Ground loops in big CJ Monoblocks

[AnotherJohnson]

Regular visitors may recall that components in my system with the LP275Ms need to be plugged into the same ground strip to avoid ground noise.

I asked Conrad Johnson if there was a possible bad ground in one of my LP275Ms (loose wire, bad socket, or something).

Essentially I was told no. This ground noise is inherent until you plug everything into the same power strip.

So … it’s normal. If you’re battling ground noise in a system with CJ monoblocks, consider this solution. It’s worked in four different locations for me.

Here’s what was actually shared:

CJ wrote
“ Ground loop hum can occur in any audio system , the greater number of
audio components , the more sensitive the system is to generating ground
loop hum, which is heard from the speakers. Think of it this way , the
shield/ground of your audio interconnects, and the ground wire inside
your audio component AC line cord, and the ground wire inside the walls
of your house, are all connected together , they form a very large
antenna. All of these physical ground wires are sensitive to AC 60hz
mutual inductance. This ac signal is riding on the ground of the audio
interconnects and is then amplified by the preamp and power amp. So ,
using monoblocks versus a stereo amp adds an additional ground thru the
additional ac line cord. This ground loop scenario is simple to resolve.
Use audio interconnects as short as possible , 1-2 meter , connect all
audio component ac line cords to 1 AC line passive strip. Your goal is
to minimize the physical size of the ground antenna.”

[AnotherJohnson]

FWIW, this issue is so common that CJ fields this question every day.

“ With thousands of CJ customers , we get this same question everyday , quite common in the high-end audio world.”

So it truly is normal behavior.

I can’t help but wonder if balanced interconnects, and a Faraday Cage around your room wouldn’t help too.

[admin]

Yes. I've certainly had my share of ground loop issues with CJ in the past. They can be resolved by following these instructions and a bit of experimentation.

[AnotherJohnson]

The antenna concept is difficult for me because my RFI/emi sniffer says we have very little background noise here.

But the ground loops are real. I’m glad they go away with the use of a single power strip.

[AnotherJohnson]

Speaking of Faraday Cages,

https://faradaylabz.com/products/canopy ... zzEALw_wcB

[admin]

Speaking of Faraday Cages,

https://faradaylabz.com/products/canopy ... zzEALw_wcB

That's funny. Like Barnum said, there's a sucker born every minute.

[AnotherJohnson]

You know it could double as mosquito netting in a climate where malaria is an issue.

Maybe they make one big enough for a whole audio system. I wonder if the remote control would penetrate it.

[admin]

You know it could double as mosquito netting in a climate where malaria is an issue.

Maybe they make one big enough for a whole audio system. I wonder if the remote control would penetrate it.

IR remotes should as the netting merely cuts out a small percentage of the signal, RF based ones (like roku/fire/wireless game controllers) should not if it truly works as an effective Faraday cage.

[AnotherJohnson]

It turned out that while the ground issues may be normal at CJ, in the case of my pair of LP275Ms, an independent but skilled and diligent investigator found some actual defects in the form of a cold solder joint and an inadequate solder fill.

So … if you have this issue with your CJ gear, you may want to more aggressively insist that CJ put it on the bench even if they don’t want to. Maybe it’s normal … but no other marques require the single power outlet kabuki dance, and if your CJ is right, maybe yours won’t either. Just sayin’.

[Big Dog RJ]

Yes, very good point AJ.

I've had my fair share of hum issues on my monoblocks as well. The last one being a pretty annoying hum from the right channel, plus people talking through radio freq (the antenna concept...) from the left channel and whenever a light switch was on / off in the guest room toilet, it caused fairly loud pops from both channels!

I wouldn't tolerate this one bit... so I hired a well know electrical company to send out two techs to fix the bloody thing. They ran separate wiring from mains board to monoblocks then changed switches and did a full diagnostic testing on all circuits. Apparently the audio gear is wired on a dedicated line so no issues there but that hum, radio station and pops just wouldn't go. Finally, the chief tech said it's definitely a problem with the monoblocks!

This was after the amps arrived from a Teflon cap upgrade from the CJ importer... so I didn't send them back there. Instead I called up my local techie, he took one look at the amps and a damn ground wire (green color wire) had come loose! Go figure!

That's all it was, nothing else! Then of course I got the amps further modded by him plus the full SE upgrade kit, and now there's pin drop silence! It's a beautiful thing!

I must say though, I never had these sorts of hum and buzzing issues on other gear, VTL, Manley Labs, Sonic Frontiers, Golden Tube, Jadis, Audio Note and ARC. Only on CJ gear... so if it's there, it must be checked out!

After all, we purchase such gear to enjoy recorded music at its finest level, so why compromise!

Cheers, RJ

[AnotherJohnson]

You are fortunate to have good local people, and from private conversation, it is my impressions that yours was one of the last cases where CJ was willing to provide parts.

Since CJ will not cooperate with service shops in the field, providing neither parts nor schematics, it is difficult, especially when they advise that the problem is normal and does not need attention at their facility.

I understand the motivation for not sharing.

But this single power strip solution is bullocks.
If something hums in four different buildings and other monoblocks don’t, CJ really ought to be willing to give them a serious check.

Honestly, this should have been handled on warranty in 2018. They arrived at my house humming on installation. The single power strip forced both amps onto a common ground plane. But it should not have been necessary.

[Joe Appierto]

I haven't purchased a piece of CJ equipment in a dozen years and at that it was used.

As wonderful as CJ's current equipment may be, there is something wrong with their execution of the design The preamps eat tubes for breakfast and if they last a year you're lucky. The ground loop problem continues from when I purchased the Premier 11a more than 20 years ago.

I am coming across as negative, I realize, but other companies such as ARC don't have these problems and perform at a level that's commensurate.

Just my 2¢.

[AnotherJohnson]

The future of CJ is dependent on JF. It’s a big burden.

The vintage gear will continue to please many people as long as it works.

The new gear will find many deep pocket lovers of gold faceplates and repetitious 8s in the mid and far east. And I have no doubt that their ears will tickle too.

Regarding the sonic signature and user interface, it’s good to have choices. I was a fan of CJ sound for 35 years. It can be world class when everything is on track.

But “it just sounds right” does not preclude the idea that other marques may also sound right … or maybe even “righter” in the ears of some.

[admin]

I have had ground loop issues in my system before, but none that could not be relatively easily overcome. CJ has a relatively simple design philosophy when compared to most other manufacturers. Perhaps this is what makes them more prone to have ground loop issues (, maybe not)?

It would be interesting to see a simple component count on these comparative amps and preamps. Not that component count in any way is directly correlated to sound quality (positive or negative).

Ground loops can have so many different causes and each stereo setup is unique. CJ's simplistic circuits may just be more prone to picking up these issues than other designs?

[roberto]

My Pre ET-7V2 with the Classic One Twenty SE is dead silence. I had previously other very good brands, and always had a small signal hiss that you could hear when you were close to the speakers, even using balanced audio cables. Now is fantastic with crystal highs, and a definition that you don't believe it is true what you are hearing. Yesterday came to my place a dear friend who had Levinson, Theta Digital Dac, all top of the line goods. The speakers were JM Labs with the Beryllium tweeter. So, he is accustomed to a high end sound. The first thing he asked was, are you using balanced cables?

Then I said, this is a Conrad Johnson gear, and they do not believe that balanced is necessary for audio system in these days. The signal to noise ratio is beyond -100dB and also being the gear with the philosophy to have the simplest and shortest design, this is what I am listening now.

His face expression said everything. He look at the hook up at the back of my system and saw that was true, no balanced connection and he said: I can't believe this is an unbalanced set up. It is so clean and never heard this quality highs with the silence, no hiss in the behind of the highs. Pure signal, is what it is.

This happened yesterday evening with my dear friend, Fernando Vidales.

Happy listening!

[AnotherJohnson]

My Pre ET-7V2 with the Classic One Twenty SE is dead silence.

Of course you know that the Classic 120 SE is not a pair of monoblocks.

But with that said, even the monoblocks can be silent if everything is right. It’s just hard to get things right.

[Big Dog RJ]

Now that should be the slogan! ..."it's just hard to get things right." ... until it just sounds right!

Yes fully agree 110%! The interesting thing about my experience with CJ is back then, not only was their gear tops but even their service and customer support was truly tops! From where I was located (Colombo), which is nearly on another planet... I could just ring up Ed or LJ and have a technical chat sorting out a few tech issues, done!

But now... good luck!

I'm not saying it's the end of CJ but things have changed drastically and I guess JF is running a business, not charity. So in order to keep churning the numbers, the ART series will sell at SOTA prices based on limited editions. Once these limited editions are sold, that's it! There may be another line to introduce to the lower end category, similar to the Classic series but it won't carry a lot of models, only a handful. Once the numbers have been achieved and all debts are paid and all is well, staff happy and stock has been sold, that's the legacy of CJ unless it will be handed over to someone else worthy... but who?

The CJ vintage line will continue to run, just as long as it works! And this is the sole reason why I never went ahead with the ART purchase... I need something to forward to in the long run, with dedicated support and full customer service, not haphazard service from our local importers... like I said things have changed.

This however doesn't happen with VTL, Manley Labs or ARC, or even McIntosh! Their service base and customer support worldwide is far ahead and still going strong! So as long as I've got access to my local tech and as long as he's got the parts, I'll continue to use my precious CJ gear for as long as I possibly can. After all, he's also getting on in yrs...

Once that line crosses then I guess it's either Pass Labs or Dartzeel with a pair of refurbed Apogee's by Graz. I will definitely end up in this particular scenario. Maintaining ARC tube gear will be too costly for me when I'm retiring or any tube gear for that matter... as far as the CLX's are concerned, I'll be buried with them just as Admin said!

This is just my prediction... I could be wrong but I really don't see things improving much on the CJ front. Just my 50cts take.
Until then, do enjoy those fine tunes!
Woof! RJ

[admin]

I'm sure it's a tough situation with any company. That careful balance of where you put your resources. R&D, production, advertising, support, etc... I admittedly have not had many support requests from CJ, I did have one about a decade ago and had a very positive experience (with Ed, who is of course no longer there).

As for overall quality, I have not had the sense that CJ is now making products that are not of the highest standards. All equipment, regardless of manufacturer can fail. CJ is no exception. When this happens, you want a robust customer service experience to remedy the problem. I wonder if CJ is in that delicate place of being a little too busy to field service calls but not big enough to support a full time service department (with appropriate staff).

Some of the other companies mentioned above (if not all), are significant larger and really in a different category. For god sakes, I see McIntosh advertisement on broadcast TV. Any larger and they are going to be Bose.

Is Jeff making a mistake by trying to keep all service in-house vs relying on distributers more to take care of issues locally? I don't know. I think intellectual property theft hit CJ really hard. The knock-off CJ designs on ebay that can be had for a paltry sums is crazy. 20 or more years ago this was not an issue. It's a big one now.

People tend to keep CJ gear for very long times compared to most other electronics gear. As more and more models are introduced, supporting old gear also becomes more difficult.

Maybe CJ's direction to try and keep everything in-house will backfire? Maybe it won't so that hardware repair standards can be kept high? Time will tell.

[Big Dog RJ]

Yes, good point Admin.

At the end of the day, we all have our preferences and personal favourites, obviously the gear that we put together must bring us the highest level of satisfaction.

Funny point just to mention; although I've had quite a disastrous experience with Quad ESL's, especially the 988, 989, 2905's and 2912's, which were all coming out of China, still to this day my favourite ESL of all time is the Quad 2905. Partnered with CJ gear, it's just pure magic! I could never get any of those Chinese made Quads to work anywhere close to a few months without causing some stupid panel issues... and on some the mains trannies failed. I will never use another Quad coming out of the IAG group but their sound was indeed special.

The Martin Logan's are in a totally different league, and the CLX's for that matter but those Quads just made me melt for endless hours... my listening sessions were way past 4am.

The other panel type speaker that I'm very familiar with and one that performs supremely well with CJ amplification is Apogee. I know that the Apogee's are in very good hands over here with Graz up state, so that will most probably be my retirement panel for sure.

Yes, I'm extremely fortunate to have my local trusted techie, who's worked on and re-engineered various tube designs from VTL to Manley Labs to Golden Tube Audio. He knows my CJ amps inside out and can do diagnostics virtually with his eyes closed! My only concern is that he's getting on in years, and I won't take my amps to anyone else!

Like I said, I'll continue to enjoy them as much as possible and then see what's happening on the other side of the SS horizon. After having owned tube gear since I was a teen, I don't think I'd ever be happy with SS amplification but hopefully the new gen of SS gear will sound warmer and more engaging. I do know that McIntosh sounds warm but it does not engage me. Not just yet... so maybe those big blue meters can hypnotise me again... we'll see.

I do wish Jeff all the best, and would certainly like to see CJ carry on the legacy of Lew & Bill... after all it certainly is audio gear at its finest! It will have quirks and it will have issues along the way but how I see it is such that, if there's a will to fix it then there's a way. I've always found a way! Especially at this level, there are no compromises and I simply won't tolerate any unwanted noises... so far touch wood! It just sounds right!

So here's a big cheers to CJ and Jeff & the team!
WOOF! RJ

[roberto]

Hola Chicos,

I do know that you know this, and being so general, I think it is good to remember this: our ears do not respond from where the signal is coming From if the frequency is below 90Hz. So, a frequency HUM of 60Hz in our room is very confusing. It is very hard to detect from where it is coming from. Our ears are sharp focusing from frequencies starting from 100z and up. Below this frequency is not possible. Even trained ears get confused too.

As a general rule, hum can be produced by the power supply of one component of the system, or could be external by a ground loop. If the hum is coming from the speakers, it is wise to disconnect the input cables of the amp and have a listen. If the hum persists, the power amp is the culprit.

Happy listening!