INDUSTRIAL VALVE AUDIO
INTERCONNECTS
Copyright 2005-2011 Industrial Valve Audio
All Rights Reserved.
-MIL SPEC CABLES
-CRYOGENIC PULSE ANNEALED
-SUPERIOR SHIELDING
-HAND ASSEMBLED
-ALL USA COMPONENTS
-LIFETIME WARRANTY

There are thousands of brands of interconnects out there; some good, some bad, a few really great, and just about all are overpriced and marketed on very hazy Voodoo science and techno-gimmickry.

You will notice that in the following paragraphs, I will not once mention how my interconnects sound.  I will tell you the lengths I go through to deliver a quality product that delivers a very well shielded and sonically neutral signal conduit for your music. I will provide you with honest test data and manufacturing specifications, but how they sound is for you to judge.
I provide an iron-clad warranty for you to try my interconnects on your equipment for seven days absolutely risk free.  If for any reason they don't meet your standards, send them back for a full refund.  No one can judge sound quality better than you, the customer, so I will leave it to you to decide if the sound is something you like.  If not, send them back for a full refund with no hurt feelings and absolutely no questions asked. Of course I also provide a lifetime warranty for replacement or repair on these cables - just be sure to retain your original 'hangar' tag and serial number.

With that out of the way, Let us start with where this all began:

The heart of my interconnects is really the cable.  The cryogenic processing that I perform is not a new development, however I am quite sure this is the only application outside of a handful of aerospace programs that it has been used.  Here is the story behind it and how I came to build audio interconnects:
Cryogenic Pulse Annealing was discovered by accident in the 1980's at Martin Marietta as part of the Strategic Defense Initiative, A.K.A. President Reagan's 'Star Wars' Program.  At the time engineers were experimenting with cryogenic superconductors for laser power supplies.  It was noticed that certain silver plated copper cables had both their DC resistance and AC impedance drastically and permanently reduced after firing high current pulses through them at cryogenic temperatures.  This discovery was initially a nuisance, as it skewed pre and post test cable measurements, in-validating some test results.  Research was performed regarding this phenomenon, and while some of the reduction in resistance and impedance could be attributed to annealing, the majority of the change could not be explained.  The working theory proposed was that under high current conditions in cryogenic environments, impurities in the silver plating (tramp elements) migrated out of the silver and into the copper core. This left an ultra pure annealed silver coating that gave excellent skin conduction.  Testing under the same conditions using pure silver wire did not exhibit comparable reductions in resistance and impedance, which reinforced the suspicions that cross barrier diffusion into the copper core was behind the changes.   At that point the program switched to all silver wire for stability, and the book was closed on the conductivity investigations.  Most everyone involved quickly forgot about this small testing glitch.  The figure below is a graphic representation of what is thought to happen in this process.  Picture the copper core as a sponge of sorts that absorbs the minute impurities from the silver conductor under the right conduction conditions.

Somewhere in the rat's nest on the far left of the above photo, some of the identical cable used in my interconnects gave final fuzing and guidance data to nuclear bombs carried by the B-1B Lancer.
Same Cable, this time configured on a Spacecraft. This particular Satellite is currently in operation in the Van Allen Radiation Belts - A much worse environment than your listening room.
CABLE PROCESSING

Cryogenic pulse annealing and aging ?!?  Isn't it just Voodoo Science? Marketing BS?
No, and No.  In its simplest terms it involves cooling and stabilizing the cable at cryogenic temperatures in a liquid nitrogen bath, and then hitting it with a high current DC pulse.  Any micro-cracks (metallurgists would call them crystalline lattice dislocations) imparted into the conductor and shield wires during fabrication are annealed back to a homogenous state, and the overall conduction of both the conductor and shield are improved.  At the same time, any impurities in the heavy silver plating migrate out of the silver and into the copper core via solid state diffusion. This leaves an ultra pure annealed silver coating that gives excellent skin conduction.       The pulse current and duration is carefully controlled to prevent melting or welding of the individual wire strands.  The pulse is repeated at regular intervals until the measured resistance of both the conductor and shield stop decreasing and give three consecutive stable readings between pulses.  Once the resistance is stabilized, the cable is allowed to return to room temperature over several hours, and then a low level AC current is passed thru both the conductors and shield to warm and artificially age the cable over a 24 hour period.  The finished product is sonically neutral, and will not drift or change conduction properties over time or with use. 

SHIELD GROUNDING:

The best signal shielding is achieved when the signal and ground / return for the signal conductors are completely isolated from the shield ground.  Of course, this is only possible if the equipment at both ends of the cable maintain this separation.  Military Avionics and high end audio products maintain a chassis and shield ground separate from the electronics ground plane.  Coupling between the chassis ground (often referred to as a 'dirty' ground - with good reason) and the electronics ground plane are isolated either by capacitors or transformers.  This configuration allows the dirty chassis ground to absorb and attenuate unwanted RF energy, keeping the electronics ground separate and electrically clean.  My KV01 interconnects support this configuration with the shield being isolated from the signal leads, and separately terminated to a ground strap.  For systems that have a shared or common ground between the electronics and chassis, my KV02 interconnects should be used, which have the shield terminated to the signal return at the down-signal end of the connector.  

CONNECTORS:

I have always been a fan of Switchcraft connectors; they are solid, easy to work with, and are still made right here in the USA.   If you have a particular favorite, I would be happy to use that brand on your interconnect. Each interconnect can be custom made to order to length and with a variety of connector brands and types - contact me with your needs. 

SOLDER:

I use Kester Ag2Sn62Pb36 #66/44 silver bearing solder exclusively.  Nothing else comes close for conduction, surface wetting, flux action and durability.

STRAIN RELIEF / POTTING:

Each finished interconnect is injected at the connector assemblies with 3M 2216 B/A compliant epoxy to provide strain relief to both the solder and mechanical joints, and to provide environmental protection.  Each cable assembly is proof tested to 200 lbs. at each harness to connector joint. 

TESTING:

Test Data from EM (Electro-Magnetic) conduction and susceptibility testing is presented below.  The test configuration is also shown below.  I was able to call in a few, no make that a lot, no make that ALL my favors from a certain test lab (who demanded anonymity and who will deny any culpability) to run a few conducted emission tests.   Both the signal generator and data logger are isolated from the EM environment inside Faraday cages. The data logger had two recording channels available, so I borrowed the most expensive interconnect that I could find on short notice, in this case an AudioQuest King Cobra, to test concurrently with my interconnects.  The co-worker who loaned them to me was proud to point out that they cost him over $500 for the pair. 

The signal generator was configured to produce a simple 1Khz sine wave output into both channels at 1.228V against a 600 ohm terminal load (+4 dBu).  The data logger was fed both the pure signal from the signal generator, routed and shielded thru a heavy copper and lead via, as well as the resultant signal as passed through the interconnect cable.  The pure and conducted signals were then subtracted from each other, leaving only the EM noise and distortion. 
The Test Lab Setup. The EM hash generator is the big stick antenna on the right.
TEST RESULTS:

A baseline run with no background EM environment is shown in figure 1.  Blue is the IVA KV01 Interconnect, Pink is the AudioQuest King Cobra.  In this condition, both conductors are passing clean signal with no EM pickup.
FIGURE 1.  Clean EM Environment
Now things get interesting:

Figure 2 is with the environmental simulator throwing a standard 'brown' hash - a wide spectral range of EM radiation, with a spectral density proportional to 1/f^2, which concentrates energy at low frequencies.  This environment is routinely used to simulate discrete EM events, such as electrical switching, motor commutation, power line inductance, and transformer noise.  The blue response is the IVA KVO1 Interconnect, and the pink response is the Audioquest King Cobra.  Note that the time and range scales are the same for both channels.  This indicates the King Cobra cable is picking up and injecting the EM noise into the signal path.  The IVA K01 is essentially silent and providing excellent noise rejection.

FIGURE 2.  Brown EM Environment
BLUE: KV01  MAGENTA: AUDIOQUEST KING COBRA
Figure 3 is the same test repeated with 'white' hash - representative of mid to high frequency EM emissions like microwaves, computer monitors, and of course, radar.  The King Cobra is even more active in this region, while the IVA KV01 is still essentially silent.
Figures 5, 6 and 7 are repeated runs of the previous three test conditions, but with my KV02 cable substituted in place of the KV01.  Although the shielding on the KV02 type interconnect is slightly less effective than the KV01 and its fully isolated shield, the KV02 still provides excellent noise rejection in very harsh EM environments.
Figure 4 is the dreaded 212 Hz square wave cell phone 'handshake' signal that gives that annoying blipping sound on your computer monitor speakers or over your radio whenever your cell phone checks in with a nearby cell site.  Again the King Cobra cable is quite active with this signal, while the KV01 ignores it.
FIGURE 4.  Cell Phone 'Handshake' Signal
           212 Hz Square Wave
           BLUE: KV01
           MAGENTA: AUDIOQUEST KING COBRA
FIGURE 3.  White EM Environment
BLUE: KV01  MAGENTA: AUDIOQUEST KING COBRA
FIGURE 5.  Brown EM Environment
BLUE: KV02  MAGENTA: AUDIOQUEST KING COBRA
FIGURE 6.  White EM Environment
BLUE: KV02  MAGENTA: AUDIOQUEST KING COBRA
FIGURE 7.  Cell Phone 'Handshake' Signal
           212 Hz Square Wave
           BLUE: KV02
           MAGENTA: AUDIOQUEST KING COBRA
As for my friend who loaned me the tester Audioquest cables; things ended well for him as well.  He sold the Cobras, bought a pair of my KV01s, and now he has better sound and money in his pocket to boot.

KV01 OR KV02 INTERCONNECT ORDERING:

Each pair is generally made to order, but when I do batch builds, I often do a few extra pairs.  Interconnects can be built to order to match your equipment at no extra charge.  Generally no deposit is required for standard lengths and input device impedances.  To order, simply send me the following information:  Your name, email address, finished cable length (in meters), driven device input impedance (if known), and interconnect variant (KV01 or KV02).

Once I have your order information, I will provide you with an estimate of when I anticipate your interconnects will be complete and ready to ship.  Orders are filled in the order they are received.  When your interconnects are complete, I will send you an invoice via paypal. The cables will ship the same day as paid.  If I do not hear from you within seven days of invoice, I will assume you are no longer interested in completing the order, and will offer your interconnects to the next person in line that ordered that same cable configuration.  I will continue to accept orders until the cable stock on hand is depleted, at which point I will place names on a waitlist pending the next delivery of cable.  Current lead time is approximately 3-5 days on these interconnects.

Pricing is as follows:
KV01 or KV02 interconnects, total length of 1 meter or less: $88 / pair.  Each additional meter, or fraction thereof, +$50.  Maximum available length: 2 meters.
Pricing includes shipping via USPS Priority Mail for both domestic and international orders.
Options:  Alternate RCA connectors (WBT, Cardas, etc.):  $20 discount for unused connectors; customer to provide alternate connectors.  No returns on alternate connector configurations.



CUSTOMER COMMENTS:


"Have been using these recently acquired 1/2m cables in my dedicated headphone set-up. They replaced some 1 1/2m silver cables that performed very well but were too long.  These perform better.  In my system, these cables disappear. My immediate impression is that I hear more color separation and better detail particularly in the top end.
Why?

Back in the days of 35mm film cameras, when dinosaurs and I roamed the earth, I always shot with Contax cameras using  Zeiss T* lenses. 
These lenses had a remarkable ability to transmit light,  yielding images that were very sharp and  gave extremely high color contrast.  That is,  very slight changes is color tone were faithfully reproduced.

Your cables remind me of that.

Sound color is richly transmitted because the cable are so quiet." -Unmesh, New York

"Fantastic cables!  I love the neutral sound and absence of coloration. I REALLY like the fact that I can run them haphazard as I want without any noise pickup or room interaction."   - Ron K., Fairbanks Alaska

"I am very satisfied with these interconnects.  They do what you say.  They are very quiet and not bright like I expected.  I did notice some break-in effects over several hours of run time.  They keep sounding better the longer I listen.  Thank you for a fine product and quick shipping - I will definitely be buying some more of these as I expand my electronics collection."  - Jeff S., Wichita Kansas 

"Thank you very much for the prompt shipping.  I have just started to enjoy these fine cables, and can say that they are already easily the best that I have heard.  I am very glad that I found your site, and will keep you informed as they break-in. I'm sure I am only at the tip of the iceberg for their true capability at only 20 hours of run time."
-        Dan G., Broomfield Colorado

"I am very satisfied with the absolute industrial construction and wonderfully clean sound of these RCAs. None better in my book. I would have paid a lot more for this sound!"
-        Ilio V., Rome

"I was very skeptical at first as to whether these cables could deliver as hyped at the price advertised.  Since you offered the free trial I decided what the heck, why not.  I am so glad that I did.  I have been a rabid audiophile for most of my adult life, and these kick the pants off other cables costing 3X as much!  The sound is very clean and detailed.  Holographic but not too bright.  I can hear faint nuances in the music using the KV01s that are just plain missing with my Cardas sets.  I am also ordering one of your EF86 preamps soon.  If they both have the synergy that I anticipate, I may finally settle down and quit playing the field!"
-        Steve L.,  New York

"Smooth as silk.'
-        Oscar S.,  Sunnyvale, CA 


Fast forward 10 years to another program where extremely long cable runs on a spacecraft were degrading high frequency RF analog signal integrity.  By chance, we were using the same cable that had been involved with the SDI tests, and someone that had worked that program remembered something of the testing glitches. We were able to find a hard copy of the original test report, and based off the original testing, we were able to put together a small scale processing area in some excess lab space to experiment with this cryogenic annealing.  After some trial and error, we were able to develop a process that consistently produced marked reductions in cable resistance/impedance.  A formal procedure specifying temperature, voltage, current and pulse duration(s) was issued with the official title 'Cryogenic Pulse Annealing with Suspected Inter-metallic Elemental Diffusion'.  This process was performed on the problem flight harness, which solved the analog signal integrity problems.  Everyone involved got a nice award certificate and a quick photo-op with the Unit Vice President.   After that, the process was promptly shelved and forgotten again.
Fast forward another 10 years.  I was in the process of moving my office, and in the bottom of one my drawers I found some pieces of cable processed during the original testing.  I was also in need of some longer interconnects for the stereo in my new and *larger* office.  Serendipity struck, and I used the cable to fabricate a pair if RCA patch cords.  I terminated and grounded the jacket shield separately from the signal conductors in the hope that it would provide improved noise shielding - important because my new office was directly behind the RF test lab.  Turns out I had a real winner - both for sound and shielding.  These cables became the progenitor to the KV01 that is still the bread and butter of my business today.  I built another two pairs for my home system, sold one to a co-worker (see below for the details on that…), and with the last 4 meters of cable that I had left, I built two more pairs and sold them on ebay.
With all positive reviews coming back to confirm what I was hearing from the cables, in July of 2008 I decided to take the plunge to start building and selling them in earnest.  I invested in the same equipment previously used for the cryogenic annealing, and duplicated the original lab setup in my shop. 
My philosophy then and now is simple - everything is built to the same processes and with the same materials as used for military radiation hardened spacecraft wiring harnesses.  If it is good enough to transmit high speed encrypted data to earth from a Classified National Asset in orbiting in outer space, it is certainly good enough to link the pieces of your stereo system together in your living room.  'Mil-Spec Gear for your Ears' isn't just a catchy motto - it's the truth.
The KV01 variant today remains unchanged from the original pair that still resides in my office.  The KV02 has had only one minor modification since its original release in that  KV02 cables built after May of 2010 have had a small ferrite core added to the shield termination inside the backshell to improve rf rejection.  If you are the owner of any KV02s built to the prior specification, please email me for a return and free upgrade to the new version.

Latest Developments!

I am very happy to announce the release of the new KVX interconnect family.  These new cables are the synthesis of two years of hard work to refine the original cryogenic annealing process while adding a true Litz conductor configuration.
While the signal leads inside both the KV01 and KV02 cables are both optimized for skin conduction, they are not true Litz conductors due to the fact that the individual wire strands that make up the spiral wound cable conductor are not insulated from each other.  With the KVX, each individual wire strand is electrically isolated from the others in the cable core, forming a true Litz wire configuration whose performance is further enhanced by the cryogenic annealing and diffusion process.   The KVX is only available in the classic three wire Litz braid.  If you are looking for a truly neutral cable that will precisely replicate the original signal with no artifacts or coloration, this is it.  I'm not going to go into flowery language or techno-babble to try and sell these on you.  Instead I am going to offer up this:  Buy a pair.  Compare them against whatever you currently are using for a month.  If the KVX doesn't knock the pants off of whatever you put them up against, send them back for a full refund.  No hype; Just simple put-up or shut-up.  I have been offering this same guarantee with the KV01 and KV02 family of interconnects for over three years and not one pair has ever been returned.  The KV01 and KV02 are great.  The KVX is even better.  

I have optimized the cryo anneal process for the new Litz wire conductors, and can now process individual conductors up to 2 meters in length.  Thank you to everyone who provided inputs on sound merit for the test batches!  Ordering and technical information is here:
With the KVX, I purchased a mill run of Litz wire built to my specification.  This cable has a Teflon (Tefzel) jacket, and each individual heavy silver plated copper wire strand is individually lacquered and electrically isolated from the others in the cable core. This forms a true Litz wire configuration whose performance is further enhanced by my cryogenic annealing and diffusion process.  Cable capacitance is minimized by an exclusive woven braid utilizing a 'null' cable in addition to the signal and ground leads.  The completed cable capacitance is an unheard of low - less than 10 pF / foot.  Tested transmission bandwidth from DC to 1MHz is within 0.5 dB and phase error (individually tested and documented with every cable) is less than 0.2 degrees over that same range. If you are looking for a truly neutral cable that will precisely replicate the original signal with no artifacts or coloration, this is it.  I'm not going to go into flowery language or techno-babble to try and sell these on you.  Instead I am going to offer up this:  Buy a pair.  Compare them against whatever you currently are using for a month.  If the KVX doesn't knock the pants off of whatever you put them up against, send them back for a full refund.  No hype; Just simple put-up or shut-up.  I have been offering this same guarantee with the KV01 and KV02 family of interconnects for over three years and not one pair has ever been returned.  The KV01 and KV02 are great.  The KVX is even better.  
I still build each and every one of these from start to finish by myself, and have no plans to change that.  This year I have enough Litz cable on hand to build ~45-50 pairs.  Additional cable from Draka France built to my same specification is on order, but due to factory backlog, it will very likely not be available until the middle of next year. 

KVX ORDERING:

I had been selling direct off of this website, but the backlog kept growing, and growing and growing... To the point I couldn't keep up.  So, I quit accepting new orders until I had caught up, and now am selling exclusively on eBay.  I generally have time to build one or two pairs a week, and I list them as I finish them.  All listings start at 99 cents, and end up wherever bidding takes it.  Perfect free market at work.  Listings are here:





KV01 & KV02 Interonnects:

I use M27500-20SC2S23 cable exclusively for the KV01 and KV02 cables.  This is a mil-spec cable with a twisted pair of 20AWG conductors under a braided shield and overwrap.  The conductors and shield are both silver plated high strength (read that as alloyed) copper. All conductor insulation and shielding are fully cross-linked ETFE Teflon. Cable built to this specification from the factory is fully qualified for use on military aircraft and spacecraft.  Before you say things like "But I've heard silver plated copper sounds dull…", or "Alloyed copper sucks as an audio conductor", consider this:

1)This very same cable is used to transmit the final fuzing and target parameters to the nuclear bomb warheads on both the B-1B Lancer and the B-52 moments before weapon release.  This signal has to arrive complete and un-corrupted through the worst Electromagnetic Hash Imaginable: Nearby nuclear detonation EMP (electromagnetic pulse) events and High Power Soviet Radar Tracking and Jamming Signals.  If it can deliver a coherent extremely high data rate signal through that type of toxic electromagnetic smog, it can certainly shield against something puny like your microwave oven, computer monitor or electric dryer.

2)This cable is also used for high data rate signal coupling on US Imaging satellites that are considered to be National Assets (read that as insanely expensive, and absolutely bombproof).  When engineers had carte blanche to pick any cable based solely on performance and operating life, and where price was not even a consideration, this is the cable that was picked time and time again.

3)This cable with additional processing (cryogenic pulse annealing and aging) is used to conduct extremely weak analog signals from detectors to amplifiers on spacecraft operating within the Van Allen Radiation belts.  Cable processed to these same specifications is what I use in my interconnect cablage.


Current listings on Ebay