Grounding problem with a dedicated line?

@jea48 I think that you have asked some great questions, sorry I cannot inform you further, I have no idea about the CAT grounding scheme. Yes, the CAT in your example is very similar to my model.
At this point, I am going to try my Rowland to see if the problem exists with that in the system...and with the Esoteric still on the convenience circuit, if it does, it is a simple matter to put the Esoteric on the dedicated line...if it does not...well then I am a little stumped. Once I remove all my gear and rearrange things, the next...and hopefully last step, is to put the Jadis and all the other gear on the dedicated line. If that fails to solve the problem...ugh.

 

Tonight I used the Rowland ss amp on the dedicated line. No issues with the Esoteric on the convenience line.
So, I guess the next step is to try all the gear (Jadis in the system, Rowland out) all on the dedicated line, and see if that solves the problem...
I guess the internal grounding of the Rowland is compatible with the Esoteric grounding...
Question...
Would the fact that the Rowland utilizes a choke power supply have anything to do with this....?

The choke gives off a slight hum...and has always done this.In the past, Jeff replaced the choke power supply with a transformer design, but told me that he did this only for his Far East customers, who were super sensitive to any hum, but he felt that the choke power supply was superior to the ‘updated’ transformer...when it came to pure SQ. So, when Jeff totally modded my amp about a year ago, at his urging, we left the choke power supply alone.

 

The choke will be in the filtering circuit after the mains transformer. Whether or not there is a choke there should have no impact on grounding. This I think shows the difference Choke or Capacitor Input?

What you are seeing is the classic problem of single ended connections - any ground interference between one power socket and another is added to the signal, because the interference current flows in the shield of the interconnects.

That one amp is more sensitive to another to this effect depends on how the zero voltage signal reference is connected to the safety ground. Some amps make a hard connection, some via a ground lift resistor (typically 10 ohms for a power amp to 470-ish ohms for a preamp). Some amps have a switch on the rear panel so that you can select ground lift or grounded. The idea is that the relatively high resistance between zero voltage ground and safety ground causes much less interference current to flow, and hence less buzz. Basically if amps have a grounding mode switch on the back panel, you frig around with them until the hum and buzz go away.

This is a little light bedtime reading that sets out the issues https://www.rane.com/pdf/ranenotes/Sound_System_Interconnection.pdf

 

Isn't there some fix that could be employed in the amp(s) using resistors or diodes so that the chassis and signal ground are not the same? I'm above my pay grade on this, but I seem to remember this suggestion viz the Lamm amps, which apparently suffer from the same problem as the Jadis. This could eliminate the need for cheaters or transformers.

 

Thanks for the reply. Reading your link above, if one isn’t utilizing a balanced connection, all is apparently lost.

 

Bill, I do think that contrary to some opinions, that Vladimir Lamm and Andre Calmette actually do know what they are doing with this stuff! I too question what the fix is with their gear, but I am hopeful that having everything on the same dedicated line will be it.

 

It would depend on how many places the circuit ground is connected to the equipment grounded chassis. It may just be impracticable to make the changes needed.
I believe Ralph Karsten mentioned that in one of his posts on this thread. Or maybe it was on Agon or AA.

I vaguely remember Al (almarg), you, and me, a few years back discussing the problem with the circuit grounding of your Lamm amps. Just going from memory I believe you said some one prior to you owning the amps lifted the signal ground from the equipment grounded chassis. They worked and sounded fine that way. It wasn't until you sent them to the factory for a check up where the tech/owner (Vladimir Lamm) reconnected the circuit ground to the equipment grounded chassis. Sound about right?

You could take the amps to a qualified tech, that you trust, and have him lift the circuit ground from the chassis again. Or you could have him install a 10 ohm resistor in series between the circuit ground and chassis. That's how ARC does it, or at least ARC used to.


I believe this is a method used by Bryston.
Look at the circuit to the left of the IEC inlet connector.
Header above the circuit,
"To central power supply ground"
Variations of DC Main Filter against buzzing Toroid Transformers - what is the right? - diyAudio



.

 

@ DaveyF,

Do you have a multimeter? If not you can pick up a descent one at Home Depot for around $50.00.

Test:
Unplug all your audio equipment from both wall duplex outlets. (This is a must for the test)
Set the meter to AC volt auto. Measure from the equipment ground contact on the convenience circuit duplex outlet to the equipment ground contact on the dedicated circuit duplex outlet.

.

 

The dedicated line has nothing to do with this. This is a problem caused by poor internal grounding design on the part of Jadis and Teac and can't be fixed by any home wiring installations unless you have knob and tube which has no ground connection.

Jeff knows what he is doing and made sure his amps aren't susceptible to ground loops.

A person could certainly fix the Jadis. The problem is as I've pointed out that the chassis and circuit ground are the same thing (same thing that was a problem on the Lamm). When any audio electronics is set up this way its susceptible to a ground loop. I'd have to take a look inside to see how hard it would be to lift all the chassis ground connections and star ground them to the power supply. Then you just put a resistance (the double diodes work too) between the chassis ground and circuit ground. At that point the ground of the AC power cord can be tied to chassis and no ground loops.

I hate to put it this way but in the 21st century ground loops are a pretty stupid problem. In a nutshell audio manufacturers, especially high end audio manufacturers, should have this stuff down and not be doing 1950s stuff that doesn't work.

Sorry about the soapbox.

The Teac might be easier to repair since there is only one being used rather than two. You can get away with one component that is improperly grounded to the AC line but not two. It takes two to tango.

 

Ralph, I am with you, why one earth in this day and age is grounding a chassis such a big deal...

OTOH, I happen to think that there are so many thoughts on this stuff....some people even think that OTL's are simply an explosion waiting to happen, for example!
Let's face it, this industry is basically a cottage industry with minimal exposure to the public. As such, I think there are a ton of practitioners who probably could do with a refresher course in electronics at their local community college! I'm not saying that Andre or Vladimir are in that category, far from it actually, or for that matter the engineers at Teac/Esoteric. Ok, I'm just

 

Let me try that. I will report back.

 

You'll get no argument from me. I like Lamm's SET amps. And i've certainly heard Jadis over the years- someone I know just got the two chassis preamp. Loves it.

 

The reason grounding the chassis is a big deal is two fold. First, it can provide some shielding (but its lousy for circuit return currents, which is why grounding the audio to the chassis is a poor practice). Second, its required for all products entering the EU and other countries. Any manufacturer that does not ground their chassis is also taking a bit of a liability risk- all that has to happen is the equipment damaged in some way in shipment and someone could be easily zapped or the like when they plug it in.

So the chassis should be grounded. The lame thing is when a manufacturer doesn't know that the audio circuit ground can't also be the same thing. Being the 21st century and all, its pretty easy to find excellent articles on proper audio circuit grounding. Grounding itself can be a rather obtuse and complex subject, but the techniques for making sure you don't have ground loop problems are pretty simple.

 

There is a confusion here. The green (US) or green/yellow (EU) wire coming in absolutely has to be connected to the metal chassis - that is the safety ground. Under no circumstances frig with that - it keeps you safe.

In addition, there is the zero voltage signal reference - in other words what the circuitry in the amp is connected to, and is what the amp looks upon as zero volts.

Now some amp manufacturers make a hard connection between the two, which is a sure fire recipe for hum loops. Or the amp manufacturers who appreciate the problems, put a resistor between the zero voltage signal reference and chassis ground. That does not compromise the safety ground in any way.

 

Well, no. But for single ended it is a lottery whether you get a system with low noise, or a buzz-meister. My criterion is that any mains power related buzz should be below the hiss level. If it is higher or significantly higher, you still have work to do.

Jensen transformers recognise that there is a problem here, and manufacture a line of galvanic audio transformer isolators to break hum loops. Home Theater | Jensen Transformers . About $200 for a stereo unit with phono inputs, according to Amazon.

Progressively I've gone balanced throughout, and the buzz can only be just about heard with your ear pressed to the speaker cones, even for moving coil phono (yes - a balanced phono stage). And you really do just connect it up and - job done. No messing about. Which is why all professional applications, from recording studios to rock concerts all use balanced.

 

The Jensen transformer looks to me like a possible solution to the ground noise, while at the same time a nice impediment to the overall SQ of your system, just saying

 

Use of transformers in both the inputs and outputs of classic era mixing consoles (such as Neve) was the norm. Bet you don't hear those. There is absolutely nothing wrong with compentent audio transformers. How about tube amplifier interstage transformers from Lundahl? Or Audio Note, who use input, interstage and output transformers in most of their designs How about the output transformer on tube power amps? Or a moving coil step up transformer? How about the very highest grade phono stages that use inductive RIAA correction?

Impediment to sound quality? I don't think so. And certainly not from Jensen.

 

Except the examples you are using were all part of the original design and hardwired to the circuit, or are required to boost the signal to the preamp..( which I feel also leads to throwing the baby out with the bathwater). The examples given need additional ic's and therefore allow for considerable losses of the signal. In a pro audio set up, I would say that would not be an issue, in a high end set up, not so much...

 

OK - you're on your own. I've tried to make useful comments, but you just aren't listening. Good luck with the hum and buzz.

 

I appreciate your thoughts, unfortunately I have been an a'phile for decades and know fully well that we can go backwards just as easily as we can go forwards. Inserting another piece into the line, adding more connections and utilizing another set of ic's is asking for trouble when it comes to SQ.
Not that this may not do away with the possible grounding issue, but it will more than likely degrade the SQ as well. Personally, and I know this is a personal choice, I would rather have the buzzing, which is quite low in level, than have a veil placed over the music by the addition of more cabling and this transformer...which needs to be placed upstream of the amps and the speakers. Nonetheless, appreciate your input.

 

You may recall that I suggested the Jensens as well. Keep in mind that I run Atma-Sphere, a company known for transformerless audio designs and on top of that was the first in high end audio to produce balanced products. Now with that in mind, I have to ask how it is that you know that the Jensens will be a degradation without having tried them? The simple fact of the matter is that when you have a ground loop, its more than just a buzz or hum. Its also degrading the sound you get because the return circuit (ground) is full of noise and it intermodulates with the actual signal. So there is a very good chance that the Jensens will cause an overall improvement due to less distortion (and they have wider bandwidth than the Esoteric). That's pretty audible. Jensen has long made some of the best stuff out there and is found in many recording studios and high end audio products. I wouldn't sell them or yourself short here...

Now it would be better if the ground loop were fixed. But that means that someone would have to modify either your amps or the Esoteric. We could do the amps but there's shipping to think of. The Esoteric might be repairable too but its a guess as to how badly they screwed this up. So you could wind of flushing some dollars down the loo finding out. That's why the Jensens are a good idea- this is what they are for and we know they work.

 

This is what I will try next. There is no potential for SQ loss here, and while it isn’t easy for me to do, given the amount of gear upheaval it will result in, it is the cheapest and hopefully the best fix.

 

Yes I would say get to this asap, if you want to enjoy noise free tunes, I would say stop procrastinating. The results you find, and especially if the problem
disappears, would be most instructive to others. Have fun!

 

I've just been looking at Atma-Sphere's website. Kudos and respect - they look like truly superb pieces of exceptionally high quality and beautiful pieces of gear.

 

I managed to get the system all onto the dedicated line tonight. Took me almost an hour to make that happen, but we are there now. With the large ss Rowland in the mix, I noticed that there was slightly less background hash, and any residual noise from the Esoteric was gone. I also noticed something else, I had to increase the gain on the preamp by about two notches up. This in order to get the same volume as I was getting prior to the switch. Very strange, and makes me think that somehow the power amp, preamp, and SACD player on the same line may be robbing some power from the preamp or amp...if that’s possible. Next up,I replace the big ss amp with the Jadis mono blocks. I will report back once that is up and running.