A friend recently recommended I get the
Audioquest Diamondback RCA interconnects ($70 for a 0.5m pair).
When I went to Audioquest's web page, I couldn't find any mention of the Diamondback.
I could find "Audioquest Diamondback" using Google - with a lot of hits at eBay and elsewhere, but I could not find any mention of the Diamondback at Audioquest's own web page for analog interconnects:
http://www.audioquest.com/analog-interconnects/
Then I tried searching Google by specifying the site, as follows:
"site:
www.audioquest.com +diamondback"
This is a very powerful way to filter out a lot of garbage, if you know the information you are seeking is at a specific site. I use it a lot just to search Head-Fi, for example - it works better than using Head-Fi's built-in Search tool.
That search lead me to this page:
http://www.audioquest.com/archives/interconnects/analog_interconnects/diamonback.html
It's in the "Archive" section of Audioquest's site - revealing that the Diamondback has apparently been discontinued.
I also found this (old) PDF on the Diamondback:
http://www.audioquest.com/pdfs/analog_interconnects/diamonback.pdf
Studying and comparing the following September 30 2015 PDF to the older Diamondback PDF (above)...
http://www.audioquest.com/wp-content/uploads/2015/10/AQ_PB_US-Retail_15-09-30.pdf
... check out what I've learned:
In their current line-up, the least expensive RCA interconnects (with prices for 0.6m lengths) are the
Tower ($23), Evergreen($32),
Golden Gate ($65), and
Big Sur ($97), but the PDF makes it easy to compare their features.
These first four interconnects all have Foamed Polyethylene as the dielectric insulator and Metal-Layer Noise Dissipation System (NDS).
Going further up in price, we have the
Sydney ($155) and
Victoria ($265),
which both have Polyethylene Air Tube dielectrics and Carbon-Based 3-Layer Noise-Dissipation System (NDS)
All six of the above, currently produced interconnects, have this geometry:
Asymmetrical Double-Balanced (Lower Impedance on Ground, Same Quality + & – Conductors)
The
Golden Gate ($65) and better cables have these conductors:
Solid Perfect-Surface Copper (PSC)
But again, only the
Sydney ($155) and
Victoria ($265) have
Polyethylene Air Tube dielectrics and and Carbon-Based 3-Layer Noise-Dissipation System (NDS).
And lastly, only the
Sydney ($155) and Victoria ($265) have
Cold-welded silver-plated connectors instead of
Cold-welded gold-plated connectors, as seen in the less expensive cables.
The only distinction between the the
Sydney ($155) and
Victoria ($265) is that the latter has Audioquest's 72V DBS feature.
Guess what! The discontinued
Diamondback ($70) is
almost identical to the
Sydney ($155). They both have the following features:
Solid Perfect-Surface Copper (PSC)
Polyethylene Air Tube dielectrics
Asymmetrical Double-Balanced (Lower Impedance on Ground, Same Quality + & – Conductors)
Cold-welded silver-plated connectors
But the
Sydney ($155) offers two improvements:
1) It uses
purple copper (better?) in its connectors instead of
red copper.
2) It uses the
Carbon-Based 3-Layer Noise-Dissipation System (NDS) - Foil / Carbon-synthetic / Foil - instead of the Diamondback's
Foil / Mylar / Foil shield.
So, even though the 0.5m
Diamondback appears to be discontinued - judging by its absence at their web site, it can still be purchased new at Amazon for
$70.00 + $5.99 shipping:
http://www.amazon.com/AudioQuest-Diamondback-audio-cable-stereo/dp/B0006DPOKC
But the currently manufactured 0.6m
Sydney sells for
$154.75 at Amazon!:
http://www.amazon.com/Audioquest-SYD0-6R-AUDIOQUEST-SYDNEY-RCA-TO-RCA/dp/B005ZBSB5A
And that's the price I found for the
Sydney, everywhere - which is full retail, per the 2015 PDF.
Decisions, decisions....
Should we pay $70.00 for a brand new Diamondback or $154.75 for the Sydney, which distinguishes itself with
purple copper instead of
red copper silver-plated connectors and
foil / carbon / foil shields instead of
foil / mylar / foil shields?
Gee, this was really tough. I thought about it for awhile, like... maybe five seconds!
I ordered the Diamondback and I'm really pleased with how it sounds relative to the following, equally affordable (or more so) RCA interconnects that are in my current inventory:
Audioquest Golden Gate RCA
Anti-Cables Level 1 RCA
Emotiva RCA
The
Anti-Cables Level 1 ($100) was my favorite RCA interconnect prior to getting the
Audioquest Diamondback.
At this writing, they are currently available for 50% off their regular price of $100 for a 0.5m pair:
http://anticables.com/interconnects...ic-Series-RCA-Analog-Interconnects/p/30770083
Anti-Cables uses a very thin but hard coating on the two conductors to act as a dielectric (to prevent shorts), where the conductors of the
Diamondback (and
Sydney) are inside polyethylene "Air Tubes" - with a similar, perhaps less effective strategy for avoiding issues associated with using foam dielectrics, as do most cables. One has to wonder, though, if the hard coating used by
Anti-Cables will eventually wear thin at points where the center conductor rubs against the outer helical conductor.
Another difference is that the
Anti-Cables Level 1 has no shielding whatsoever. Some people believe that foil shields can cause problems, even when not used as one of the signal conductors, so one could argue there is merit in not having either a substantial dielectric or a shield (a la
Anti-Cables), but Audioquest combats this problem by shielding the shield, so to speak. Both the
Diamondback ($70) and the very similar
Sydney ($155) use 3-layer shielding, with Foil-Mylar-Foil or Foil-Carbon-Foil, respectively. Audioquest's more expensive cables include up to six-layer and even 8-layer alternating carbon and foil shields.
Read more about the Audioquest NDS system here:
http://www.audioquest.com/resource_tools/LearningMods/NoiseDis.pdf
I can't say for sure if it's the 3-Layer shielding offered by the
Diamondback or some other aspect of its design that gives it a lower noise floor than the unshielded
Anti-Cables Level 1, but it's a distinct improvement, allowing me to hear more of those low-level signals that lie closest to (and hopefully never beneath) the noise floor - providing lots of information that helps to define timbre, soundstage, and imaging - making good, clean recordings sound more natural and realistic.
There's something else I'm hearing with the
Diamondback vs. the
Anti-Cables, but I'm unable to put my finger on it other than to say that listening to a lot of music with it, I just find it to be better overall, in many ways. Going back to the
Anti-Cables after a few hours of listening to the
Diamondback is all it takes to know I'm happier with the Diamondback. It might be expectation bias interfering with my already subjective objectivity (is there such a thing?), but the lowered noise floor is a distinction I can detect with certainty and I'd be very happy with the
Diamondback for that alone.
The
Emotiva and
Audioquest Golden Gate aren't even in the running, but I would put the
Emotiva ahead of the
Golden Gate.
I tested the four RCA interconnects using my primary desktop rig:
iPad 3 > CCK > Entreq Discovery USB cable (with drain wire connected to mains ground) > UpTone Audio USB Regen (powered by a 9V battery pack) > USB 3 module (Anamero designed) of a Metrum Acoustics Octave MkII NOS DAC >
RCA Interconnect > Metrum Acoustics Aurix > HD 800.
Only my DAC and amp are powered by 110V AC, with my source (iPad 3), USB Regen, and USB 3 module all running on battery power, but I've gone to considerable lengths to reduce any common-mode and normal-mode noise coming in on the mains, as well as preventing any "backwash" of noise from the DAC back onto the mains where the amp might pick it up - using a cascade of isolation transformers, as shown in this (generic) graphic I created:
[This graphic was updated on 30 Sept 2017]
My final configuration of affordable grounded-neutral and floating-neutral isolation transformers, fed by an equally affordable voltage regulator, is the result of several weeks of testing at my
audio workbench dining table. I'm crazy about eliminating and or reducing noise, so that my HD800 can hear only what they're supposed to hear.
The discontinued
Audioquest Diamondback (replaced by the
Sydney) has pushed my system a little closer to that ceiling it seems we can never reach.
Mike