highend-electronics Terminators

by admin on March 26, 2009 · 18 comments

in Accessories

by Andy Fawcett

“The fates have given mankind a patient soul.” Homer, The Iliad

That karmic destiny conspires to return us to those junctures in our lives where business was left unfinished, I do not doubt. Yet I have also had cause to ponder, only partly in jest, whether we do not also possess an “audio destiny”. While browsing the Audiogon website recently, I stumbled across a company called highend-electronics (sic) selling sets of shorting plugs - the mere sight of which evoked a vivid recollection of that brief period, some 20 years ago, when the UK audio scene was gripped by a wave of enthusiasm for these devices. Indeed, several amplifier manufacturers (even semi-mainstream ones) went so far as to supply their more serious models with small, plastic-bodied shorting plugs fitted as standard equipment.

Despite being a committed tweaker at the time, somehow I never quite got round to putting a set together and trying them out. Before long there was a new fad to obsess about and, in the two decades since, I’m not sure that I’d given shorting plugs another thought. This time around, with a genuine feeling of history repeating itself, I felt duty-bound to purchase! The company also offers a “digital-terminator”, for unused S/PDIF sockets on CD players, which I chose to sample for no other reason than that it was too cheap not to. Having acted entirely on impulse, it was only some weeks later that I dropped a line to the company’s owner, Alfred Kainz, at his premises in the California desert … and realised that there was much more to this story than I’d suspected.

Firstly, though, you might be asking what shorting plugs are - and why you’d need them in your system? The theory, as best I can recount it, is pretty simple (no surprise there). Audiophiles have long been aware of the adverse effects of RFI (radio frequency interference) upon the transmission of music signals in the electrical domain – it is one reason, for instance, why the conductors in quality audio cables are typically braided together, that pattern considered effective in suppressing RFI pickup. Any unused (ie. unterminated) analogue input on your pre-, integrated or (less commonly) power amplifier can act as an aerial for RFI, facilitating its ingress into sensitive circuitry and degrading sound quality; a situation that is remedied by shorting the terminal out. This is generally the case even when the amp’s inputs are switched; only in a very few designs (some McIntosh models, for example) are unused inputs physically disconnected from the circuit, and thus stand not to benefit from shorting. While we’re talking exceptions, unused single-ended inputs on power amps must not be shorted where they are connected in parallel with the balanced inputs – this includes models from Levinson, Audio Research and Pass Labs, among others. The really important point to emphasise here is that shorting plugs must NEVER be applied to amplifier outputs – to do so incurs a high risk of destroying the output stage. I do wonder whether this vital caveat is the reason why amp makers ceased to supply shorting plugs as original equipment, rather than it being any reflection on their effectiveness.


Offered as three pairs of RCA plugs at an inclusive cost of just US$22.90, the unobservant audiophile (writer examines shoes closely and attempts to whistle …!) might be excused if he noted the quality, chrome-barrelled Neutrik phono plug with quiet satisfaction, and thought no more about it. After all, you’re only shorting out an input, right – nothing tricky about that? Well, those of an unduly sensitive or objectivist disposition may wish to sit down and take an aspirin at this point … because the humble shorting plug is about to get complex! You see, Alfred has been experimenting with these things for a good many years, and his listening tests have not only revealed significant audible differences between various types of shorting plug, but led him to insist upon a very specific (not to say esoteric) set of design criteria. Only a shielded, non-magnetic phono plug with gold-plated contact surfaces will suffice. The plug is then cryogenically treated, and the shorting connection made with a high-quality OFC wire, before being internally potted with a compound to damp resonances in the plug.

I’ve paused for dramatic effect at this point, because I encounter self-proclaimed ‘rationalists’ in online forums who would be rendered apoplectic with rage at the very suggestion that any of this stuff could make the slightest difference. They protest themselves ‘scientists’; in truth, they are nothing of the sort. Their self-righteous assertion of a doctrinaire stasis relies upon (a limited interpretation of) the theory to deny the evidence – forgetting that the scientific method demands a progression in the opposite direction, and ultimately proving nothing but the paucity of their imagination. Sorry, I’m venting … you can tell. But that’s what I find so inspiring about Alfred’s approach; he has thought to question the unquestionable and, with open mind and open ears, pursued it with a passion that both epitomises the genuine spirit of scientific enquiry, and embodies what it is that makes our hobby great.

On the other hand, none of this matters a damn if they don’t make your system sound better. After many weeks of contorting into the narrow space behind my audio rack to swap out cables it was, at least, refreshingly quick and easy to fit and remove the analog-terminators. And yes, they brought about a sonic improvement that easily surpassed my modest expectations. There was a cleaner, clearer feel to the soundstage – not really extra resolution as such, more of a ‘tidier’ presentation. While I’d anticipated that any benefits would most likely be apparent in the treble region, it was actually the bass that demonstrated an increase in focus and tautness. But where these plugs really hit home was in eliminating a mild excess of energy through my system’s upper bass/lower midrange, which tended to manifest as a generalised ‘fogginess’ and congestion on complex material. As changes go, perhaps it wasn’t wildly dramatic … but it was exactly what the system needed, and yielded a significant return in listening pleasure.


Now this one is completely new to me – both the concept and the application. The explanation for its effectiveness is somewhat different; it aims to combat not RFI but internal ‘reflections’ from unused S/PDIF in/outputs on CD players, transports and DACs, these claimed to interfere with the main output signal. It shares all of the analog-terminator’s design elements and construction, save that the shorting is achieved with a precision (0.1%) 75-ohm Vishay resistor, providing optimal termination to the S/PDIF standard. In case you’re unsure, it’s the digital transmission format that employs a standard RCA socket; so if, with your player’s analogue outputs in use, there’s still a single naked RCA socket visible on the back then keep reading! Sold individually for just $10.90, it’s not a purchase you’ll struggle to justify.

Nor, if my experience is a guide, one you’ll regret. Initially assessed in isolation, before the analog-terminators were installed, the strongest impression was that my CD player’s sound had more of an analogue feel to it; a smoother, looser, less processed character that I enjoyed for its more natural musicality. After living with my system for a couple of weeks with all of the shorting plugs applied, I removed just the digital-terminator in an attempt to verify that finding – but was now no longer hearing it the same way. Perhaps the addition of the analog-terminators was a factor, or I may simply have become inured to it, but this time I observed (in direct A/B comparisons) only a variety of more conventional sonic improvements; a harmonically richer presentation and a smoother, tighter and fuller sound, fractionally increased resolution, that sort of thing. In truth, the difference was often felt as much as heard, the sound demonstrating a subliminal sense of ease that, even without any great attempt to analyse it, simply made me glad to have the digital-terminator on board. Perhaps that’s inconclusive; but whatever resolution of the issue might have been reached through further comparative testing, there’s no guarantee that your experience would be the same, and it’s probably fair to assume that results will vary markedly between different CD players. What I can say is that the digital-terminator undoubtedly merits your attention and, hopefully, a few adventurous souls with $10 to spare will try it out and post their impressions below.


I never had any intention of writing this article. Acquiring these plugs was, in a strange and personal way, my homage to the past and I harboured no great expectation of a significant performance gain. Their low price only reinforced that presumption; as audiophiles, we are well used to paying handsomely for our pleasures. Yet the sonic benefits they have engendered in my system are out of proportion to their cost, and compel me to share my enthusiasm with you. As confessed above, those favourable listening impressions were formed before discovering just how much, in development effort and exotic materials, has been invested into these apparently humble devices. In my system, they have addressed a significant sonic problem – one that could not have been cured by other means – without any of the aggravation normally associated with ‘tweaking’. On that basis, anyone who has invested substantial time and/or money into optimising their audio system needs to be asking themselves if they can afford not to give these terminators a try.

For the sake of completeness, I’ll mention that the company backs these products with a 14-day money-back guarantee. While a single digital-terminator will often suffice, selling the analog-terminators in sets of three (pairs) is a little awkward for those of us who happen to require four (or five, or seven)! I know they’re cheap, but I rebel at the wastefulness of being expected to buy product I don’t need - hopefully, Alfred can provide a more flexible means for us to purchase the exact quantity required.

If these products sold for three or four times their price then I might be inclined to knock up a set of DIY shorting plugs and attempt to verify or dispute Alfred’s findings; as it is, I applaud him for being prepared to make the fruits of his labour available to us all in products whose high material and cosmetic quality belie their low cost. I recommend both the analog- and digital-terminators as effective, high-value solutions to a long-understood but nowadays underappreciated problem. Who knows; history could yet repeat itself!

Manufacturer’s website

Source of review sample: Reviewer purchase.

Associated Equipment

Analogue: Linn LP12 / Lingo PS / Ittok LVII / Audio Technica OC30
Digital: Meridian 507
Amplification: Custom-built AC Magnum dual mono P200 pre and power
Speakers: Acoustat Spectra 1100 hybrid electrostatics
Cables: MAC Mystic interconnects / Ultimate Cables Silver C4 speaker / MAC HC & Digital power cords
Accessories: Sound Mechanics Performance isolation platforms (on each source component) / Target & Sound Organisation stands / Aerolam & RATA Torlyte shelves / Herbie’s Audio Labs isolation products / Eichmann Toppers / Caig ProGold

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{ 13 comments… read them below or add one }

Alfred Kainz 03.27.09 at 4:50 pm

Thank you for the wonderful in-depth review. I really enjoyed reading it and appreciate it. Of course I’ll consider offering other quantities.

Best regards, Alfred, highend-electronics, Inc.

phil 03.28.09 at 4:07 pm

You are 100% correct. Live with them for a month and pull just the digital terminator and you lose natural detail, placement, etc.

This is one of the best improvements in my system in awhile. Once you catch the improvements it as good as a better power cord or cables…in fact I think you really gain more across the board.

It all starts at the source!

admin 03.28.09 at 6:26 pm

Thanks for the comment, Phil. And welcome to Audiophilia.

Cheers, Anthony

Martin Appel 04.02.09 at 1:46 pm

Hi Andy, I just put in an order for my system but it won’t be shipped till the end of the month of April. I’m really curious.

It’s actually turning Springlik in New York….At last.

Andy Fawcett 04.03.09 at 4:02 am

G’day Marty, glad things are warming up over there. Thanks for taking the trouble to check them out, it’ll be interesting to see how they go for you. As regards the temporary lack of stock, Alfred tells me he’s had a bit of a run on them lately … ;-)

Thanks for the feedback, Phil - hopefully other owners will chip in with their impressions.

Louis Alperstein 04.10.09 at 4:40 pm

Being an avowed, self proclaimed audiophile for 30 or so years, I’m always amused when tweaks like this enter (or shall I say, re-enter) the market. Of course, as you know, the mantra of every scientist is can the audio improvement be supported by double blind studies. I suggest not. In my humble opinion, if you want to improve your audio system there are better ways to do it. It does however, make for amusing reading, but one has to approach such articles with a skeptical eye.

admin 04.11.09 at 6:30 am

Thanks for your comment, Louis. Welcome to Audiophilia. I certainly understand the skepticism. I feel somewhat fortunate that some tweaks have worked for me. I think! :)

What have you done to your system that made a difference.

Cheers, Anthony.

Matt 04.11.09 at 6:30 am

Interesting review Andy!

Do the plugs work by ’shielding’ the inputs or by completing the circuit?

Andy Fawcett 04.11.09 at 11:50 pm

G’day Louis, and thanks for your input. Skepticism is a vital element in any such investigation, agreed … so too is open-mindedness. Double blind testing is, in most cases, completely impractical. Even had I used it here to verify my conclusion, would that make it any more likely that you’d achieve exactly the same result in your system? Absolutely not. The whole philosophical justification for DBT, ultimately, rests on a single core assumption … and that assumption is fatally flawed.

Always nice to hear from you, Matt … though you know better than to ask me intelligent questions! The exact mechanism by which the plugs work is beyond my ken, though I have encountered no dispute that shorting is an effective antidote to RFI pickup.

Mike 01.21.10 at 2:28 pm

Hello ! i was wondering if you can explained how these help ? Do I need to do all unused RCAs and if I want to try home made first how is that done ?

admin 01.21.10 at 3:41 pm

Hi Mike:

Welcome. I’m sure Andy will answer your question in due course.

Cheers, a

Andy Fawcett 01.22.10 at 8:59 am

hopefully my article thoroughly covered the how and why of shorting plugs’ effectiveness. Certainly you should short out all unused inputs for maximum effect. DIY is easy - open up an RCA plug and run a short wire between the two terminals, replace the cover and you’re done. Remember - inputs ONLY … and let us know how you get on!
All the best, Andy

phil 03.13.10 at 1:12 pm

I wanted to follow up now that I have had months to use the digital terminator. It is even better than I first thought. I added on sound panel between my speakers that I had laying in the closet for the heck of it.

Well my jaw dropped, I have my corners paneled and 1st refection points etc, but never thought much of putting one behind in the middle of the speakers. Well I am glad I did.

Not only is the digital terminator affect, it way past that, I pulled it just to see what would change with having the addional panel in place, well pulling it was much more evident than before. 15 seconds or so back on and all was right.

I can now hear the improvement much more that I did before, imaging, bass detail, dynamics all improve. I do use the Cardas RF caps on my unused RCA inputs on my amp, preamp and the outputs on the CD player, gain less noise, better imaging etc.

Toegether a stellar improvement across the board. I just purchased 4 shorting plus from the phono section of my C2300 preamp. I will keep the Cardas in place on the unused RCA inputs due to now knowing the internal design of the C2300, the XLR made be part of the RCA curcuit thus risk of damging something the Cardas caps to a great job and they are safe to use regardless of design.

Looking forward to see if the 4 shorting caps improve anything when used on the phono inputs.

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