See above post #1
“If you use the Nordost then everything is floated (without using cheater plugs) except for one socket where the preamp is plugged in.”
Spectral amps and lifting their grounds
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“If you use the Nordost then everything is floated (without using cheater plugs) except for one socket where the preamp is plugged in.”
Elliot sells these so he might have more insight as to how the product is designed. It has to be safe to sell in the EU. Looks like a few WBF members use the QRT products.
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Just installed Nordost QX4 and Q Base 8 Mk2 in my system today
I have been playing around with power products and in particular products that I am able to use at the Audio Shows we participate in. Most hotel rooms have insufficient outlets and not the cleanest power. I installed this today and I am letting it run in. My initial reaction is very positive as...
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I’ve read the product manual which I believe shows the connections; been a while thoughElliot sells these so he might have more insight as to how the product is designed. It has to be safe to sell in the EU. Looks like a few WBF members use the QRT products.
Just installed Nordost QX4 and Q Base 8 Mk2 in my system today
I have been playing around with power products and in particular products that I am able to use at the Audio Shows we participate in. Most hotel rooms have insufficient outlets and not the cleanest power. I installed this today and I am letting it run in. My initial reaction is very positive as...
Not knowing anything about what Nordest does I don't have an obvious answer, sorry. They may use another grounding scheme to render the product safe (there are several ways to do that), or may simply ignore the safety ground (as well as any safety certifications) on the other outlets. There are varying degrees of "float".
I had an issue with my subwoofer and added a UL-approved power resistor to increase the impedance from signal ground to safety ground without affecting safety. There are UL (etc.) rules for what you can do, and of course you have to be willing open up the amp and solder in the component(s).I am absolutely the wrong guy to ask why some of the manufacturers are comfortable selling what they do since I tend to look from a technical point of view rather than subjective or marketing when it comes to many such things. (There are tweaks that do what they say, but in all such cases I have been able to measure as well as hear the result.) I will say I have seen a few power strip isolators that just opened the ground and resulted in a shock hazard. None had the usual UL/CE stickers, although one actually had counterfeit stickers (!)
But again I do not know what Nordest does nor how they are certified and test compliance. It's probably perfectly safe; I do not know either way.
Sorry - Don
Not knowing anything about what Nordest does I don't have an obvious answer, sorry. They may use another grounding scheme to render the product safe (there are several ways to do that), or may simply ignore the safety ground (as well as any safety certifications) on the other outlets. There are varying degrees of "float".
I am absolutely the wrong guy to ask why some of the manufacturers are comfortable selling what they do since I tend to look from a technical point of view rather than subjective or marketing when it comes to many such things. (There are tweaks that do what they say, but in all such cases I have been able to measure as well as hear the result.) I will say I have seen a few power strip isolators that just opened the ground and resulted in a shock hazard. None had the usual UL/CE stickers, although one actually had counterfeit stickers (!)
But again I do not know what Nordest does nor how they are certified and test compliance. It's probably perfectly safe; I do not know either way.
Sorry - Don
Thanks for the response and candor. So let me ask this then: what about older equipment, like my Revox and Nakamichi, which feature no earth ground at all - simple 2-wire cords. Are they less safe?
They are double insulated, so no ground required. I'm not sure about their safety record...
I'd look in the Nordost box, you can see what's there, or not. You can also measure resistance from receptacle ground to IEC ground. If it's infinite you know it's completely disconnected.
If everything is plugged into a conditioner with common ground, that Schurter ground choke may be a solution for your amp, ground straps from pre to amp may reduce noise, and will definitely increase safety if you keep the amp's ground floated.
I did not. When I first encountered the hum/ground loop, I tried a cheater plug. It worked, but was ugly and being a typically insecure audiophile, I worried if the SQ suffered (how could it not, there are no $1,500 cheater plugs
. So, I surmised that removing the ground on the inside of the wall socket and safely covering the end and moving it out of the way was the best solution. Three DMA generations and two houses later, I have never looked back or had an issue.
OK got it, thanksI did not. When I first encountered the hum/ground loop, I tried a cheater plug. It worked, but was ugly and being a typically insecure audiophile, I worried if the SQ suffered (how could it not, there are no $1,500 cheater plugs
"Double insulated" is a simplistic term but applies to many such products. I have owned several Studer and Revox tape decks in the primordial past as well as Nakamichi units (well, repaired them, did not actually own a Dragon, alas), along with much other gear then, and things like an electric drill and sander, that are also double insulated. It means there is no path to external surfaces in the event of a fault so you don't get shocked. So, safe, no worries!
In my techie days and occasionally since I have dealt with cases where a cheater plug was used and led to expensive repairs. Probably one of the worst in recent years was a server (computer) on which a customer had removed the safety ground to install in an older office building. Returned for repair of a drive board, I connected a wideband probe and powered up the system to check the signal integrity. Zap, poof, and a $30k USD probe was fried. Vexing, and I was very lucky I was not in the path. While I have endless shocking stories from my soundman days, the scariest moments were when I did not notice somebody had cut the ground pin and I got set on my butt when I was doing a house call on a TV or some appliance (freezers were a biggie, as were old radio/TV/stereo consoles). There are some old pieces of gear that can be unsafe; built long before codes were in place and the danger was recognized. I got to where I would check the chassis or outside of the component before starting to work.
Also a few stories from my brief stint as an electrician but that usually a mistake or incompetent installation.
My personal horror story (and why I tend to be so anal about this) involved a friend of my father-in-law. He had a benchtop bandsaw and cut off the ground pin to use an old two-wire extension cord to plug it in. The saw was mounted on a wooden platform he could clamp to his metal worktable. He was cutting some water pipe when some lubricant (used to keep the blade cool whilst cutting the pipe) spilled on the saw. He was electrocuted. His grandson found him when he went to tell him dinner was ready. The coroner noted burn marks on the hand gripping the pipe and forearm resting on the metal work table, and we measured the full line voltage across it all. It was OK until the lubricant created a new ground path through his body.
Every time I bring this up there are the usual "I've been doing it for years, never had a problem, and it sounds better that way, you don't know what you're talking about". I don't care. Dead don't care. A shorted power supply or bad transformer can ruin your day. It is safe until it is not and the consequences can be dire.
Thank you all for your responses, this has been tremendously informative. So here's why I really started this thread. As quoted in the original post, the dealer says 'use a cheater plug'. These types of discussions go back years, and when I brought up all kinds of possible safety issues and expensive repairs, the eventual response by the dealer was that all this information really comes from Spectral. When asked why they don't mention all of that in the manuals, the response was: what if they get sued and go down.
So to clarify, I am not saying Spectral directly authorizes lifting the ground, but I am saying the dealer told me (and possibly many other users) to use cheater plugs (as quoted from a couple of months ago) and that he's said the factory originated this information to him. It would be best to first talk to one's own Spectral dealer first.
So to clarify, I am not saying Spectral directly authorizes lifting the ground, but I am saying the dealer told me (and possibly many other users) to use cheater plugs (as quoted from a couple of months ago) and that he's said the factory originated this information to him. It would be best to first talk to one's own Spectral dealer first.
Not sure I'd take a dealer's advice over that of an electrician, especially if Spectral is worried about getting sued...
For lower-power components there are inexpensive solutions like a Hum-X AC line isolator or transformers to isolate signal ground (from cheapie $30 RCA units to $1200 Jensen models) and of course various active electronic units along with power strip solutions. Since cable or satellite boxes are common sources of ground loops, there are a number of cable isolators that work on the RF side to break a ground loop.
One thing I have seen done is to run an extra ground wire from the component to a common safety ground tie point. Not completely safe, but provides some redundancy. Always vexing to feel a "buzz" or mild (hopefully) shock when you pull an interconnect that was providing the safety ground for your system.
Ground loops can be insidious. The ones that introduce an easily-audible hum are not a big problem to find and fix; it's the ones that add a little bit of noise or introduce a sneak RFI/EMI path that raises the noise floor from dead silence to a tiny little raspy buzz that are really annoying and often harder to track down. Back in my techie days, I used to say it wasn't the blown amplifier that was hard to fix, it was the one that had 0.05% distortion instead of 0.01% that was a pain. Or 0.005% instead of 0.001%...
For lower-power components there are inexpensive solutions like a Hum-X AC line isolator or transformers to isolate signal ground (from cheapie $30 RCA units to $1200 Jensen models) and of course various active electronic units along with power strip solutions. Since cable or satellite boxes are common sources of ground loops, there are a number of cable isolators that work on the RF side to break a ground loop.
One thing I have seen done is to run an extra ground wire from the component to a common safety ground tie point. Not completely safe, but provides some redundancy. Always vexing to feel a "buzz" or mild (hopefully) shock when you pull an interconnect that was providing the safety ground for your system.
Ground loops can be insidious. The ones that introduce an easily-audible hum are not a big problem to find and fix; it's the ones that add a little bit of noise or introduce a sneak RFI/EMI path that raises the noise floor from dead silence to a tiny little raspy buzz that are really annoying and often harder to track down. Back in my techie days, I used to say it wasn't the blown amplifier that was hard to fix, it was the one that had 0.05% distortion instead of 0.01% that was a pain. Or 0.005% instead of 0.001%...
Yup, indeed. This tiny one I've been trying to fix has been going on literally for a decade, with all Spectral amps I've had, and it's not really the amps. I've always star-grounded, used the same length cords, same interconnects, and yet, no fix for that very tiny leak. My suspicion is that the MIT interconnects are just slightly different somewhere, despite the same model designation "Oracle 50ic"
In fact, never. I've heard them at the dealer's and both he and I prefer the cleaner sound of single-ended.
A wire from the amp chassis to the ground point would do exactly the same thing as the ground in the power cable. IMO, the issue is the grounding in the amp it's self. Connecting the IEC ground pin directly to chassis does not work universally, and it may be the IC grounds are also directly connected to the chassis, so there may be no isolation between signal and chassis grounds either.
There are no standards for how the ground is connected in audio components at all. So it can be a crapshoot and often the solution is adding isolation, be it the Schurter DENO I linked to, a resistor with a cap bypass, a trafo to provide galvanic isolation, etc.
The purpose of the wire is to provide a different ground path, not necessarily the same as the power cord, one that hopefully does not contribute to signal ground noise. But whether it works, or even makes things worse, depends entirely upon the issue in your second paragraph.
Posting just as an FYI: https://www.synergisticresearch.com/accessories/power/ground-lifter/
Their claim: "This device fits onto the end of your SR power cable without degrading it's performance"
Like many of you I question their claim, but at least it's "only" $35 and it likely comes with their 30-day return policy in the US.
Their claim: "This device fits onto the end of your SR power cable without degrading it's performance"
Like many of you I question their claim, but at least it's "only" $35 and it likely comes with their 30-day return policy in the US.
Thanks. I do need to point out that this is just a common Leviton that can be had for about $2. SR are well known for making and marketing crap at inflated audiophile prices, and here we are yet again.
If you look at the photos ack posted, the IEC ground is directly connected to the chassis, so a grounding cable from amp to power distributor would make the same connection. If the wire goes from preamp to amp and the preamp is grounded, then it should improve grounding without allowing the ground loop in question.
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