PV 12 Phase Inverting?

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Bignhot1964
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PV 12 Phase Inverting?

Post by Bignhot1964 »

First I`m New To the CJ family, Thank You for letting me into your CJ Family.

I picked this item up off Ebay , and is on its way to my home and the seller sent me this,
My Question is this true or BS

http://conradjohnson.com/owners-manuals/PV12MAN.pdf

The PV12 is ready to be picked up by FedEx. It has been tested and boxed in Factory PV12 box w/ foam insets. The link above is for the PV12 manual from CJ. PV12 is phase inverting, so the easiest way to deal is switch the +/- wires at the amp if bi-wired to speakers or at the speakers, reverse +/- for right and left speakers.

If you are not familiar, call CJ or send an email. Its best to speak to them as you'll likely get a tech and he/she can answer all questions.

I replied whats the advantage?

Second Email
I don't understand your question. Do you mean why do they do it that way?

It is an attempt and correct thinking that by each voltage stage does one inversion, so if you had two stages then they cancel each other out. Each voltage stage added moves the listener further away from the true sound. Much of CJ stuff is single stage, so there fore the second stage that would cancel out the first inversion is not there to do so, and therefore you do the inversion at the speaker or speaker connection on back of the amp. Here is their explanation and a link to more information.

"Each active voltage gain stage in a circuit inverts phase once. In pursuit of ultimate purity in music reproduction, recent conrad-johnson preamplifiers have been designed for the absolute minimum number of gain stages—one.
One stage, one inversion, hence these components invert phase. "

If you are not use to CJ stuff then it is odd, but trust that the experience of a fuller and more dimensional sound stage is had when you invert when necessary. Most of my CJ amps invert, so when both amp and Pre invert they cancel the inversion out and you wire as normally would. Welcome to the high end of CJ. It doesn't hurt anything. It is necessary to achieve complete sound nirvana w/ this thing.
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Re: PV 12 Phase Inverting?

Post by admin »

Yes, the PV12 is phase inverting. If you have no other phase inverting components in your system then the simplest thing to do is reveres the speaker wire positive/negative connections at either the amp or the speaker.
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Re: PV 12 Phase Inverting?

Post by roberto »

Hola Bignhot1964. The most convincing statement and answer about the phase is, because it is the shortest way in the path. This means, less distortion and better sound. Phase inverting is not a problem. Besides the 50% of the recordings are done with phase inverting. Philips, Sony, Deutsche Grammophon, their recordings have phase invert, to name a few. The recording companies believe that absolute phase is very hard to detect. And the recording Industry leaves this possibility open. On systems like ours, the phase is easy to detect.
When you are out of phase, the vocals or the main instrument appears to the listener too big, and also lacking the sense of 3D. A reason why some DACs or hi res software brings with a check mark to keep the phase correct. If the recording comes with phase inverted, the software will detect it and it invert the phase for you.
Conrad Johnson, in persuade to bring the best of the overall sound, some preamps and power amps models have the phase inverted. As our ADMIN answer you, that´s the right way to have your system in phase.

Happy listening!
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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jahatl513
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Re: PV 12 Phase Inverting?

Post by jahatl513 »

It sounds like you have the right answers and the seller was not BS'ing you. With the actual literature link to PV12 you do see it on page 6 that it says phase inverting and then how to handle it. Good Luck!
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Re: PV 12 Phase Inverting?

Post by dtsbill »

Hi Everyone I am a new member to this owners club had my system for 8 to 9 years now which is a pre met 1 and amp 150 , I live in the UK and imported them both at very serious cost, the sound from both is just excellent. My only problem I have is valve noise and hum from the met 1 when connected to the met 150 which also have a not nice thud when powering off , over the years done everything to try and resolve these issues with no luck, amp is quite when ground is disconnected but when connected to preamp it comes back (even with the earth disconnected from that too) ,as soon as rca cables are linked between the two it's back again.
Would love to send it back for remedy but cost make that out of the question.
Regards to everyone Billy
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Re: PV 12 Phase Inverting?

Post by roberto »

Hola dtsbill,

It looks that you have a ground loop problem. You have to find from where it is coming. The first thing to do, is just connect your pream to your amp, but no other components connected. Turn the both on a have a listen. If you have a hum, then to find which is, turn both again off, and disconnect the preamp from the amp. Leave only the amp with the speakers and turn it on. If you have a hum, then the culprit is the amp. If you have no hum, your amp is OK. Then change the RCAs cables and connect again the preamp to the amp and turn both on. If you have a hum, then it looks that the preamp is the problem. If you have no hum with both connected, then bring the volume of the preamp down, and connect the cd player only. If you have hum, the cd player is. If you are using a DVD player, the ground loop is coming from the TV. Disconnect the TV antenna and have a listen. If you do not have any hum with all your components already connected, then what you need is an antenna ground suppressor. You can buy this device at amazon. It goes from the antenna to this device, and from this device to the TV antenna input.
When you power off your system, first turn off the power amp and wait 30 seconds, then power off all the other components. The sound when you power off is when the capacitors are discharge and will not harm your amp or your speakers, but it is annoying.
Happy listening!
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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Re: PV 12 Phase Inverting?

Post by ajf75 »

back on topic of OP...Roberto sums up the situation nicely. The recording companies belief that it is unnoticable or unimportant to 99.9% is true. But we in this hobby are the 0.1%. Some audiophile recordings do specify that they carefully maintained proper phase - so finding one of those would be good for testing if interested. Also Stereophile has, or had, test CD's for determining this. From my experience its been pretty easy to tell which way 'just sounds more right' with a particular recording when taking the time to perform an A-B-A test. But as mentioned, no matter which way you go, it wont be correct with all recordings.

Really wish CJ pre-amps had a phase selector button! but then of course the added circuitry conundrum.
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Re: PV 12 Phase Inverting?

Post by Big Dog RJ »

With CJ amplification and their simple circuit designs, plus keeping gain stage to a minimum, very correctly pointed out as previous replies, the only one gain stage CJ incorporates changes the phase on the preamp outputs.

However, this change of phase is actually "preserving the phase" and not altering it in any way.
Therefore, in order to maintain relative phase the user can change one speaker lead at the speaker end.

In order to maintain "absolute phase" both channels must in inverted at the speaker end. Also, I believe the difference is quite apparent, vocals are centered, soundstage is more focused and the width & depth is clearer. The most significant difference is in strings, the plucking is razor sharp and the whole presentation feels fuller.

In a system out of phase, I feel the reproduction is lost, it doesn't have that definition and no focus in vocals or the soundstage, and strings are loose sounding not tight and fast as they ought to be.

CJ explains this quite clearly in their owners manuals, plus they include a separate page on phase inversion in red color, so you can't miss it!

Just my 50cts worth. Cheers and enjoy your music;
RJ
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Re: PV 12 Phase Inverting?

Post by roberto »

Yup, I do belong to the absolute right phase. Right now, I am listening to digital only. With my Audirvana Plus when I listen to ITunes, and using Core Audio, I have the settings to keep the polarity of the absolute phase right. Also , when I use ASIO, with HQPlayer, I have the same setting, keeping absolute phase right.

When you have a recording where everything is too big, you are with the phase inverted. Change the absolute phase, and you will get the right size of the instruments and vocals at the stage . Easy to tell with vocals too.

I love to have the phase "right". I have to confess that my ears are a musician ears. These ears of mine, just love to have fun to listen to the musician(s) having the fun playing their instruments and singing along. Music is to me, the most pureness for the pleasure to listen to these great musicians! And having Conrad Johnson is a gift, a prize, an award to them. A big priceless jewel.

In sum, we are capable to listen it. And it is not too difficult to hear it. Again, when the voices are too big, then you are usually out of absolute phase, Just invert the polarity on both speakers, and you can tell it right away. The problem is that sometimes, one microphone is out of phase with the other mics on the recording, So, here is almost impossible to have the absolute phase correct. Just choose the one you liked most and keep it this way.

On the other hand, just relax and enjoy the wonderful musician(s) that are playing for us at the recordings. I think that because we love to listen with this marvelous quality of sound reproduction, we forget the fun that is to enjoy these guys playing for us. Right now I am listening to this fantastic trumpet player Mr. Chris Botti Live with Orchestra and Special Guests. Wow, what a fantastic recording. All the musicians are doing a fantastic job, and you can tell the fun that they are having playing along with Chris. In the track " When I fall in love" The drummer, the bass player, the guitar player, the strings section, the pianist, the whole band is...one.

Happy listening!
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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Re: PV 12 Phase Inverting?

Post by Big Dog RJ »

Hey Roberto,
You caught my attention - Chris Botti!

I have every album of his, all on CD & sacd. I've also seen him play live, he's marvelous!
Just some info, he was part of the group Sting, and played trumpet with Sting. After many years, he decided to go solo. I have a very special album of both Chris Botti & Sting playing together, it's just superb!

Although my favorites are Miles Davis and Chet Baker, Chris Botti is in a different class. His classical playing is so emotional and engaging, it's unbelievable!

Watching this guy live is like a phantom spirit, he can play soft, softer than a whisper and all of a sudden accelerate without any strain to such powerful notes, I tend to wonder how he doesn't run out of breath...

On the CLX's this is something truly spectacular!
Every album of his is fantastic, he's never got an average album, they're all top notch.
Cheers mate, and have a good one with Chris Botti
RJ
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Re: PV 12 Phase Inverting?

Post by roberto »

Hola RJ,

I do not want to hi-jack the thread, but have you listen to this fantastic trumpet player Rick Braun? The first time that I listened to him playing was with Brian Bromberg (one of my bass favorite player) playing flugelhorn.

With this recording by Brian Bromberg: Downright Upright, you can listen the phase very easy. The size of the bass and the flugelhorn changes dramatically. Where everything snaps with the right size, there is your right phase, not having the instruments too big.

Happy listening!
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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Re: PV 12 Phase Inverting?

Post by Big Dog RJ »

Yes mate, totally agree.
Getting back to phase inversion - as per the OP; when the system is in absolute phase, everything fits nicely into place, and it is definitely noticeable.

I must admit though, at times this can be bit confusing. Especially when recordings are not in total phase to begin with... I also remember at the time of using one of CJ's CD players, DV2B, it actually had a phase switch /button on the front panel, and this helped tremendously.
It's a shame that model is no longer in production, and CJ does not offer anything new on digital playback either.

Swapping the speaker leads was the easiest and most convenient thing to do in order to achieve absolute phase, and that is of course if only one component in the system is phase inverting. Adding another phase inversion brings this to an even number.
As long as the total number of phase inversions is Zero or 2 (being an even number) then absolute phase can be maintained.

As I mentioned before, the owner's manual clearly addresses this topic and how the user should proceed.

Referring to the OP, I trust that the pv12 is working fine and the speaker leads have been reversed at its terminals. Do let us know how your system is sounding so far...
All the best and have a good one, RJ
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Re: PV 12 Phase Inverting?

Post by dtsbill »

Hi Rorberto Thank you very much for the response from yourself, I found that very helpful, amp is quite when just connected to speakers hum does come back only when preamp is connected to amp ,I have tried several rca,'s , which does not improve the hum, both units are connected to the same mains outlet so I do not think it's a ground loop issue , and earth to both have been disconnected.
I do think the culprit is the preamp, also tried new valves . Conrad Johnson recommended rca,'s with two centre conducters in manual and braided screening only connected at one end, I do not know of any like that unless I miss understand what they mean .
Once again many thanks for your help Roberto.
System -met 1 met 150 oppor 205 speakers dunlavys front surrounds and back .
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Re: PV 12 Phase Inverting?

Post by admin »

You can also try an rca to rca ground loop isolator for diagnostic purposes. They can be bought for under $10 and I have found them to be helpful in finding the culprit in ground loop issues. I've used them before in my system when I had a ground loop issue.
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Re: PV 12 Phase Inverting?

Post by roberto »

Hola DTSBILL.

Your hum is coming from the Oppo. Just disconnect the HDMI that it is going to the TV, Its a ground loop from your TV Antenna. Disconnect the TV antenna or the box that you have with your tv and you will see that hum is gone. Its the difference of ground with your house and the ground of the electric post near your house.

You need an antenna ground loop suppressor.

Happy listening!

Do not hi-jack this thread with things that does not belongs to phase. PM please. I will respond to you with much pleasure.
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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