A dream came true - R2R.

[Foxbat]

Well, not quite. The initial number at 1KHz was similar, I got 74dB, but I poked in deeper.

I tried different tubes in that position, and observed up to 10dB difference between some samples.

And there was also very strong frequency effect, with CMRR dropping by 26dB going from 1 KHz to 20 KHz.

Of course the circuits are most likely different to some degree, but the general effects might be similar.

 

[Atmasphere]

Well, not quite. The initial number at 1KHz was similar, I got 74dB, but I poked in deeper.

I tried different tubes in that position, and observed up to 10dB difference between some samples.

And there was also very strong frequency effect, with CMRR dropping by 26dB going from 1 KHz to 20 KHz.

Of course the circuits are most likely different to some degree, but the general effects might be similar.

What bit of equipment were you testing?

Apparently though you got much better values than you maintained was possible in your prior posts.

 

[Foxbat]

It was a phono stage, and I was talking about worst case specification, which is in line with my measurements.

But the bottom line is there is most likely no benefit at all to connecting a floating source in balanced way in a typical home environment, but there is definitely a noise penalty - in case of tubes.

Millions of people enjoy their unbalanced phono setup without any issues. In that regard the balanced phono input is like a root canal - great in some cases, but certainly not the first thing your dentist does.

But yes, we are going to agree to disagree.

 

[Atmasphere]

But the bottom line is there is most likely no benefit at all to connecting a floating source in balanced way in a typical home environment, but there is definitely a noise penalty - in case of tubes.

There's no noise penalty at all- that bit is false. The advantage of a floating source is it maximizes the CMRR available at the input of the preamp. You have persisted with this noise claim but so far not provided any evidence or citations to back it up.

The benefit of using a balanced line is, if done properly, the cable ceases to impose an artifact and therefore does not have to be expensive to be completely neutral. By 'artifact', if you've ever auditioned different cables side by side and heard a difference, that's what I'm talking about.

If the cable messes something up, it does not matter how good the electronics and speakers are downstream, they cannot make up for errors at the input. So this is the most important place to get things right.

You can always make improvements or changes with a single-ended cables, but they will never be completely neutral (next year whoever made the cable will have a better version, and if they don't someone else will...). It is this neutrality of balanced lines which is why the better you make your system, the better LPs and tapes from the 50s and 60s sound- they were all made using balanced connections.

 

[Foxbat]

I think we have made enough circles. My noise calculation was provided several posts back, so at this point I am moving on.

 

[Atmasphere]

I'm guess the noise calculation was based on a false premise.