Building a Balanced Power System

[Speedskater]

I wasn't aware RFI would cause a buzz in a balanced power transformer?

No it won't cause a mechanical buzz in a power transformer. But I don't think that an functional plasma TV could cause enough of a DC offset to bother any good power transformer.

 

Questions?

a] Is the TV plugged into the same AC power outlet (or transformer outlet as the hi-fi)?

b] Does the TV have a satellite or cable TV input cable?

c] Will the system work correctly with the transformers removed from the hook-up?

 

As for troubleshooting, state at page 100 of this Bill Whitlock paper.

And build a John Windt "Hummer".

 

"An Overview of Audio System Grounding and Interfacing"

by

Bill Whitlock, President

Jensen Transformers, Inc.

 

http://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

[ilok]

Transformer sound is unavoidable, can you relocate the transformer to another room and run long power cable?

 

Otherwise, the Equitech Q is the quietest transformer I've came across so far.

[liquidsmoke]

Speedskater: 'one and a half' user shares your opinion somewhat I think, as he suggests in his info about the di/dt power draw characteristics.

 

In answer to your question; I have tested the plasma TV plugged in a variety of locations. Without the balanced supply, the plasma causes ground issues (humming) from speakers. If I remove the ground pin from the plasma all is OK. When using the balanced supply with everything plugged into it, the hum is gone. No hum even with ground connected on the plasma. However I am getting these annoying and quite loud at times, intermittent buzzing (notice the word buzzing; not really a hum. More intrusive and metallic sounding. So even more annoying than a hum) coming from the transformer in the balanced supply when the plasma is turned on.

 

Aerial feed disconnect was the first thing I tried. There is also an inline galvanic isolator on the aerial cable now for good measure.

 

I am planning on trying out a DC blocker. Its relatively cheap and should turn up in a week or 2. So I will report back my findings. Hopefully it is DC, but I fear that it isn't.

[One and a half]

Transformer sound is unavoidable, can you relocate the transformer to another room and run long power cable?

 

Otherwise, the Equitech Q is the quietest transformer I've came across so far.

 

Yes, even the Model Q can rattle. It's physics. Interesting about removing the earth on the plasma and the hum disappearing. The hum and the metallic rattle in the balanced transformer are not related, so different methods required for the two problems.

 

The Jensen transformers are very good, and work well to get rid of the hum, the analysis takes a bit of working out, but if the guidelines presented in the Jensen papers are followed the hum will go.

[One and a half]

Speedskater: 'one and a half' user shares your opinion somewhat I think, as he suggests in his info about the di/dt power draw characteristics.

 

In answer to your question; I have tested the plasma TV plugged in a variety of locations. Without the balanced supply, the plasma causes ground issues (humming) from speakers. If I remove the ground pin from the plasma all is OK. When using the balanced supply with everything plugged into it, the hum is gone. No hum even with ground connected on the plasma. However I am getting these annoying and quite loud at times, intermittent buzzing (notice the word buzzing; not really a hum. More intrusive and metallic sounding. So even more annoying than a hum) coming from the transformer in the balanced supply when the plasma is turned on.

 

Aerial feed disconnect was the first thing I tried. There is also an inline galvanic isolator on the aerial cable now for good measure.

 

I am planning on trying out a DC blocker. Its relatively cheap and should turn up in a week or 2. So I will report back my findings. Hopefully it is DC, but I fear that it isn't.

 

Please fill us in on the results.

[liquidsmoke]

Ok, so my dc blocker arrived today. Arpagon from diy audio built me the blocker to a high spec which could be placed anywhere in my system (in theory). 27,000mf caps were used I believe. It's very nicely made and in a nice metal box too! Anyway I've just been having a play and it does seem to have helped. However you have to be careful where it's placed.

 

firstly I tried to place it between the wall socket and the airlink. All my equipment is Hanging off the airlink now including the plasma. Buzz still there!

 

secondly I placed the dc blocker in between the airlink and all the equipment in the rack. Buzz gone! Great! TV picture seems good. Then I tried to listen to my Hifi for music. I listened to a couple of fav tracks... Bass sounded muddy and horribly. Very restrained and undynamic. Hmm...I thought maybe I was hearing things and perhaps I wasn't in the mood...

 

lastly I tried putting the blocker just in front of the plasma... Buzz still gone. Good! Music...back to how it sounded before.

 

So, I'm happy I guess. Seems like this plasma must be kicking out a lot of dc intermittently. I probably didn't need to overspec the blocker so much but at least I now could use it on anything pretty much down the line if needed.

[ilok]

What brand of tv is this? So I know to avoid them in the future. Are you sure your tv is not defective?

[One and a half]

What brand of tv is this? So I know to avoid them in the future. Are you sure your tv is not defective?

 

This would be fairly typical of any flatscreen, since they utilise similar technologies. Thanks liquidsmoke for the update, one more to right into the book of knowledge

 

Interesting to hear that the DC blocker when used on the airlink feeds made the bass muddy. I found this as well using a Monster line conditioner on the output of the Equitech balanced transformer. Could be the filtering used messes up and creates ringing or other resonances which affect bass. That's where the power is for music...

[liquidsmoke]

Yeah it was uncanny how bad it sounded with everything going through the blocker!

 

A slightly update to my previous is that I am still getting a bit of Buzz (with blocker just before TV), but it's not as bad as before. So I'm happy-ish

[Jabs1542]

Yeah it was uncanny how bad it sounded with everything going through the blocker!

 

A slightly update to my previous is that I am still getting a bit of Buzz (with blocker just before TV), but it's not as bad as before. So I'm happy-ish

 

Have you unplugged the plasma for a while and validated that it is the single culprit in your bus dilemma?

 

This is interesting, though I handed the plasma down years ago to my college bound oldest, I do have an LCD mounted right above my gear. Does anyone suspect this is a byproduct of the plasma technology (meaning all plasmas will have this) or is it possibly just a power supply, which probably has to work pretty hard, going bad?

[liquidsmoke]

It's a panasonic. From what I read it is part and parcel of the plasma technology. They use (sometimes multiple) switchmode psus to fire electrons around at high voltages. I don't think it's the TV going bad or anything. These plasmas PSUs are actually audible to the ear themselves when they are on! So scary to think what they dump onto the mains.

 

My Yamaha AVR does cause the airlink to buzz a small amount when it's on, by barely noticable. None of my other kit causes buzz:

arcam alpha 10

arcam alpha 10p

popcorn hour a-400

arcam alpha CD

musical fidelity dac + v-link

linear psu for popcorn hour and v-link

bluray player

mac mini

netgear switch

[The Computer Audiophile]

Good thread. I just listened to a balanced power system and heard great benefits. My Google searching led me here :~)

[One and a half]

Good thread. I just listened to a balanced power system and heard great benefits. My Google searching led me here :~)

 

Thing is the concepts are true today as they were in 2015 or earlier Much the same can't be said for OS and software!

[brettMc]

Hi All,

 

...first post here.  Um, who wants to build me one of these? Say closer to 3000w?

 

I mean I am pretty certain I could do it, but really would rather have a pro take it on so I didn't doubt the unit (and myself) every time I fipped the switch.

 

lemmeknow.

 

thanks!

 

-brett 

[brettMc]

On 3/31/2015 at 0:53 PM, liquidsmoke said:

Ok, so my dc blocker arrived today. Arpagon from diy audio built me the blocker to a high spec which could be placed anywhere in my system (in theory). 27,000mf caps were used I believe. It's very nicely made and in a nice metal box too! Anyway I've just been having a play and it does seem to have helped. However you have to be careful where it's placed.

 

firstly I tried to place it between the wall socket and the airlink. All my equipment is Hanging off the airlink now including the plasma. Buzz still there!

 

secondly I placed the dc blocker in between the airlink and all the equipment in the rack. Buzz gone! Great! TV picture seems good. Then I tried to listen to my Hifi for music. I listened to a couple of fav tracks... Bass sounded muddy and horribly. Very restrained and undynamic. Hmm...I thought maybe I was hearing things and perhaps I wasn't in the mood...

 

lastly I tried putting the blocker just in front of the plasma... Buzz still gone. Good! Music...back to how it sounded before.

 

So, I'm happy I guess. Seems like this plasma must be kicking out a lot of dc intermittently. I probably didn't need to overspec the blocker so much but at least I now could use it on anything pretty much down the line if needed.

Panasonic plasmas audibly buzz....at least the one in my home does. Especially if the screen needs to produce white or a whole white screen.  Thankfully I do no serious listening in my living room.