Problem with VPI Balanced Junction box

[Prestige Worldwide]

After purchasing an Ayre P5xe I decided to upgrade my Aries II to add a balanced junction box (with Nordost Valhalla wiring). After installing it, I noticed that my Accuphase A50 was showing my right channel outputting more watts then my left (it has a digital readout). As I increased the volume, the difference grew as well (from 10-50 peak watts), and it became noticeable to my hearing too. I swapped out different cables, even borrowed my dealer's P5xe, but the problem remained (when I switched back to the rca box, there was no issue).

Well, my dealer just provided me with a second junction box, and after installing it, I've noticed the same problem. I still get more power out of my right channel compared to my left (if I swap my left and right outputs, the problem swaps as well). I even used my decibel meter just to see if my ears really could confirm the difference, and sure enough it showed between a 2-5 max decibel difference depending on how loud I played it.

Has anyone else experienced this issue with a VPI balanced junction box?

[Prestige Worldwide]

Thought I'd update this thread in case anyone else had a similar problem.

Never could quite figure out what the problem was, but after talking with VPI we both agreed that there clearly was a phase issue plaguing my system. Whether the root of the problem was with the junction box is unclear, but I solved it using a custom made Acoustic Zen phono cable based on specs provided by Ayre (which I found researching my P5xe phono pre).

For those who have balanced phono inputs on their pre, Ayre created a cable with rca terminations that carries the hot signal and inverted signal separately (the inverted is carried through the shield on the rca end). Ayre offers a cable of its own or allows you to send its schematics if you prefer to have them custom made elsewhere (another reason why Ayre rocks as a company). The schematics can be found here: Ayre Acoustics Phono Cables

I spoke with Mike at VPI who acknowledged that, since a TT creates an inherently balanced signal, making a balanced cable with rca plugs was entirely possible. So I sent the schematics to Robert at Acoustic Zen (I use AZ cables throughout my system). Working off the below "dual cable" schematic, Robert made me a Silver Reference II phono cable.



Here is the end result:









I highly recommend this for anyone who has balanced phono connects but no way of connecting xlr cables to their phono.

Regards,

David

[jdandy]

David......Way to go. Problem solved. It was good of you to post the schematic here.

[JohnA]

are you sure there want something wrong with the balanced cable you were using?
i have had this happen to me where the difference between left and right channel was around 6dB
ended up been a faulty balanced lead. Swapped cables over and problem fixed.

[Prestige Worldwide]

Originally Posted by JohnA

are you sure there want something wrong with the balanced cable you were using?
i have had this happen to me where the difference between left and right channel was around 6dB
ended up been a faulty balanced lead. Swapped cables over and problem fixed.

Yes, I'm sure it wasn't the cable. As I described in my initial post, I tried different ones to no avail. In fact, I hauled the entire table to my dealer and played it on his Ayre system. He heard the same thing that I did.

[JohnA]

d'oh

should have read your original post better.
It is an interesting problem you were faced with there.
The only times i ever came across any issues with balanced setups was if the cables were faulty, or the balanced wiring on the 2 components was different.
I know marantz and melody use different balanced wiring to the normal.

Glad to read your problem was solved though.
Would be interesting to hear from others though who also used the balanced junction box.
I have been thinking of doing it to my HRX but dont decided against it

[Prestige Worldwide]

Originally Posted by JohnA

The only times i ever came across any issues with balanced setups was if the cables were faulty, or the balanced wiring on the 2 components was different.

You've nailed it with the wiring. My suspicion all along was that there was an issue with my amp. My Accuphase is wired the opposite of most conventional balanced designs. However, I was running single ended into the amp at the time, so I couldn't quite understand whether the Accuphase's different balanced circuitry was even playing a role. I know, however, when I went single ended from the source my problems went away. Nevertheless, I also ordered a custom balanced cable that would work with my Accuphase. With that cable and the special balanced phono cable, all my phase issues went away.

Still, with the design offered by Ayre, I don't really know if there's a reason to even get the balanced junction box. I'd save the $300 and put it toward the cable, which you'll need anyway if you decide to switch to a balanced connection.