Problem with 50 Hz hum

[Konforti]

.Hi all, sorry for posting in English. I am new to Israel and have a terrible problem of hum in the mains.

Am I the only one with this problem?

My source is a Denom AV11, preamp Audiopax Model 7 and power V8, both made in Brazil with toroids certified for 50 Hz.

Please help, the noise floor is way too high and umpleasant!

todaraba,
Aharon: Confused:

 

[רונן ש]

Hi Aharon,
don't worry, there are excellent professional folks here that will try to help.
And sorry for the orientation of the text, it seems that this web site doesn't support left-to-right typing quite well.

The 50Hz humm sounds like a typical groundloop issue. Let's try find where it is, the easy way.

1. Does the noise appear on both loudspeakers?
2. Please disconnect the preamplifier from the amplifier. Turn the amplifier on. Is the noise still there?
3. If the noise disappeared in 2, please reconnect the preamplifier to the amplifier, but leave the CD player disconnected. See what happens to the noise.

let's begin with this and try move forwards.

 

[חומוס]

Is it possible you're using a 110-220 converter?

Sometimes that's one of the side affects.

 

[Konforti]

Hi Ronen, thanks for the warm welcome. Both the power amp and preamp are the Brazilian made for export, so they 'll work in 240vac / 50 Hz. 1. Hum is present on Both ChannelsI 2. It disappears (from the speakers) When I disconnect the preamp 2.1 -, lly ".The power amp toroid Keeps buzzing" physica, lly "and its noise is higher than the noise on the speakers . 3. Either in or out, the CD player does not add Any hum. Thanks for your help, this noise floor is very loud and nasty. Aharon

 

[רונן ש]

Ok Aharon, this is a progress!

It seems that the Amplifier is 'clean' of the guilt of 50Hz humm.
the mechanical buzz is understood, quite nasty I know, but this is a separate issue. Probably higher quality transformers wouldn't create such a loud buzz, and there's also a possibility of tightening screws and reduce that sound.
let's deal with it afterwards.

So it's somewhere in the preamp region.

experiment 1: can you take the CD-preamp interconnect cable, and use it to connect the pream to the amplifier? Perhaps the mulfunctioning element is in the cable.
exmeriment / question no. 2: what can you tell about the preamp's power cord? Has it been serviced recently? Have you (or sombody else) replaced the original plug with an Israely one?

I'm asking all that because if -by mistake - the preamp is grounded, and the amp itself is also grounded, we have a very typical groundloop here.

 

[שניצל]

רונן ,מכיוון שאתה שמה בענייני אנגלית ,למה שלא תאמר לו לנתק את כל האדמות מכל המכשירים למעט אחד , הרעש המכני מהטרנספורמטורים נובע אולי מDC ברשת ,במסגרת "הסבר פניך לתייר מוכן להלוות לו פילטר מיוחד שיבטל לו התופעה ,מקווה שגר קרוב .
תרגם לו בבקשה ,ותאמר לו שאנחנו נהיה אלופי העולם בכדורגל שהילדים המאומצים מברזיל יגדלו.

 

[NStudio-Hiend]

רונן ,מכיוון שאתה שמה בענייני אנגלית ,למה שלא תאמר לו לנתק את כל האדמות מכל המכשירים למעט אחד , הרעש המכני מהטרנספורמטורים נובע אולי מDC ברשת ,במסגרת "הסבר פניך לתייר מוכן להלוות לו פילטר מיוחד שיבטל לו התופעה ,מקווה שגר קרוב .
תרגם לו בבקשה ,ותאמר לו שאנחנו נהיה אלופי העולם בכדורגל שהילדים המאומצים מברזיל יגדלו.

לא הבנתי ,רופא ללא אנגלית :בהלם:

 

[שניצל]

למדתי ב"אנא גאח"

 

[NStudio-Hiend]

למדתי ב"אנא גאח"

????? לא חושב .
אפשר לבזבז כמה אגורות על שיחה איתי ? לא ?

 

[רונן ש]

לא הבנתי ,רופא ללא אנגלית :בהלם:

עד כמה שהבנתי, אנשים אצלו אכן פותחים הרבה את הפה, אבל אומרים מעט מאד.
ולא ממש משנה מה הם רוצים להגיד...

 

[רונן ש]

רונן ,מכיוון שאתה שמה בענייני אנגלית ,למה שלא תאמר לו לנתק את כל האדמות מכל המכשירים למעט אחד , הרעש המכני מהטרנספורמטורים נובע אולי מDC ברשת ,במסגרת "הסבר פניך לתייר מוכן להלוות לו פילטר מיוחד שיבטל לו התופעה ,מקווה שגר קרוב .
תרגם לו בבקשה ,ותאמר לו שאנחנו נהיה אלופי העולם בכדורגל שהילדים המאומצים מברזיל יגדלו.

שניצל אתה צודק בענייני האדמות, מה שאני מנסה לברר זה אם זה עבד טוב בברזיל, ונהיה זבל עופות פה.
או אם טכנאי 'מוכשר' חיבר לו אדמה לקדם מגבר 'שיהיה'. יש כאלה תופעות.

ואפשרות אחרת שהתנתק סיכוך בתוך ה-interconnect.

תרגיל אינטלקטואלי, לנחש מרחוק בלי לנגוע בציוד עצמו...

 

[רונן ש]

Hi again Aharon,

Assuming that we WILL find the reason for the electrical hum and solve it:

One of the leading experts here in the forum (nickname Schnizel, very well known in this part of the Middle East...) suggests that the reason for the mechanical buzz could be un-ballanced AC power, which can be seen as a DC level.
This can be eliminated by using a dedicated isolating transformer between the power line and the amp.
It gets even better, since he is willing to lend you such a transformer for experiments.

Can you tell us where you live? Perhaps one of the knowldgeable members can coordinate a short visit at your place, trying to solve these issues.

 

[Konforti]

Hi Ronen, thank you for Following up with me.
Yanking two earthing prongs Leaving just the power earthed Minimized the hum "on the speakers". Now it is like 5% of the kitchen refrigerator's usual noise level (you know what I mean).
I feel honored with the offer of a loaner Isolating transformer. I live in Ramle, but I need a couple days to re-install the window iron protection (which went out to allow a piano into this third-floor small apartment ... Crane and all. I MUST be crazy) before we arrange this visit.
Ronen, in Defence of my Brazilian friends and Rightful high-end manufacturers, here are Their links: http://www.audiopax.com/ (Portuguese / english) http://www.sunriselab.com.br/ ( only Portuguese - use Google+ and have some laughs) These are serious people, Beside being my friends.
Maybe I am a pioneer for their products abroad, but problems have a solution. Pessimism Though is incurable. Thanks again to you and Mr. Schnitzel (I saw there is also a Hummus. Should I have chosen "melafefon" as a popular nickname?

 

[רונן ש]

Hi Aharon,
yes it seems that you had a ground loop through the earthing prongs of the power cables.
what you did was right - the amplifier should be grounded via its power cord, while the other members of the chain should be grounded via the interconnect cables' shields.
just make sure that these interconnects are alwaws connected - as a safety precaution.

regarding your friends from Audiopax - hey, this looks interesting!
I'm personally far from being a 'tube sound' fan, but there's a raging community of audiophiles here in the holy land that would love to know more.
and if the price-performance combo is appealing - this can be an interesting market.

Why won't you contact one of the local hi-end audio distributors? A fast commercial contact can be created, followed by a set of products being shipped over here for demonstrations and reviews.
can be interesting.

regarding you nickname - since few leading persons in this forum call themselves YEMENITES - perhaps a good nickname should be: Schoog

 

[שניצל]

הנה - זה מה שהוא צריך !
http://www.i-kwart.eu/index.php/showroom/ps-audio/perfectwave-power-plant-5-ps-audio-3.html
מוזמן לבוא לקחת ולנסות !

 

[רונן ש]

הנה - זה מה שהוא צריך !
http://www.i-kwart.eu/index.php/showroom/ps-audio/perfectwave-power-plant-5-ps-audio-3.html
מוזמן לבוא לקחת ולנסות !

ענק אתה!
לפי דבריו הוא צריך עוד זמן להתארגן בדירה..

ומה שאמרת בזמנו - להציף את המכשירים מארקות - זה בדיוק מה שהיה צריך.

 

[Konforti]

Ronen, I use Van den Hul The First and The Second interconnects, which are carbon fiber and factory sealed. That makes the issue of suspending the ground on the interconnects moot. I hope the PS Audio Humbuster does the trick. The capacitors are oversized, so I do not expect compression of dynamics. The 'features' state That it "does not fix ground loop Hums" But I the think we have That covered by now, thank you very much!
A picture of the power cables Could I own and never use "Baaretz".
You can see a Furutech two-outlet over the laptop. I think of wiring it without any ground, and use it for the preamp and the source.

Talk to you guys soon.

 

[Konforti]

OTE = Schnitzel; 261 330] is - That's what he needs Come take a try! [/ QUOTE] Generous gibor! Todaraba Schnitzel, ata ben-adam tov!

 

[Konforti]

[QUOTE = "Ronen that, post: 260 861, member: 13254"] Hi again Aharon,

Assuming that we WILL find the reason for the electrical hum and solve it:

One of the pronounced pronounced leading experts here in the forum (nickname Schnizel , very well known in this part of the Middle East ...) Suggests That the reason for the mechanical buzz Could be un-Ballanced AC power, Which can be seen as a DC level.
This can be eliminated by using a dedicated isolating transformer between the power line and the amp.
It gets even better, since he is willing to lend you such a transformer for experiments.

Can you tell us where you live? Perhaps one of the knowldgeable members can coordinate a short visit at your place, trying to solve these issues. [/ QUOTE]

Dear Ronen,
My humble hut is ready to receive the visit of a good-hearted person with Schnitzel's loaner isolating transformer.

I am sending you a private message with my address.
Thank you and Schnitzel for your help.

Aharon