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.

 

[Erik-Alexander]

Get ready to be surprised. I just finished the project of building a super-low-cost head pream. All tube, and the price point around $250 in parts.

Today I powered it up for the first time in its final configuration and I am seriously shocked by its sound. To me it started as just an educational and a Youtube fun project, but based on what I heard I would not be surprised if this setup became one of my popular choices. And as you know I have a few very fine machines to choose from.

Don't diminish your A810, it has a very capable mechanism, and with good external electronics it becomes a real world class player.

Any new developments on your tape head pre-amp? I’m looking into it as well.

 

[Foxbat]

Well, that one was finished some time ago, you can see the final videos of it. The project goals were achieved, and the device successfully put on the shelf.

 

[Erik-Alexander]

Well, that one was finished some time ago, you can see the final videos of it. The project goals were achieved, and the device successfully put on the shelf.

I have a Metaxas with direct head output in XLR. Could that work with your pre amp?

 

[Foxbat]

Well, it is not really "my" preamp, it is the Marantz one. But be it as it may, it all depends on the playback head they have, if it is medium to high inductance, then most likely it will work fine together.

 

[jazzfun]

Well, it is not really "my" preamp, it is the Marantz one. But be it as it may, it all depends on the playback head they have, if it is medium to high inductance, then most likely it will work fine together.

Does it work with Telefunken M15 and Mara JH-10?

 

[adrianywu]

You guys can read up my experience with the preamp here: https://www.psaudio.com/blogs/copper/my-experience-with-commercial-four-track-tapes-part-two
It is a really remarkable performer, even if the low cost is not taken into account. I dare say it is better than the internal repro electronics in 90% of tape machines.

 

[Foxbat]

Does it work with Telefunken M15 and Mara JH-10?

I don't have the direct output on my M15A, and on JH-110 I have the FM head, that one will work, but off the top of my head I don't know the original heads inductance. Just remember, that the 47K input resistor might have to be replaced for higher inductance head, so I put a 100K trimpot there instead.

 

[jazzfun]

I don't have the direct output on my M15A, and on JH-110 I have the FM head, that one will work, but off the top of my head I don't know the original heads inductance. Just remember, that the 47K input resistor might have to be replaced for higher inductance head, so I put a 100K trimpot there instead.

I remember I ordered the FM head in my JH-110.Thank you!Victor!

 

[Foxbat]

How do you like your JH-110? Any issues?

 

[jazzfun]

How do you like your JH-110? Any issues?

Actually, I haven't installed "your" preamp yet. I plan to order an extra FM head for the JH-110 to connect to the preamp. I hope to be able to connect both the Telefunken M15 and the JH-110 to the preamp. I'm still learning. . . . .

 

[Foxbat]

If I find time, I might connect that preamp to my JH-110... as soon as I move some pieces around, right now the room is kinda busy. You can see the JH-110 in the second row.

 

[Atmasphere]

If I find time, I might connect that preamp to my JH-110... as soon as I move some pieces around, right now the room is kinda busy. You can see the JH-110 in the second row.


View attachment 141756

Awesome!
I don't see any keyboards!

 

[Foxbat]

My wife's piano is upstairs.

 

[Atmasphere]

A nice set of Neumanns and you can make it sound like its downstairs too.