MEASUREMENTS: AKG Q701 "Quincy Jones Signature" (2012) & AKG K260 (vintage 1987-1988). And recent interviews with audiophile cable/power people [Shunyata / AudioQuest].

For today's post, let's have a listen and look at the two AKG headphone models above separated by about 25 years in age. On the left we have the AKG Q701 "Quincy Jones" Signature Reference-Class Premium Headphone which was released in 2011. I bought this one (I preferred the black rather than some of the funky colors like neon green) in late 2012.

On the right, we have a rather uncommon AKG K260 - first edition released in 1987-1988, borrowed from my friend linnrd locally. A later versions of this headphone was relabeled with the "Professional" name attached. There's also a Philips version from back in the day using AKG as OEM. This particular one here is used but still in good condition which I cleaned up a bit before more critical listening and measurements.

Notice the "AKG look" with the leather or faux-leather headbands and the thin plastic/metal semicircular arches up top.

MEASUREMENTS: Do power cables make a difference with audio amplifiers?

Alright guys, as you probably know, here at the Musings, I'm not in general a "cable believer". This doesn't mean I'm a "cable denier", after all, I need them in order to hear something from the system :-). Over the years I have written about silly cable claims, and here's the summary post looking at all the cable varieties I've measured (I will of course include this article in there as well).

With measurements dating back to 2013, I have neither heard nor seen any evidence to compel me to recant my opinions on this matter. Furthermore, I have not seen any new articles exploring the topic with any kind of depth in the audiophile press. No audio cable company has produced material demonstrating a believable, sonic benefits for their $$$$ products. Despite countless ads in magazines, I see a lack of accountability from the mainstream press to investigate; it's really just about maintaining the status quo and promoting sales of high-margin luxury products as far as I can tell. No magazine wants to purposely publish stuff that results in loss of advertising revenue from a whole segment of products, right?

Up to now, the power cable measurements I've published have been with low-power devices (ie. measuring DAC output quality with different power cables), but what happens with higher current demands, when the device needs >100W from the wall socket? In the last few months, since I've been working on amplifier measurements, I have had the opportunity to try measuring power amplifier output using different power cables.

MEASUREMENTS: Apple's Lightning to 3.5mm Headphone Adaptor [MMX62] (CES 2018 Creative Super X-Fi audio, and A/C cable "proof"?)

Ludicrous combination of iPhone 6, Lightning to 3.5mm adapter, and Sennheiser HD800 :-).

Well, as you likely already know, since the iPhone 7, Apple has removed the 3.5mm headphone port from their phone devices. Ostensibly, the rationale being that this would allow more space in the device for other goodies to enhance the feature set of the phones.

In place of the missing headphone port, Apple has included the "Lightning to 3.5mm Headphone Jack Adapter" with their phones. I've been wanting to have a look/listen to how well this little dongle thing performed for awhile but since I'm an Android guy and nobody close to me upgraded their iPhone when the 7 came our, I just remained patient. Well, over the holiday season my sister-in-law upgraded to an iPhone 8, so I finally got a hold of one of these Lightning-to-analogue out dongles to test out at my leisure :-).

MEASUREMENTS: Power Cable Redux. The Synergistic Research Tesla T2 SE, T3 SE and PowerCell 4.

As promised over the last months, I've been wanting to borrow some expensive cables to measure to see for myself if I can both objectively and subjectively experience a difference. I've measured power cables before with my ASUS Essence One DAC's output but it just so happened that recently a friend decided to "go deep" into the world of audiophilia and purchased a little "family" of Synergistic power cables to try out:

What we're looking at here is a "tree" of Synergistic gear :-). Plugged into the wall is a "Tesla T3 SE" cable connected to a "PowerCell 4" (basically functions as a 4-outlet power bar). Coming out of the PowerCell on top are 2 "Tesla T2 SE" cables and an Audience power cable (not evaluated here). The blue lights come from the "Enigma Bullets" which I'll address a little later. My friend has been listening with them for >6 months so there's no issue with new cable "break-in".

As has been expressed by others, it's hard to make a case for power cords... The AC in our homes are connected through tens/hundreds of miles of cabling of various gauge. Within one's abode, it's interconnected with multiple outlets (unless of course you hire an electrician for a dedicated line) usually through 14AWG copper wires for most 15A circuit breakers here in Canada. Could the last few feet be significant?! Does running fancy cables like those above really improve sound quality? Here's a chance to have a look and listen...

I. A Look at the Synergistic Tesla T2 SE (5'), T3 SE (5'), and PowerCell 4

For the purpose of these measurements, I wanted to keep it convenient for my friend - the way it's configured as already attached to the Oppo player:
Oppo BDP-105 <-- Tesla T2 SE <-- PowerCell 4 <-- Tesla T3 SE <-- Wall outlet

I'll spend some time talking about the T2 SE since it's the cable directly connected to the Oppo. You can have a look at the manufacturer's information at their website if unfamiliar with this cable. Although not the "top of the line" AC cord, this unit has most of the "headline features" which supposedly provides benefits. It's got some kind of silver & copper conductor construction, "Tricon" and "T2" (?) geometry, high quality "G 07" IEC plugs... Then there's the "Quantum Tunneling" - some kind of 2 megaV pulsatile "treatment" that transforms "the entire cable at a molecular level" (what molecule(s) they did not say...). Check out some more pictures here.

Finally, we have the well advertised "Active Shielding". The claim here seems to be that using an electrically active (DC current) shield improves noise level and some how "greater frequency extension from top to bottom." We are of course not graced with any charts/graphs/details as to how this was determined.

To make things even more "enigmatic", we have these "Enigma Bullets" a.k.a. "Active Shielding Modules" capable of "tuning" the sound! They screw into the pigtails hanging off the male ends of the power cables. Silver = "open and airy", Black = "warm and rich", Grey = kinda in between. Hopefully the pictures below clarify the description:

Despite the huge calibre of the T2 SE cable, it actually feels rather hollow so it's hard to tell what wire gauge is being used inside.

Here they are, the "Bullets":

Cute, solid-feeling metal pieces with an electrical connector on one end and a little LED (the blue light shown in the 1st picture) on the other. They get warm plugged in to the DC source so I whipped out the multimeter and got 1400-ohms resistance for the black one, and curiously 1200-ohms for BOTH the silver and gray ones - not sure if this is supposed to be the case.

The "DC power" end of the "Active Shielding" is connected to what basically is a wallwart ("Mini Power Coupler") - here's a picture of them (2 for T2 SE, 1 for T3 SE) connected to the power bar:

Notice the $399 MSRP Synergistic "Quantum Line Strip" QLS-6 - power bar, no surge suppression - also "Quantum Tunneled"!

Of interest, you'll notice that one of the wallwarts had a sticker that fell off over time! Here's a close up of the label underneath:

A basic wall plug AC adaptor, 24V 300mA switching power supply you can order bulk from ENG Electric in China or Taiwan. Unless I'm mistaken, asking price for one of these is $125 (here)!

Here's the manufacturer's page on the PowerCell 4. It functions as a 4-outlet power bar. I don't think there's any surge suppression on it. It felt surprisingly light weight to me. I have no idea what they mean by a "magnetic cell" or what benefit that affords (?are there magnets in there?). Also, the comment about "The PowerCell 4 also improves picture quality on any display, with darker black levels, better color saturation and a more 3 dimensional picture, simply amazing" should be objectively assessable.

Finally, between the wall outlet and PowerCell 4 is the hefty Tesla T3 SE power cable. Again, here's the manufacturer information page. Looks to me that the main difference is the higher number of conductors (ie. thicker overall effective wire gauge) compared to the T2 SE above. You can read more about this PowerCell & T3 SE combination in this subjective review.

T3 SE cable plugged into wall. Notice its own lit "Enigma Bullet" and you can see the "Active Shielding" winding wrapped around the main power cable.

I could not find a price list all in one place... But the MSRP is something like this as of January 2014:
- Tesla T2 SE cable - $650/5ft (here)
- PowerCell 4 (North American) - $1,250 (here)
- Tesla T3 SE cable - $900/5ft (here)
----- Total MSRP for the set = $2800 USD

 

II. The Test

My friend lives in a multilevel condo and I figured that if indeed an expensive AC cable system is capable of cleaning up the noise coming through the outlet, then this is the kind of environment to demonstrate an advantage!

Of course, the comparison must be to a generic IEC cable, but lets make the generic AC cord even more disadvantaged - I'm going to add a 12' length of inexpensive extension cord to it. Measurements will be taken off the RCA output from an Oppo BDP-105 which he uses (the Oppo is an excellent USB DAC based on previous tests a year ago). This also gives me an opportunity to show a few measurements beyond my usual ASUS Essence One / Transporter / TEAC UD-501 trio of DACs.

Here then are your test "subjects":

A. Synergistic Research Tesla T2 SE to PowerCell 4 to Tesla T3 SE plugged into the condo wall plug:

B. Generic 6' 18AWG IEC AC cable I got 'free' in the box with something (black) + Generic 12' extension cable (white) into condo wall plug:

Test Setup:
Win 8.1 i5 Ultrabook --> shielded USB --> Oppo BDP-105 (powered with either A or B above into outlet) --> shielded (Tributaries) RCA --> EMU 0404USB --> shielded USB --> Win8 AMD X4 measurement laptop

- Newest Oppo USB driver (1.61)
- Latest RightMark Audio Analyzer (6.3.0)

 

III. Results

As usual, I'll measure at 16/44 to make sure the results cover standard CD-quality output. Then I measured 24/96 to get an idea of "high-res" performance. The tests were run under 3 conditions: Synergistic system without Active Shielding (wallwarts unplugged), Synergistic system with Active Shielding using Gray "Bullets", and finally the generic IEC cable + extender. (Note that in the labels I used "T2SE" but in fact the whole Synergistic chain was measured including PowerCell 4 and T3SE.)

16/44 (standard CD resolution):

Frequency Response

Noise Level

IMD + N

24/96 (high-resolution):

Frequency Response

Noise Level

IMD + N

As you can see... The expensive Synergistic power cords + PowerCell made absolutely no difference to the Oppo's analogue output compared to an absolutely generic power cable attached to extension cable for both standard resolution 16/44 and hi-res 24/96 test signals. Inter-test results were essentially exactly the same in all 3 conditions. No evidence here that the Active Shielding made any difference either.

For those who might wonder about jitter...

Again, no different. (Of course one cannot expect a power cable to affect jitter nor J-Test to be too anomalous through an asynchronous USB DAC.)

IV. Conclusion

Within the limits of the testing equipment - the EMU USB0404 as ADC - there is no difference using the Synergistic power cords with the Oppo BDP-105 compared to a generic 18AWG IEC power cable with extension cable in a multilevel condo building near the heart of the city.

Although the USB0404 isn't to be used professionally as test gear, as previously shown, it is a capable "measurement" device able to demonstrate very tiny effects like the -90.3dB LSB test, effect of digital filters, and slight differences between similar SPDIF digital transports; all of which I believe would be below the threshold of hearing for the vast majority of people. As such, I do believe the results above to be accurate and reflect reality when it indicates there is zero difference.

Could these fancy cables improve the sound from other devices like power amps or older technology like tube gear? I don't know... Remember though that tube equipment have much higher noise floor in general so even if this cable could lower it, the difference would likely be irrelevant. As usual, if power cables could substantially improve sound quality, why has there not been good evidence after all these years? I've often wondered why cables like these are not subjected to objective measurements like speakers, DACs, pre-amps, etc. in magazines like Stereophile using their fancy measurement devices? (Heck, many of these cables cost substantially more than good components!) Furthermore, right on Synergistic's web page, we are told that the "Active Shielding" lowers conventional parameters like noise floor and frequency response ("this closed circuit design not only improved subjective performance, but also made our cables measureably (sic) quieter, thus improving detail with greater frequency extension from top to bottom..."). So where are those measurements, and under what conditions? Peripherally, gimmicky marketing terms like "Quantum Tunneling" as it refers to the process they use really should be better explained (seriously, any time a company starts referring to Quantum-anything in the macroscopic world, it's best to be cautious). Finally, if sonic improvements can be made with a cable, did Oppo not bundle one they've tested to be optimal despite all their other engineering efforts?

Subjectively, I have heard my friend's system with the Synergistic cabling and with the generic power cable (as well as other systems with fancy cables but not to this degree of testing). To be honest, there's really not much to say subjectively with any certainty doing a tedious A/B/A trial. Do I think the Synergistics make the sound better? I'll go with the objective results and say this is most unlikely... Without a special setup, it's essentially impossible to do an accurate A/B comparison since there would be too much delay between cable switches, Oppo boot up, then start playing a song to really make any reliable comparison based on auditory memory of mental markers for high-fidelity. If audio qualitative differences were big enough, of course this could be a trivial task, but for at best tiny differences as in this case (if any), I do not believe this is possible based on research into the limitations of echoic memory. Good to see the measurements at least did not show any worsening using the exotic cables. All I can factually say is that the Oppo BDP-105 sounds great (and measurements demonstrate this high fidelity) through his system irrespective of which power cable(s)!

When it comes to power cables in my home system, my internal wiring is standard 14AWG copper and that's the "best" it's ever going to get in terms of power distribution. I don't see how passive wires can do anything for noise floor or "control resonance" or such beliefs. I'm quite happy with generic shielded 18AWG IEC cables for low power devices like the DAC, pre-amp, DSP equalizer. For higher power devices like the monoblock Emotiva XPA-1L and Onkyo AV receiver I have 16AWG shielded generic cables. I do not believe I hear a difference between the 18 and 16 gauge cables with the amps (in fact at one point I had an 18AWG cable on one monoblock and 16AWG the other and notice no stereo imbalance, noise, etc... even at high volumes) but I guess at least it makes me feel good that I did a little more to feed the neurosis :-).

As usual, please feel free to drop a link if you come across other tests on cables such as these; especially tests which have shown significant differences.

Recommendations:

- I've been listening to Eric Bibb's Blues, Ballads & Work Songs (2011) recently and I'm enjoying this Opus 3 SACD (was listening to the PCM layer on my friend's system the night of the Synergistic testing in fact). Easily accessible and great resolution!

- Mark Waldrep (aka "Dr. AIX") runs a nice blog at Real HD-Audio. Opinions and insights from a respected figure in the high-fidelity/audiophile world who clearly "keeps it real". If you haven't, I would highly recommend having a listen to some of AIX's recordings; especially in multichannel and the samplers provide a taste of his work. He posted an amusing recent anecdote on the use of a standard 75-ohm cable for digital audio at CES 2014. Also calling out the snakeoil on these "treatment" products sold through Blue Coast Records  - I wonder if they work better in PCM vs. DSD :-) (Dr. AIX's blog post). Respect.

Enjoy the music... And keep it real, folks :-).

PS: A big thanks to my friend for offering and helping with the testing - he has of course reviewed this write up for accuracy.

Addendum: For more about Synergistic Research and a DIY Synergistic Research HFT-like room treatment, check out this post in 2026.

MEASUREMENTS: Power Cables for Low Power Audio.

We are told - "everything makes a difference!"

Expensive power cables are an example of taking this principle more than likely to the extreme - well into the territory of the neurotic obsessive-compulsive. Some audiophiles claim there are very significant differences to be found by replacing standard cables like the common IEC connector varieties between the mains and one's gear. DIY plans are available on the Internet, and of course many enterprising companies have produced all kinds of cables to satiate those "believers". Like other cable claims, it's difficult to determine what scientific / engineering theory could account for these beliefs. While there could be some justification to use of heavy duty power cables for high-powered amps with dedicated circuits for example (very rare for home audio), why would someone need fancy cables for devices like DAC's or CD players where internally the AC is converted to low voltage and current DC to power the electronics? Furthermore, we all know that the electricity supplying our gear is connected by hundreds of miles of plain old non-"audiophile approved" copper cables of various diameter and quality.

In order to look for tiny differences, I'm going to try using various power cords with the ASUS Essence One DAC (note that my DAC is slightly modded with all LM4562 op-amps)... Let's see if there are any differences looking at the analogue output and changes to the J-Test jitter spectrum.

First, as usual, I had a look into my closet of cables to see what I have. Here are today's selection:

Cable A:
No nonsense generic freebie 6' cable that came with my old Antec computer power supply. Has the brand name "LINETEK" stamped on the connector.

Cable B:
Notice the green dot on the plug. That means this is a higher quality "hospital grade" cable. Also 6', but it's about 25% thicker, and twice the weight of Cable A. Strain relief is fantastic. The metal wall plug prongs are more substantial and the ground prong is solid metal instead of hollow like for Cable A. Presumably the thicker diameter indicates better shielding. I know this particular brand of cable is being used in the local hospital's ICU department. If this cable fails during use, patients could die...

Cable C:
I looked around to see what was the absolute WORST power cable I could come up with. Here it is - total 56' long. Using Cable A, I connected it to a 50' yellow outdoors cable I used over the Christmas holidays for the outdoor lights. In fact, this cable has been used for this purpose for the last 5 Christmases at least, so it's been exposed to the dirt, rain and snow. The metal prongs in fact look worn and oxidized. In fact, this is so nasty that I took a picture of it out on the deck since my wife refused to have it indoors for more than a few minutes for testing :-). I tested it connected to the DAC pretty much looking like this tangled mess. Unless you think the last 6' of generic power cable can make a difference, the "performance" of this cable should unequivocally "sound"/perform terribly.

Gear Setup:
I used a variant of the usual testing setup:
Win 8 laptop --> shielded USB --> CM6631A asynchronous USB to SPDIF --> Acoustic Research 6' TosLink --> ASUS Essence One (*connected to wall outlet by test cable*) --> 6' XLR cables --> E-MU 0404USB --> shielded USB --> Win 8 laptop

Note that I decided to use the CM6631A device for USB input and TosLink out (previously tested) instead of the native Essence One USB because I actually found less jitter this way. I noticed that the Essence One's USB input has a fair amount of low level jitter artifacts - not sure if it's a result of the CM6631 (non-A) chipset or the drivers in this configuration.

Analogue Measurements (RightMark Audio Analyzer 6.2.5, 24/96):

Summary:

Pretty much identical...  Very small differences within the error range for each "run" of the test.

Frequency Response:

Noise floor:

THD:

Stereo Crosstalk:

As you can see, there's nothing here to differentiate the analogue measurements from the DAC using the different power cables.

Jitter Analysis (Dunn J-Test - 16-bit and 24-bit variants):

Cable A - 6' generic:

Cable B - 6' Hospital Grade:

Cable C - 56' - 50' outdoors corroded prongs + 6' Cable A:

Again - no real difference folks. Not really that one expects any difference since it's unlikely that the DAC's internal timing circuitry could be affected by the AC input. Note that with the Essence One, we can actually see the 24-big jitter modulation pattern due to the very low noise floor below -140dB.

Conclusion:

As usual, I listened to the audio output using the poorest cable configuration after I ran these tests and as I ponder what to write for the blog entry. Indeed, the sound was fine.

Tonight, I was listening to the Erich Kunzel & Cincinnati Pops' rendition of Tchaikovsky's 1812 Overture (Telarc 2001, SACD digitally ripped & converted to 24/88) with the Essence One powered by the nasty 56' length to the wall socket. It sounded good. By ~14 minutes into the track, we hear a multi-textured climax with church bells, choirs, brass, percussion and of course cannons. The complex mix was reproduced very well and rendered nicely with my AKG Q701 headphones - plenty of dynamics being pumped out into the Essence One's headphone amp.

Sure, it's possible that "everything makes a difference!" As in most things in life, the wise man needs to ponder the claims a little further to divine the truth. At least when it comes to power cables, I think the wise man can comfortably walk away from such claims of audible differences and realize that a decent IEC cable is all that's needed - at least for low power devices like a DAC.

As is my usual policy, I do not bother measuring high-priced cables - partly because I don't have any at home - but these posts are not about pointing fingers at specific companies. Rather I hope the measurements and comments stimulate thought. Note that I have "heard" expensive power cables over the years so am well aware of their "performance". As usual, drop me a note if you have good evidence to show otherwise...