[mr_superlove]

Hey all, I'm looking for some opinions before I spend more money.

My vinyl rig is Music Hall MMF-5 > RSA XR-2 > RSA HR-2 > AKG K701

One thing that bothers me a tad is the relatively high noise floor I experience with it.

I've tried to find the source of constant buzz/hum and I've ruled out the HR-2. I can hook up a budget DVD player to it alone and have virtual silence when nothing is playing.

With the TT/phono stage added back in, I can effect the noise floor to some degree by messing with the TT ground wire going into the XR-2. But I can only get it so low. The buzz/hum is present regardless of whether or not the TT is on.

What would be your course of action to take to find the source of it? One thing I've suspected is a very, very cheap power cable I got for the XR-2 ($5 computer power cable.) But, the HR-2 has the same type of power cable and like I said, with the phono stage/TT removed all is quiet. Would an expensive power cable help a lot? a little?

I appreciate your help.

 

[lini]

You might need to define the high in "high noise floor". Is the noise just there, when you turn the volume to very high settings (and then only really audible during pauses, while it's completely drowned out, when there's music playing in usual recording levels...), i.e. is it just a tad higher than practically silent backgound you get with a cd/dvd player connected to the headphone amp? Or is the buzz/hum also present and would seem rather high even in low volume settings? If it's the former, that's pretty normal - if it's the latter, you probably have some grounding issue, or maybe also an emi issue...

Did you already try what happens, when you just connect the phono stage (i.e. without the turntable attached to it)?

Greetings from Munich!

Manfred / lini

 

[mr_superlove]

I appreciate the reply. I'm at work and will have to answer these a little later in the day.

I believe it is the latter (noise apparent and consistent regardless of volume level.)

What is EMI?

 

[mr_superlove]

Quote:

Originally Posted by mr_superlove /img/forum/go_quote.gif What is EMI?

Wait it's electromagnetic intereference, right?

Would this potentially be because of the cheap power cable?

 

[jjhatfield]

Quote:

Originally Posted by mr_superlove /img/forum/go_quote.gif I've tried to find the source of constant buzz/hum and I've ruled out the HR-2

Sounds like what you have is a ground loop hum. I had one of these as well when I first setup my TT. Really annoying, but it can be fixed!

The most important thing I did to solve my ground loop hum was plug ALL of my audio gear into the same wall socket, and have ONLY audio gear plugged into the socket. Previously I had my PPX3 in another socket, and some of my computer stuff plugged into the same surge protector as my other audio stuff. Once I moved my computer to one wall and socket, and moved all my audio stuff to the opposite wall and socket, the hum all but disappeared. Chances are it won't completely disappear, but it disappeared to an acceptable level (meaning I had to be playing no music with the volume maxed to hear any hum at all).

On another note, even that hum went away completely when I installed a Brick Wall Audio Surge Protector. This was not the reason I purchased the Brick Wall, since really the hum didn't bother me, but I was delighted to find the complete absence of hum, even at max volume, a pleasant side effect.

 

[Thermionic]

Low-level hum in a record playing setup was part of the ‘fun’ of what people now call ‘vinyl’. For those of us used only to the silent background of the CD player it might be a bit of a shock getting used to playing records. That’s not to say that a top flight turntable system playing top condition Lps won’t be almost silent, but there are all sorts of opportunities for various noises from local digital electronics, radio stations and mains transformers to creep in. My own system still has a very low level hum (fortunately masked by grove noise), and it often depends on how far you are willing to go before it becomes not worth bothering with any more.

As jjhatfield suggests you probably have an earth loop. This can happen when you are using pairs of screened cables into sensitive amplifiers. What happens is that the outer left and right screens of the cables form an electrical loop with the chassis of the turntable and the amplifier that allow induced currents from mains transformers or electric motors in the vicinity to circulate in the leads. These currents are coupled to the signal wires by the capacitance of their insulation, and you can get a nice low-level mains hum. To get round this I / we used to make up pickup/turntable leads with just one channel having the screens connected at each end, the other channel screen just being connected at the amplifier end (which breaks the induction circuit but keeps the wire screened). You might try pulling out one of the phonos plugged into the TT until the outer contacts just disconnect (if the centre pin is long enough to remain connected) and see if this makes things any better.

Another thing I have found is that the mains ’polarity’ can effect the amount of hum present. If you are using a 2 pin mains plug for the TT try turning it over (I am a bit in the dark here in the UK, perhaps 3 pin mains over there is standard now), might change things for the better. I also have a little Technics parallel tracking TT with a 2 pin mains input and the polarity of this plug affects the overall hum level.

Hum and turntables is a black art, but you can count yourself lucky that you are not picking up some long wave radio station as well!

Just a few thoughts.