Marantz 7C Maintenance

By: Steve Greene 

Maintenance.  If you are a hands-on audiophile like many of us, you occasionally face the task of updating/repairing your system’s components and ancillary devices.  I personally love vintage tube audio gear, which has its own set of maintenance chores: checking the tubes periodically with a tube tester, cleaning the tube pins, replacing power supply capacitors, or the notoriously problematic (after 50 years of use) bumblebee capacitors such units may contain.  

For many lovers of vintage tube audio gear, the holy grail of preamplifiers is, perhaps, the Marantz 7 and/or the McIntosh C-22.  These two items from the late 1950’s through late 1960’s have become quite scarce and, as a result, have risen dramatically in price on the popular auction sites.  I was incredibly lucky back in 1993 to acquire a Marantz 7 via a trade of audio gear with a gentleman near the Blue Ridge Mountains.  He had inherited this pristine piece of gear from his uncle many years prior.  However, he became tired of periodic tube replacement and occasional trips to the repair shop for slight issues beyond his own capabilities.  I was thrilled to acquire this piece of hifi history and, having already built a few kits (Heathkit, Dynakit), felt ready to take on a revered component for the long haul.  

The immediate needs for this preamplifier immediately after my acquisition were new caps on the top mounted phenolic board.  One “bumblebee” capacitor (named for their black body, surrounded by colored stripes) had a big crack running from one end to the other.  While many aficionados consider it heresy to replace any of the active components in a vintage (and valuable) piece of collectible audio gear, I now had my excuse to update this preamplifier with some newer, better performing modern components.  I replaced all of the capacitors on the top phenolic “turret” board with boutique-type TRT SETI Infinicaps, a couple Hovland MusiCaps, and fresh Nichicon Muse and Sprague Atom small electrolytics.  I replaced the tubes, six 12AX7A’s, as well.  With periodic tube replacement, this preamp has now served my “upstairs system” exceptionally well for nearly thirty years.  However, as you may have guessed, now I’m going to relate my most recent maintenance on this revered piece of gear…

I have mentioned the top facing phenolic/turret board in the Marantz 7.  It is not a circuit board, the components are hard wired to “turret-type” posts, not traces.  

This board is also attached to a metal flange that contains the horizontally mounted 12AX7A tube sockets, which protrude from the back panel.  To reduce the deleterious effects of vibration (creating undesirable microphonics), this board and metal flange “float” on three metal/rubber suspension screw-in “grommets”.  

Two “new” suspension mounts next to a “bad/broken” mount

These are crucial to the design of the preamp, and mine had (as is common) deteriorated to the point of splitting in the middle of the rubber and separating.  Instead of floating, the board was resting, undesirably, on the chassis.    

Fortunately, an enterprising audiophile/businessman in Hong Kong had acquired a stock of NOS (new old stock) metal-rubber isolation/suspension mounts years ago and kept them in an oil bath, keeping them fresh.  I was lucky enough to acquire a set about five years ago and had been waiting for the perfect moment to install them ever since!  

This week, I got into the proper mood to finally undertake the task of installing them.  The job was not nearly as difficult as I had feared.  In fact, it took me longer to remove all the interconnects and tubes and disassemble the unit than it took to complete the task.  Now completed, the turret board and tubes float on the suspension mounts as they are supposed to!  

While I had the unit open, I took the time to also spray the insides of the balance and volume controls with Deoxit FaderF-5 to lubricate and clean the wipers in these controls, which should eliminate any scratchy issues with either pot.  I also used the same solution to clean the contacts on the selector switch.  Another nice tweak I like to do is clean all the tube pins with an emory board.  This removes any oxidation or possible corrosion on the pins ensuring better contact. If you decide to replicate this tweak, however, make sure to do this gently—you don’t want to thin the pins, which could result in looser tube pin tension.  

Lastly, I checked the tubes on my trustworthy Hickok 800A tube tester. Tube testers are essential if you want to eliminate that nagging, paranoid feeling when you suspect, but don’t definitively know if your tubes are nearing the end of their useful life. In my opinion, too many audiophiles replace tubes before they really need to.  My GE 12AX7A’s in the Marantz 7 have served faithfully for over five years and they still tested strong! While quality tube testers have become pricey on the used market the past ten years or so, I am a firm believer that if you are going to utilize tube components in your system, you must own or have access to a quality tube tester. 

When buying a tube tester, make sure it’s a mutual transconductance-type tube tester, not an emissions tester.  Two of the more common and best performing mutual transconductance-type tube tester brands are Hickok and B&K.  The Hickok 539C is the holy grail of Hickok tube testers but the 800A, 600A, 6000, 533A, 752 and others are all great testers.  I also like the B&K 700 and 707 testers.  If you don’t want to pay the high price found on the popular auction sites, go to a local AARL sanctioned Hamfest. Now that things are opening back up a bit…you might find a bargain!  Realize, however, that testers should be calibrated and the (usually two) rectifier tubes inside them must be good or replaced. 

As an aside, my Hickok was a Christmas gift from my father back around 1989.  When my mother saw it, she was mortified, as she thought he had gifted me a piece of junk (my mother is the same person who was equally mortified back when I, as a teenager, installed a large FM antenna system with rotator on the roof of the family home while my parents were away for the weekend)! I, on the other hand, loved the Hickok! I later told my Dad that the Hickok was the best gift he ever bought me, and I still use this extremely useful tool on a regular basis.

Hickok 800A

So, how does the Marantz 7 sound in my system now that it has been refreshed?  Wonderful!  That’s why I have kept it so many years.  Plus, it has a ton of flexibility with numerous inputs like two sets of phono jacks, four sets of auxiliaries (labeled aux, tv, fm multiplex, fm/am), a tape head, a tape monitor and a set of microphone inputs.  This unit even has two sets of outputs so that I can connect two monoblocs and two subwoofers!  

However, the story has not ended just yet.  I have more work to do at some point in the future… My unit still has the original selenium rectifier that should be replaced with diodes and the original multi-section electrolytic cans for the power supply, which could prove to be a difficult job. I will also probably replace a few more resistors on the bottom side of the unit.  There are lots of carbon composition resistors there that have the possibility of drifting in value and/or getting noisy after so many years.  The tone controls (separate bass and treble for both channels) have a ton of difficult-to-access bumblebee capacitors on them too. They are a paper-in-oil composition which leads to failure from simply picking up moisture after many, many years.  Polypropylene, Teflon or polystyrene capacitors make very good replacements for the failure prone bumblebees, but it would be a herculean task to replace them all! One other potential future chore? Replacing the old-style tin-plated RCA jacks on the back of the preamplifier with new and more robust gold-plated RCA jacks. There is so much on the to do list!  

I would be remiss if I didn’t mention how well our Nordost Valhalla 2 interconnects grip the old-style RCA jacks on this preamplifier.  The HOLO:PLUG RCA connectors do a wonderful job of securely gripping these shallow jacks, ensuring maximum signal transfer.  Those interconnects also contribute greatly to the three-dimensional sound of my system.  In my system, the Marantz 7 feeds a pair of refurbished McIntosh MC-60 tube amps, which I completely rebuilt nine summers ago.  Since I am only using one set of the phono input jacks on the Marantz 7, I have a QKORE RCA wire attached to one jack of Phono 2, which then connects to a QKORE3 Grounding Unit.  This reduces the noise floor of this preamplifier, resulting in even better sound quality.  The preamplifier’s power cord is also plugged into a QB8 QBASE which itself is attached to a QKORE1.  The system is dead silent and sounds sensational, if I do say so myself!  Make sure you ask your local Nordost dealer for a demo of our superior grounding products. I would also highly recommend you ask them for an in-home evaluation of our interconnects, speaker cables, and power cords, since there is no better test than hearing these products in your own system!  You’ll be glad you did!

Like I said, there is still much to be done to my Marantz 7, but that’s the type of commitment you take on when you choose vintage, “golden-age” audio components. Stay tuned, and I’ll let you know the results of my next steps. Is it a lot of work? Yes. But for the right person, the work is well-worth the reward!

How does cable design affect the audio performance of digital cables?

When you’re looking for a digital interface, cable design is of the utmost importance, but what aspects of cable design matter, and how do they affect the performance of your digital cable? There are several electrical characteristics to consider, the top four being: characteristic impedance, capacitance, shielding and transmission speed. 


Characteristic Impedance: 

When speaking about the impedance characteristic of a digital signal, it is important to note that, while you may want to focus on the cable alone, the transmission line of a digital signal starts where the RF signal is generated inside the digital source and ends where the signal is decoded inside the digital receiver. However, for the cable alone, the impedance characteristic is defined as the ratio of voltage to current at the input to an infinite transmission line. The stability of the impedance characteristic depends on several design aspects of the cable, including conductor size and geometry, insulation material and the thickness of that insulation, and connector quality and type (75 Ω for S/PDIF, 110 Ω for AES/EBU, 90 Ω for USB, and 100 Ω for UTP Ethernet cables).


Capacitance: 

In digital cables, high capacitance of a cable will slow down voltage transitions, causing an unevenness to the flat portions of a square wave. When this happens, the D/A receiver on the other end of the signal will have a harder time identifying the data transmission. Many aspects of cable design that help to minimize capacitance are the same aspects that affect the impedance: decreasing the conductor diameter, changing the conductor geometry, and using insulation with a low dielectric constant. The art of designing a high-quality digital cable is finding the balance between what needs to be done to keep capacitance low and avoiding negative impact on the characteristic impedance of the cable. 

To keep capacitance low, Nordost implements their proprietary Mono-Filament technology in their digital cable design. By intricately and uniformly wrapping single or twisted pairs of FEP Mono-Filament around each conductor before encasing them in an extruded layer of high-quality FEP, each conductor is surrounded by its own air dielectric. In decreasing the interaction of the conductor to the insulation, the signal is no longer hampered like it is in more traditional digital cable designs.


Shielding:

Whereas in analog interconnects shielding is used only to keep foreign elements away from the signal, in digital transmission, shielding both keeps external radio frequencies and electromagnetic interference away as well as keeping RF signals inside of the cable itself. When designing a digital cable, one important thing to keep in mind is the compatibility of the specialized connectors with the shielding material, as that will determine how manufacturers implement the shielding into the design. 


Transmission Speeds: 

While fast transmission speeds are always sought after in cable design, for some digital cables it is absolutely essential. USB cables, for example, must perform a digital handshake (where the signal travels from source to destination and then back in 26 nanoseconds) to work. When using a conventional design, that handshake is only possible at short lengths. Nordost USB cables, on the other hand, employ Mono-Filament technology, enhancing signal speeds so much that we are able to build cables twice the length of a standard USB cable or longer, and still achieve a reliable handshake.


For more information like this, to better understand the technical challenges of digital audio data transmission, and to know what to listen for when auditioning digital audio cables read our download, Digital Audio Cables: How Can They Make a Difference?, now!  


How to Make the Most Out of Your Bi-Wired Loudspeakers

Do your loudspeakers have multiple sets of terminals on their rear panels? If they do, they have been configured with a bi-wire (or possibly tri-wire) crossover. This generally means that they were designed so that one pair of terminals are designated for the high frequencies and the other pair for the low frequencies. Great news—bi-wirable crossovers could mean wonderful audible enhancements for your system! But you have to make sure you’re using this design feature to your advantage, or risk tanking your system’s performance.

When using Bi-Wired Loudspeakers, there are three main cabling options for your set-up: supported shotgun, bi-wire, and bi-wire jumpers. This blog will take you through each option and let you know how they can help (or hinder) your system’s performance level.


“Supported” Shotgun:

Typically, you would use a cable configured in a “shotgun” termination with standard loudspeakers which don’t require bi-wiring. You may ask, “With a bi-wired loudspeaker, how could you possibly support both the tweeters (which support the high frequencies), and the woofer (which supports the low frequencies) with a single run of loudspeaker cables? The answer: you can’t. That’s where the word “supported” comes in.

Many bi-wired loudspeakers are supplied with metal links, which connect the tweeters with the woofer (or vice-versa depending on which pair of terminals you have connected to your amps via your loudspeaker cable). To be clear, at Nordost we do NOT recommend this method. By using these standard, metal links, you are effectively throwing away all the good you’ve done (not to mention the investment you’ve made) with your carefully integrated high-quality audio cables in the last inch of cabling. Naturally, your second question would be, “If metal links are detrimental to the sound, why would a loudspeaker manufacturer provide them with their product?”. Unfortunately, that is a cost issue. In many cases those manufacturers don’t want their design to be prohibitive, so to allow you to use their loudspeakers as soon as they’re purchased, they may include these plates (much like is done with the cheap power cords that are often supplied with electrical components). However, when asked, loudspeaker manufacturers would rarely suggest those plates be used as a permanent solution.


Bi-Wire Cables:

A bi-wire cable is a single run of loudspeaker cable that is terminated with four connectors on the loudspeaker-end instead of two (as is done with shotgun speaker cables). This solution allows you to connect all terminals of a bi-wired loudspeaker without having to buy two pairs of loudspeaker cables, or using standard metal links. In theory, this seems like a good solution, and at Nordost we believe it is a better option than a “supported” shotgun configuration. However, when you bi-wire a loudspeaker cable, you are effectively splitting the cable in fourths in order to serve all terminals. As a result, each terminal is benefitting from less conductors, increasing resistance, and compromising the performance of the loudspeakers.

Alternatively, you could also use two pairs of loudspeaker cables running from your amp to the tweeters and woofer of each loudspeaker, respectively. While this may be the ideal solution, it can become costly, which is where the third option comes in…


Bi-Wire Jumpers:

Bi-Wire Jumpers allow you to use one run of loudspeaker cables to connect your amplifier with your loudspeaker without hindering the performance-level of your system, like you do with standard metal links. At Nordost, our Bi-Wire Jumpers are made using the same technology as our loudspeaker cables, essentially offering an extension of the speaker cable itself. This ensures that an identical sonic signature can be used throughout your entire system, without interruption. Bi-Wire Jumpers are a great way to affordably and immediately integrate bi-wire loudspeakers into your system. This can be either a great long-term solution, or a means to tide you over while you save up for that second pair of quality loudspeaker cables.

For more Do’s and Don’ts about Bi-Wiring and to learn how to best configure your Bi-Wire Jumpers, download our guide today!


Cartridge Mounting & Alignment in 6 Easy Steps

An accurately aligned cartridge will keep the needle in the groove, minimize tracking errors, and achieve the most accurate sound from your turntable. Correctly mounting and aligning your cartridge, is a multi-step process that involves several tools, and some patience…but the results are well worth it!  To give you a better idea of how to get started in this task we have simplified the process in 6 easy steps: 

1. Insert the screws and nuts through the tonearm headshell in order to hold the cartridge in place. (Do NOT initially tighten the screws all the way down!) 

2. Once loosely attached, use tweezers to connect the four tiny wires that come from the tonearm to the cartridge’s color-coded ends. 

3. Before tightening the mounting screws to the arm’s headshell, the cartridge’s alignment must be set correctly. Use an alignment tool to align the cartridge. We recommend tools offered by Acoustic Solid, Acoustical Systems, Baerwald, Feikert, Mobile Fidelity Sound Lab, and VPI.

4. Use a “pivot spindle” measuring tool to set the distance between the tonearm pivot and the spindle. This distance should be specified by the manufacturer of your turntable. 

4. Align the cartridge stylus using a mounting template. 

5. Now that all adjustments have been made, tighten the mounting screws. (Make sure not to over tighten them!)


For more information about this, and all things turntable set-up, download our Complete Turntable Set-Up Guide today!

Digital Cables: How Can They Make A Difference?

At Nordost, we try our best to give our customers the knowledge they need to optimize their audio systems and get them performing at their best. One way that we do that is by providing you all with a series of helpful guides ranging from loudspeaker and turntable set-up, to the importance of grounding and vibration control, all available for download on our website. The most recent of these valuable articles deals with digital cables.

Digital audio cables are arguably the most controversial component in hifi. As hifi audio cable manufacturers, when it comes to our digital cables, we are constantly asked two questions: “How do digital cables make a difference in a hifi system if all they do is send ones and zeros?” And, “How does the design of a digital cable help in the signal transfer?”. This informative download breaks down the answers to both of these questions, explains the technical challenges of digital audio data transmission, and lets you know what you should listen for when evaluating the merits of a digital audio cable so that you can upgrade with confidence. 

Download “Digital Cables: How Can they Make a Difference?” today!

Questions and Answers (May 2021)

Our product specialists receive questions on a daily basis about Nordost products, their application, and hifi in general.  We thought that we would take a minute to share some of our most recent and frequently asked questions here so that everyone can get the answers they are looking for!


Q: Can you use the new QRT Stand Mount with older versions of the QBASE? 

A: The QRT Stand Mount was designed to fit the QSOURCE as well as all Mark II versions of the QBASE. Older versions of the QBASE AC Distribution Unit will not fit the QRT Stand Mount.  


Q: What purpose do the detachable ground whips that come with Nordost’s Tonearm Cable + serve? 

A: All ranges that include a Tonearm Cable +, from Blue Heaven to Odin 2, come with two detachable ground whips. These ground whips can be used to ground the shielding of the cables as an additional ground loop prevention when needed. In order to determine if you need to use the Detachable Ground Wires, follow these steps: 

  • First, play some music without any of the Detachable Ground Wires attached and see how it sounds.
  • Then, try inserting one of the Detachable Ground Wires to your cable on the end closest to the turntable. Connect the spade of the Detachable Ground Wire to the ground post on your turntable.
  • Next, if you have a ground option on the phono-stage end, disconnect the Detachable Ground Wire from the turntable end of the tonearm cable, and insert it into the phono-stage end instead. Connect the spade of the Detachable Ground Wire to the phono-stage ground, and listen again.
  • Finally, if applicable, insert both Detachable Ground Wires to the two ends of your cable, connect them to ground on the turntable and the phono-stage, and listen one last time.

Q: Is the Valhalla 2 Ethernet cable shielded? 

A: Yes the V2 Ethernet cable is constructed using individually shielded conductors, arranged in twisted pairs, which are then wrapped in braided, silver-plated copper shielding, before being encased within a high-density polymer insulation. This fully shielded cable construction virtually eliminates the crosstalk and electromagnetic interference (EMI) that has always afflicted previous network cables.


Q: When I’m auditioning Nordost’s QPOINT Resonance Synchronizer, what should I be listening for?

A: When auditioning the QPOINT, listen for the following improvements: 

  • Greater musical organization, focus, and coherence 
  • A controlled sense of dynamic freedom and force to the sound 
  • Instruments maintaining their natural quality 
  • Vocal separation and three-dimensionality

Grounding Your Hifi Audio System: “Natural” vs “Artificial” Ground

When “grounding” an audio system, the first thing that audiophiles do is make sure that their AC receptacles are in order. This is a great first step! It is vitally important that the AC line and load wires on all receptacles being used in your hifi system are correctly phased and properly grounded.

However, if you really want to address earth ground, the most practical and worthwhile upgrade is to install a dedicated circuit for your audio system. This step should be followed by installing a separate, external ground path to an external ground rod. Each of these solutions provides a path out for unwanted, “spurious” currents that circulate through the circuit and add noise to the system. Unfortunately, these measures ONLY address earth ground, and don’t do a thing to address signal ground. 

Signal ground becomes a problem whenever currents are generated during transmissions between devices in a system as a result of the small differences of potentials in those components. In order to rectify the background noise and loss of low-level details caused by contaminants on the signal ground, you need to elicit the help of an artificial ground. An artificial ground is a sink of impedance lower than the house earth ground, so that high-frequency noise on the signal ground will drain away, leaving a clean reference behind. 

Signal ground can be addressed two ways. The first option is to use an extremely low-impedance cable to connect the signal ground access point on the termination to the ground pin of an unused wall socket. However, the second option is far more versatile – a passive grounding box. Nordost’s answers to artificial ground are their QKORE Ground Units, a series of parallel grounding devices which can either separately provide an artificial “clean” earth for the primary side of the power supply (earth ground) with the QKORE1, and the secondary side (signal ground) with the QKORE3, or can address both the signal and earth ground together with the QKORE6! 

For more information about grounding your audio system, download The Importance of Electrical Grounding in Audio Systems.

Nordost Sort System: How to Get Your System’s Vibration Under Control.

Along with poor grounding, unwanted vibration may be one of the most ubiquitous problems in hifi. Damaging vibrations, no matter the source, have the ability to alter sound causing distortion, disrupted imagery, and even timing issues to the music you’re trying to enjoy. Not only is vibration a ubiquitous problem in hifi, but it’s pervasive throughout the system– affecting your components, loudspeakers, audio racks, and even cables. Luckily, ridding your system of unwanted vibration can be easy.

Nordost has not only introduced one anti-vibration product, but an entire Sort System made up of three products that are uniquely specialized to combat vibration, depending on the element of the system they are addressing. Unlike other anti-vibration products on the market, which define themselves as either isolation/de-coupling or coupling devices, Nordost’s Sort System takes a different, more comprehensive approach: resonance control. (For a deeper look at the difference between isolation, coupling, and resonance control, check out our blog: Three Ways to Address Vibration Control). The following will help you better understand each of Nordost’s Sort devices and show you how they fit into your system to help you rid unwanted vibration. 


Sort Kone

The Sort Kone is designed to address vibration occurring within components. It is built using a unique three-part construction, which creates a mechanical diode. When pressure is applied to the Kone, a one-way path is established through which the internal vibration produced by moving parts in the chassis of electronics can escape. When you place Sort Kones under audio components (a minimum of three Sort Kones per unit is required) music becomes more focused, there is an increase in depth and transparency in system performance, and the dynamic range is broadened. Nordost Sort Kones are available in three levels of performance (aluminium, bronze, and titanium) to fit a wide range of system and budgetary needs.


Sort Füt:

The Sort Füt is a mechanically tuned resonance control device designed to address the vibration generated both within loudspeakers and through audio racks. It is purpose-built to enhance the performance of your hi-fi system and improve upon standard spikes and stabilizers. The Sort Füt’s proprietary four-part construction eliminates unwanted vibrations by providing a direct ground path out, allowing extraneous energy to escape either the loudspeaker or audio rack it is attached to, while simultaneously preventing external vibrations from traveling back through the device. The result: a reduction of intermodulation distortion, a proliferation of musical information, and an increase of tonal and textural details that will allow your system to achieve the dynamic range it is capable of.



Sort Lift

The Sort Lift is designed to minimize the points of contact that cables make with the ground and reduce boundary effects, without negatively affecting the resonant properties of the cables themselves. Each Lift is composed of two integral components: the base and the springs. The base inhibits any transference of electrical charge from the floor to the cable and eliminates static build-up on the dielectric itself. The springs use flexible, titanium alloy spring-wire, which makes up both the support wings and tension wire supports. Both elements of this floating spring system are coated in FEP, mirroring the design of Nordost cables and making the supports an extension of the cable jacket, eliminating any electrical interference, while allowing the cables to maintain their natural resonance properties.


To learn more about our Sort System or to arrange a demonstration, contact your local Nordost retailer
For more information about vibration control, including how to identify different types of resonances, their sources, and how to manage those harmful vibrations, so that you can enjoy your sound system to its full potential, download our guide, The Importance of Vibration Control, today.

Quick Guide to Turntable Acronyms:

Technical jargon and industry shorthand can be intimidating and confusing when you are just becoming familiar with a hobby—and hifi has PLENTY of it! We thought we would save you a trip to your google-machine, and spell out what some regularly used acronyms mean when talking specifically about your vinyl set-up! 



ASF (Anti-Skating Force)—

This is the equal but opposite force that turntables use to counter the frictional vector force that pulls the tonearm towards the center of the record (also known as “skating”).


VTF (Vertical Tracking Force)—

The amount of “weight”, or downward force, that the cartridge stylus exerts on the grooves of the record. This force can be measured by the stylus force gauge, and adjusted by sliding the tonearm’s counterweight forward or backward to achieve a specific weight range specified by the cartridge manufacturer.


SRA (Stylus Rake Angle)—

the angle at which the stylus is raking the record grooves. The optimal SRA angle is the angle at which the record grooves are cut (in most cases 92 degrees). 


VTA (Vertical Tracking Angle)—

the angle at which the cartridge stylus sits in the record’s grooves when viewed from the side of the tonearm (this in turn, determines the SRA). 


PRaT (Pace, Rhythm, and Time)—

This is often used to qualify how good or realistic audio equipment is at sound reproduction. Does it make you move? Is it toe-tapping? 


For more information about turntable-related terms and turntable set-up in general, check out our Complete Turntable Set-Up Guide!


What’s the difference between Earth, Signal, and Chassis Ground?

If you have gone through, or are currently in the midst of, constructing your ideal sound system, you have come across the term “grounding”. Achieving a clean reference ground is postulated as the holy grail when it comes to having the ultimate high-end audio system. However, it is important to understand that when talking about “grounding” you could potentially be referring to three separate things: earth ground, signal ground, and chassis ground. Here, we are going to look at all three ground variations, to clarify the differences between each one, and hopefully help you identify which “ground” you need to address in your home system.


Earth Ground refers to a direct, physical connection to earth, or an electrically neutral body. By connecting a ground wire in your system to “earth”, whether it be directed to an artificial ground or natural ground, you are providing a path for extraneous current. When earth ground is being addressed, you are effectively draining the system of unwanted, “spurious” current that is circulating through the circuit and adding noise to the background. In order to confront problems with earth ground in the system, Nordost offers two solutions: the QLINE and the QKORE (specifically the QKORE1 and the primary side of the QKORE6).


A signal ground is an analog or digital ground that is attached to every signal being transmitted between devices in a system. Since these devices are usually powered separately, it is inevitable that there will be small differences between their potentials, causing small currents to circulate in order to compensate. These currents add to the background noise, obscuring low-level detail in music reproduction. Furthermore, as there are usually multiple signal ground paths in a system, those ground paths can pick up on each other’s interference. Nordost’s QKORE3 and the secondary side of the QKORE6 attract those currents, leaving a clean reference point for the signal ground.


A chassis ground refers to the connection that establishes an electrical link to a metallic enclosure. Describing chassis ground can be confusing because, when speaking about audio equipment, a chassis ground can differ depending on manufacturer. A chassis ground can be connected to the earth ground if it’s meant to prevent electrical shock, or the signal ground when intended for shielding. It can also connect the earth to signal ground, or it can even float. No matter how the chassis ground is connected to the earth and/or signal ground, the previously mentioned products and solutions offered by Nordost will help your system address the chassis ground. Additionally, Nordost’s Tonearm Cable + can help address the chassis ground, depending on how the ground whip is implemented.   


For more information on grounding, download The Importance of Electrical Grounding in Audio Systems today!