 2m 75 Ohm Clock Cables for U-Clock and Emperor Double Crown Clock

AudioQuest Sky Generation 2 XLR Interconnects

AudioQuest Everest 9 AWG Hyper-Litz Speaker Cables

PS Audio PerfectWave AC-12 Power Cords for Amplifiers and Source Components

PS Audio AC-5 Power Cord for TeraDak DC-150VA Linear Power Supply

PS Audio PerfectWave P-10 AC Regenerator (for Source Components and Preamplifier only)

Polk Audio SDA SRS 1.2TL Loudspeakers (Heavily Modified)

Dreadnought Non-Common Ground Interface (Avel-Lindberg Audio Grade 1000VA Isolation Transformer) for SDA SRS 1.2TL Loudspeakers

HiFi Tuning Supreme Power Line Fuses for Debussy DAC, P-10 AC Regenerator, Puccini U-Clock, BDP-3 Digital Player, and Super3 Linear Power Supply

Salamander Synergy Triple 30 Audio Credenza

Dell Venue Pro 7140 Docked Tablet Computer for Controlling BDP-3 Digital Player, NAS, and AC Regenerator

Three Dedicated 20 Amp AC Circuits, one for each power amplifier, one for the P10 AC Regenerator (Source Components, and Preamplifier)

Three PS Audio Soloist SE In-Wall Passive Power Conditioners, one for each dedicated AC circuit

 

 

 

 

[DarqueKnight]

4 hours ago, Iving said:

I experienced a protracted and significant burn-in journey - but this was associated with a multitude of simultaneous upgrades. Settling-in lasted maybe 40-50 days.

Your square wave oscilloscope images show the Triple has a flatter top than the BG7TBL or the AD Queen. Commentary? What do you think - or are you happy that readers draw the simple conclusion that the Triple EDC has a better square shape?

Those listening tests are pretty detailed and exhaustive. Must've involved a lot of work. I can follow your notes. Texture, depth, I want to use "reverberation" but really I mean "sustain" (not distortion).

The gist - SQ correlates in expected ways (and proportionately) with phase noise.

I'm still mucking about with speaker placement and its repercussions for bass, image, freq. emphasis around mids - so I don't have sound stage remarks ass. with the clock.

Sorry if I missed it - why did you get the Triple (cf. single out for ER). Do you use just one out even now in your whole system.

Are you thinking of upgrading the internal R-Core linear power supply of the Triple EDC at any point. Have you asked Adrian about this. Voltage? Please do share any relevant info.

I agree value for money. A Mutec REF10 would have been 2 x cost.

When you say "it is good to be ready for the future, when an even better audiophile Ethernet switch will come to market", I presume you are referring to PMs with Alex ;-)

Thank you for the link to your excellently detailed review of the Emperor Double Crown and subsequent posts.

 

Addressing your questions and comments:

 

1. Prior evaluations have shown that a clock's square wave shape can depend a lot on the cable. Furthermore, I have not found reliably consistent evidence that a squarer wave shape always correlates with better sound quality. However, @JohnSwenson noted that irregularities in the square wave shape can be an indication of impedance mismatches, which do affect sound quality:

 

https://audiophilestyle.com/forums/topic/59419-master-clock-for-your-etherregen/page/47/?tab=comments#comment-1122787

 

2. My listening evaluation methodology is a lot of work, but it provides a lot of documentation that relieves me of the burden of having to rely totally on memory for a current and future evaluations. It also relieves me of the burden of trying to "hear a difference" during a listening session. I do not listen for differences. I listen to document everything that is heard, then compare notes. I often do not become aware of differences until listening notes and sound stage maps are compared. This is especially true of more subtle differences such as small changes in image placement, changes in ambient cues, and changes in background instruments.

 

3. I only use one of the EDC's three outputs. I wanted a three output clock in case the need arises in the future. The Puccini word clock has four outputs. I thought the 10 MHz reference clock should have multiple outputs as well. The digital source in my main stereo system seems to grow over time:

 

A. SACD player.

B. Digital player (music files stored on internal solid state drive) + DAC .

C. Digital player + external hard drive for music files + DAC + word clock.

D. Digital player + DAC + word clock + NAS + switch.

E. Digital player + DAC + word clock + NAS + NAS LPS +switch + switch LPS.

F. Digital player + DAC + word clock + NAS + NAS LPS +switch + switch LPS + 10 MHz clock for switch.

 

Who knows what the future holds? I do not mind the "digital proliferation". Rather all that than the tyranny of disc-based playback. My main stereo system circa 2013:

 

 

4. I did ask Adrian about bypassing or upgrading the EDC's internal linear power supply. He did not recommend it because the EDC's power supply was custom designed and tweaked to optimize the performance of the clock's OCXO. For now, I will assume that AfterDark knew what they were doing when they included a built-in LPS for the EDC clock.

 

5. My "it's good to be ready for the future" comment alluded to comments made by @Superdad :

 

"If we were to get fancy and situate an EtherREGEN (with further functional and performance enhancements) in a large case with power supplies and top-end clock, it would have to retail for about $3K (with a build cost that would have other firms charge $5K for).

 

John and I would much rather have thousands of people able to enter and benefit at a low price than to only offer something extreme that far fewer can afford. 

 

We might go there someday—as we know we are leaving money on the table since we see there are those anxious to spend big bucks."

 

https://audiophilestyle.com/forums/topic/59419-master-clock-for-your-etherregen/page/49/?tab=comments#comment-1124544

 

 

[DarqueKnight]

@GuyinOz

 

I only have personal experience with two AfterDark clocks, but, according to AfterDark, the sweet spot in their clock lineup is the Emperor Signature level:

 

This is where the Emperor Signature falls in the lineup: