Let us know your findings but please do state what you are comparing your PS with, eg what you had to start with and what changes you noticed with your new PS.
In my case, as posted here, I went nearly by the book, then upgraded PS caps to compare, and then compared again vs a non smps oversized lab supply. There were subtle differences, more a question of staste and variations around the same theme. Not conclusive for me.
But would welcome any real sonic upgrade, so keep us posted
Claude
In my case, as posted here, I went nearly by the book, then upgraded PS caps to compare, and then compared again vs a non smps oversized lab supply. There were subtle differences, more a question of staste and variations around the same theme. Not conclusive for me.
But would welcome any real sonic upgrade, so keep us posted
Claude
I am using a sigma11 with my B1K. I can’t credibly claim it made a major sonic difference vs the SMPS, but it’s a good cure for PSU nervosa (and a really fun project to build — I’ve made two now).
If you haven’t built the sigma11 before, my only recommendation is to buy a bunch of zeners — I literally tested 100 trying to get as close to 24v as I could.
I’m also interested in anyone’s mods to the B1K. Going to have some free time here and will need something to tinker with..
If you haven’t built the sigma11 before, my only recommendation is to buy a bunch of zeners — I literally tested 100 trying to get as close to 24v as I could.
I’m also interested in anyone’s mods to the B1K. Going to have some free time here and will need something to tinker with..
View attachment 826387
So, after three days of pleasant work, my Nutube B1 has born. I don't believe I put it together in the best way, with the best parts or using the best solder, but finally I'm getting the first notes out of its board. My first impression is of a good, deeper sound stage with good detail, it seems that now music almost "comes alive". There is just a little hum, but I can slightly hear it only turning the volume knob to maximum and besides, at its minimum position also a little hiss is audible, but only placing my hear close to the tweeter. I almost solved the ringing issue (which clearly affects my sample of Nutube) following Jim 6l6 advise and placing, but not glueing, two pencil erasers on the Nutube, one upon the other. Weak ringing still appears only if I rub the upper cover of the chassis, but I believe that if I'll make it deaf to vibrations, things would go better. By the way, it's a spare chassis, which I recovered from another building, I'm planning to buy a new one, smaller, from Hifi2000. I'm waiting also for a regulated PS from China. Now I'm using a 24v SMPS, bought from Digikey, I will see if there'll be a sound improvement. My B1 Nutube drives a diy amp made by Hypex ucd700/SMPS1200 modules and SVS Prime Pinnacle loudspeakers. I'm, for now, well enough satisfied with the results and I have to say that, with regard to the other preamp I was using, the B1 Nutube represents a great improvement for my audio chain.
Thank you Mr Pass and best wishes!
Gaetano. View attachment 826366 View attachment 826375 View attachment 826387
Thank you Mr Pass and best wishes!
Gaetano. View attachment 826366 View attachment 826375 View attachment 826387
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Bravo Gaetan Congratulations !
Enjoy this super cool Papa design jfet's with triodes preamplifier.
Kind regardsAttachments
I know this preamp is phase inverting, so I've already connected my loudspeaker in reverse polarity. But actually I think I've not well understood facts about the T7/T8 voltage. Do you think 9.7V is the value which obtains the best sound? I read that varying the voltage on the 10k trim pots can vary the relative content of 2nd and 3rd harmonic distorsion. How can I maximize one over the other? And how does this affect sound?
Thank you, Gaetano.
I prefer my system at 9.7V. Others like 9.5, some like 14V or anything in between. To quote Mr. Pass:
"Voltage at 12 VDC is approximately the 2nd harmonic null point where we get about .3 % distortion in 3rd harmonics. As we go lower we start getting positive phase 2nd harmonic, and it will hit 1.5% at 1 volt AC output with about 9.5 VDC on the T7 or T8 test points. Voltages higher will give negative phase second harmonic."
and:
"Negative phase 2nd harmonic distortion is distinguished from positive phase by a difference perception of sound quality. It appears that listeners find a greater sense of space and depth with negative phase, and an illusion of being able to better localize location of sources in the audio. By contrast, positive phase brings a greater sense of presence. When the second harmonic is nulled, the result is sometimes described as having more dynamic quality."
"Voltage at 12 VDC is approximately the 2nd harmonic null point where we get about .3 % distortion in 3rd harmonics. As we go lower we start getting positive phase 2nd harmonic, and it will hit 1.5% at 1 volt AC output with about 9.5 VDC on the T7 or T8 test points. Voltages higher will give negative phase second harmonic."
and:
"Negative phase 2nd harmonic distortion is distinguished from positive phase by a difference perception of sound quality. It appears that listeners find a greater sense of space and depth with negative phase, and an illusion of being able to better localize location of sources in the audio. By contrast, positive phase brings a greater sense of presence. When the second harmonic is nulled, the result is sometimes described as having more dynamic quality."
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Nice ! Congrats
Mmm but a question ...
Normally the value and even type of tube bias cap ...have a lot of difference in sound ..I don't think I ever see them above 1000uf .does it make any diff in Korg nu tube?
Hi Anthony, didn't dare to touch it for that reason, but upgraded the PS caps.
Hi Gaetano, you may want to use the search function and see what I posted re sound and voltage. I do'nt know if you are running at over 12V, but of so then it is very likely that inverting the LS cables indeed helped getting back the correct phase BUT at that voltage while inverting cables you are likely to run in 'normal' positive H2, hence not using the B1 Korg like most of us with negative H2. You could prefer it that way though... if not, run below 12V.
Note that at the cost of the absolute phase impact, something you may or may not be sensitive to, you could easily figure out if you prefer negative or positive H2 by simply keeping your 14V or so setting... and inverting (getting back to normal) your LS cables.
More confused? Normal... LOL!
Claude
Hi Gaetano, you may want to use the search function and see what I posted re sound and voltage. I do'nt know if you are running at over 12V, but of so then it is very likely that inverting the LS cables indeed helped getting back the correct phase BUT at that voltage while inverting cables you are likely to run in 'normal' positive H2, hence not using the B1 Korg like most of us with negative H2. You could prefer it that way though... if not, run below 12V.
Note that at the cost of the absolute phase impact, something you may or may not be sensitive to, you could easily figure out if you prefer negative or positive H2 by simply keeping your 14V or so setting... and inverting (getting back to normal) your LS cables.
More confused? Normal... LOL!
Claude
WITHOUT inverting the LS cables, so at the cost of absolute polarity (as the B1 Korg is inherently phase inverting):
- between 9V and 12V or so, positive (classic) H2, the lower the voltage, the more of it
- between 12V (or so) and 15V, negative H2, the higher the voltage, the more of it.
- Around 12V likely to be your H2 null point.
Now, inverting the LS cables, as suggested by Papa, brings back the absolute polarity. Doing so, it also inverts the H2 sign, so we now have:
- between 9V and 12V or so, negative H2, the lower the voltage, the more of it
- between 12V (or so) and 15V, positive H2, the higher the voltage, the more of it.
- Around 12V likely to be your H2 null point.
That gives you all combinations, hopefully it helps you and future builders
Claude
- between 9V and 12V or so, positive (classic) H2, the lower the voltage, the more of it
- between 12V (or so) and 15V, negative H2, the higher the voltage, the more of it.
- Around 12V likely to be your H2 null point.
Now, inverting the LS cables, as suggested by Papa, brings back the absolute polarity. Doing so, it also inverts the H2 sign, so we now have:
- between 9V and 12V or so, negative H2, the lower the voltage, the more of it
- between 12V (or so) and 15V, positive H2, the higher the voltage, the more of it.
- Around 12V likely to be your H2 null point.
That gives you all combinations, hopefully it helps you and future builders
Claude
Because "It appears that listeners find a greater sense of space and depth with negative phase, and an illusion of being able to better localize location of sources in the audio. . ." and prefer that to the "greater sense of presence" that positive provides.
To me, it makes some type of weird sense that the distortion should trail the fundamental (negative), not lead it (positive).
For more, see page 2 of attached original B1K article.
To me, it makes some type of weird sense that the distortion should trail the fundamental (negative), not lead it (positive).
For more, see page 2 of attached original B1K article.
It’s unknown. The preference was originally found with a different amplifier with an adjustable knob that was unmarked, but encouraged to be set to various positions for ‘best sound’. The preferred setting, set blindly, was for a negative phase H2. If you look at Nelson’s presentation from BAF 2018 he talks about it around the 22:00 mark of the video.
You have to watch the videos in this page -
Linear Systems
You have to watch the videos in this page -
Linear Systems