B1 with Korg Triode

[aljordan]

I just built a kit for a friend and the T5 and T6 voltages are exactly the same as yours, so hopefully it is within range.

HI All,

Have just completed my build of the B1 Nutube, and has measured in T7 and T8. No Smoke yet 🙂 However, T5 and T6 measure 0,67V, i.e. plate voltage is a little up. Is this a issue ? I assumed it to be within the acceptable range, but it would be good to get a little input.

Mikael

 

[rikiheck]

Hi, there is also a specific thread about a balanced version of the B1 Nutube. I don't remember his name, but this member did a lot of deep tests and measurements on this particular configuration.

That thread is here: Balanced B1 with Korg Triode.

Other than this, I used output transformers to get balanced signal from se with good results to my ears.

I know that this is possible but do not know how to do it myself! What transformers did you use? How exactly did you connect them? I've read this document, and it gives a couple different options. I'm guessing that maybe this is the simple option 2.2?

 

[rikiheck]

I also just found this article by Gary Galo.

 

[flargosa]

Do you reverse polarity of one speaker or both speakers? My understanding is to reverse one, but not sure.

 

[6L6]

Both speakers.

Try it both ways. ("normal" and "reversed") Depending on what the rest of your system does it will likely sound better on way rather than the other, and it's completely inconsequential which way it is. 🙂

 

[6L6]

What transformers did you use? How exactly did you connect them?

...

I'm guessing that maybe this is the simple option 2.2?

Yes.

Try the CineMag CM-10100

 

[Leeuwarden]

What are the pro’s and cons of using a transformer to get balanced output?

 

[6L6]

Pros - You get balanced output.

Cons - none, really. Good transformers are not inexpensive, so maybe cost.

 

[Leeuwarden]

Thanks! Given the cost to build a B1K ik think I have some money left for transformers... I hope 🙂

 

[irishpatrick33]

I created a sound maze that functions similar to the Nutube kit that encases the tube. My microphonics aren’t bad anymore, but I felt like pursuing perfection.

It has minimal affect on microphonics. I can make a clap a little closer now without ringing. I am a bit surprised. It seems the tube may be getting most of vibration through board (yet rubber mounts didn’t help)? I might try prying the tube away from adhesive foam to see if a little more float knocks down vibration transmission.

 

[avdesignguru]

The transmission loss of your case cover appears to be poor. Try damping material applied directly to the glass top of the NuTube. Search this thread for 6L6's recommendations.

 

[irishpatrick33]

The top of the Nutube enclosure is sealed with glass. There are tiny inlets on the enclosure that snake around (sound maze) and provide a vent for Nutube heat. I might print a totally sealed enclosure and then test. I’ve put material on Nutube, doesn’t make a difference.

 

[avdesignguru]

Different NuTubes appear to vary in how much a particular filament resonates in response to external stimulus. My guess is manufacturing tolerance on the filament tensioning. Of the six Nutubes I've installed in various different circuit designs, I've only had one that had self-generated ringing and a second that would only ring if the tube glass was tapped on directly. I moved the fussy tube to my NuClass D amp, which offers adjustable negative feedback. Bringing the NFB level up a bit got rid of the ringing.

In my spare time (of which I now have plenty) I may try lowering the filament voltage just a bit on that bad tube to see if it affects filament tension and possibly the microphonic level of the device.

 

[flargosa]

If left on 24/7 how many months before sound degradation is noticeable? Would have been great if NuTubes had a socket for easier replacement like regular tubes.

 

[cccochran]

Korg B1 Problems

Hi everybody: novice kit builder needs troubleshooting help.
Stock kit fired up perfectly. Nutube blue even on both sides. T1 thru T6 all within spec. T7 + T8 set to 9.5v.

No volume output. If I turn ALL the way to max, I get just a bit of sound, tho very little.
Where do I start to track down my errors(s)?
Thanks for your help.
Craig

 

[Zen Mod]

measure ohms between RCA hot and GND , must be same as vol pot resistance, fixed value even if you rotate pot


measure ohms between hot and gnd on pcb in, it must vary from 0 to max vol pot resistance, while varying pot

same behavior for both channels

 

[cccochran]

Thanks Zen Mod: I hope I'm following you correctly...
PCB in left channel 1.7 ohms full counter clockwise; 48.7k ohms full clockwise
PCB right channel 0.6 ohms full counter clockwise; 49.4k ohms full clockwise.

RCA ground/hot:
input 2 white 48.9k ohms; red 49.4k ohms (fixed)
input 1 no reading white or red.

Need to reflow solder at barrel and tab input 1?

Thank you
Craig

 

[Tuberoller]

About half way through on the complete store kit and I’m getting 9 volts instead of 24. Not sure why. Am I missing something obvious?

 

[ro9397]

What is ETA for the full kit in stock again?

 

[JohnnoG]

The Nutube is claimed to be a 30 000 Hour Functioning Device.
That would be 1250 Days at 24 Hours Switch on, Close to Four Years.

It would be of interest to know any estimated hours of usage on the Nutubes in use at present ?
I am wondering if there is a Period of use where the Nutube is perceived to be delivering at a Optimum SQ, I am not sure how long this period would be expected to last.

Also there are some individuals who are familiar with having a selection of NuTube's used by themselves, has any been noticeably different in their SQ other than the known of Harmonic Anomaly ?