Very good that you got a quieter background noise.
But when generalizing, I have my doubts.
If everything is checked twice (tone arm proper wiring , ground loops) and the arm end/preamplifier input interconnect is of reasonable length (50,70cm) there is not much -if any- to be gained going from single ended to balance.
I had done some tests in the past, please visit and comment here.
Digitizing vinyl
Digitizing vinyl
Digitizing vinyl
Digitizing vinyl
Digitizing vinyl
(I am still using unbalanced connections to my turntable
)George
If wired up correctly, the pickup coils are floating at audio frequencies. Assuming the wires are twisted in the arm to minimize loop area and you are using decent screened cable between the T/T and the preamp, you should have very little noise indeed. for thermal noise, I would always assume that a balanced solution can be bested by a good single ended design.
I see on your plots George that the HF noise is lower on the balanced - so might be there's a benefit there - but is it audible?
However, I won't deny anyone their fun if they believe balanced is better!
I see on your plots George that the HF noise is lower on the balanced - so might be there's a benefit there - but is it audible?
However, I won't deny anyone their fun if they believe balanced is better!
Not with these ears (mine)
but the difference was noticeable in the FFT.That test was done with unscreened, tightly twisted wires. I guess that if wiring was also screened , the upper frequency band would have been much more quieter.
As you say, the arm wiring configuration (twisting and ground poops) is critical for low frequency noise.
George
George,
Interesting images you made between differential and single ended noise with different cable lengths.
Did you also happen to have measured the achieved CMRR to confirm that you had everything optimised for the differential/balanced layout ?
This is because the slightest anomaly will ruin a good CMRR and therefore corrupt your noise measurements to some degree.
Hans
Interesting images you made between differential and single ended noise with different cable lengths.
Did you also happen to have measured the achieved CMRR to confirm that you had everything optimised for the differential/balanced layout ?
This is because the slightest anomaly will ruin a good CMRR and therefore corrupt your noise measurements to some degree.
Hans
That’s correct Hans. I haven’t claimed impeccable implementation, I ‘ve mentioned that in one of the link above.
I haven’t done a CMRR test on that preamplifier but nothing stops me from trying to do one in the following days (easier said than done
)The only measurements I can supply now for that preamplifier are here
Digitizing vinyl
Digitizing vinyl
and here
Implementing a “Y Out” on an Oscilloscope
Implementing a “Y Out” on an Oscilloscope
George
Very good that you got a quieter background noise.
But when generalizing, I have my doubts.
If everything is checked twice (tone arm proper wiring , ground loops) and the arm end/preamplifier input interconnect is of reasonable length (50,70cm) there is not much -if any- to be gained going from single ended to balance.
I had done some tests in the past, please visit and comment here.
Digitizing vinyl
Digitizing vinyl
Digitizing vinyl
Digitizing vinyl
Digitizing vinyl
(I am still using unbalanced connections to my turntable
George
Hi George,
Thank you for posting this. I read the references with much interest and must say that, although differences are there, they are not overwhelming.
In my case, I have a turntable that I never have been able to get reasonably noise free. Especially hum. Yamaha GT-750. Because I want to play my albums again, I decided to try a balanced setup. And this totally solved the problem, to the point that I have never heard less noise coming from a turntable.
Now, I might be able to replicate your measurements in my specific setup by grounding one of the balanced inputs. Will be continued.
Hi vacu
As far as I can tell, the signal wiring of your GT-750 has all four cartridge wires floating and that is good.
Now check if your cartridge has one of the output pins connected with a prong to it’s body shield. There might be located your problem with the formation of a ground loop.
Depending of if you ground the arm ground pin to your preamplifier, the hum becomes louder or more quite but it never goes away.
So, before doing the single ended/balance comparison, please check if one of the minus pins of your cartridge is connected to body shield and report back.
George
As far as I can tell, the signal wiring of your GT-750 has all four cartridge wires floating and that is good.
Now check if your cartridge has one of the output pins connected with a prong to it’s body shield. There might be located your problem with the formation of a ground loop.
Depending of if you ground the arm ground pin to your preamplifier, the hum becomes louder or more quite but it never goes away.
So, before doing the single ended/balance comparison, please check if one of the minus pins of your cartridge is connected to body shield and report back.
George
Attachments
Ah, alright.
I am Godblessing radio for many decades now. Listening to the radio a part of me. (AMbr, SW, FMbr, web radio in chronological order of close encounter)
George
Hi George, your heuristic skills never cease to amaze me. Your possible explanation for the formation of a ground loop definitively makes sense. I am happy to report though that this is not were the problem came from. So the coast is clear to do some measurements.
But not today, the weather is just brilliant, and before we all get locked down, I will be going out for a long bike ride.
Stay safe,
Paul
“ In my case, I have a turntable that I never have been able to get reasonably noise free. Especially hum. Yamaha GT-750. Because I want to play my albums again, I decided to try a balanced setup. And this totally solved the problem, to the point that I have never heard less noise coming from a turntable. ”
I had a terrible noise noise problem on an SME 3009 V2 arm I bought off eBay about a year ago. To get it quiet, I had to bunch the T/T to preamp interconnect, move it around etc etc. only after fiddling for about 10 minutes found I get it noise free.
Turns out the problem in my case was that the ground connections on the L and R channels were swapped. Clearly the arm had been re-wired, become noisy and I suspect that’s why the arm was sold.
Anyway, it’s absolutely noiseless now whereas my Rega arm is good, but not as good as the SME.
I had a terrible noise noise problem on an SME 3009 V2 arm I bought off eBay about a year ago. To get it quiet, I had to bunch the T/T to preamp interconnect, move it around etc etc. only after fiddling for about 10 minutes found I get it noise free.
Turns out the problem in my case was that the ground connections on the L and R channels were swapped. Clearly the arm had been re-wired, become noisy and I suspect that’s why the arm was sold.
Anyway, it’s absolutely noiseless now whereas my Rega arm is good, but not as good as the SME.
Did sadly lose Bill Withers today.
Thanks for the rec, on Ray!
I did have best of Bill Withers playing last night over dinner. Took me back to 1985 when I helped a friend buy his first hifi. The only test track he wanted to listen to was 'The two of us'. I couldn't listen to it again for about 10 years!
@Bob: I was more thinking '**** you we're from texas'
The program is on youtube YouTube hopefully not country locked. Knowing that, even in the 21st century some musicians like to record standing around a single microphone makes me very happy. That to me is music making in a pure and wonderful form. I also love Rich Hall as a presenter which makes the program more enjoyable and very informative to those of us not from the mountains.