I just typed the same thought, before I read yours, dazz. An electric celesta would be the perfect use for them, with little tiny rubber mallets, worked from a keyboard.
I agree with the electronic celesta idea. Noritake would have their work cut out manufacturing different sized tubes with perfectly pitched rings. It would be nice to have a way of fine tuning them. I wonder which element determines the ring - the grid? Glass? Oh to have a factory.
I know this is an old video and you may not see this… But I have a Nutube Ibanez tube screamer. When I run it at 18v it seems to be miceophonic when I touch the switch only. If I can touch other parts it remains quiet. At 9v there is no noise when the switch is tapped. Is it a bad Nutube?
Looks like there are 2 NuTubes per device and are intended for stereo applications. This may be why they're marketing it toward that end. The Black and Red Banana at the top left are generally for DC supply inputs. I think I saw 5V - 30V in the PCB silkscreen. This may be for ultra quiet DC Power from a bench supply instead of a sloppy 12V wall wart. The IC between the caps, I would imagine is a a Low Dropout Regulator to generate the board's supply voltage. The IC in the lower right I believe is a stereo amplifier for driving the headphone jack. Without a schematic, it is tough to say if the volume is controlling the gain on the headphone amp or the pre-amp gain of the NuTube circuit...
"Ding...ding" There's no question that the Nu-tube is in the signal path. Isolating these things in a power amp with a speaker in the cabinet might be a challenge. I could see these creating an acoustic feedback loop. Very cool video, Brad.
NOTES: in case I didn't make it clear enough, the trimmers on each channel seem to be for the bias voltages, and those large banana plugs are not outputs, but alternate power input terminals. My bad on that. Here's the PDF manual for the Evaluation board with schematic, which I didn't know they had on their site until after the video was published: www.nutube.us/downloads/Nutube%20EvaluationBoard%20manual%20E.pdf
Sounds more like, without an input signal, a feedback loop rather than microphonics. The 'ding' stayed at the same frequency, no matter how or where you were tapping.
Interesting. So, orchestras now have the option of replacing the triangle with a NuTube based electronic device... If they could tune them to make a ping at a given frequency, when you tap them, they could make a really nice electric glockenspiel, or celesta. I think that might be the way to go.
One other point on the hiss (the noise). That hiss is a very well-known problem with the powered 3.5mm input jacks on video cameras. They are not normal 3.5mm jacks and you can't plug output from any 3.5mm device into them. Their designed for special microphones like the ones from Rode that know what to do with the power. The hiss has to do with the auto-gain in the camera and also might have to do with the way the Teac output controls are maxed out. You can dial up or down the overall input level on your JVC camera, but the auto-gain is always working to even out your audio levels so that two people talking at different levels get "evened-out" to an average audio level. The result, if the output has its own amplification (which it does in this experiment) is always hiss. A special device from Beachtek that goes between the headphone output and your camera and that defeats auto-gain will solve that problem if you're using the Korg board's headphone output jack. You might get different results when using line-out into the 3.5mm jack. The RCA output on the main board is probably line out. I am willing to bet when you hardwire this into something (I can't wait to see), that problem will go away.
here's a link to one of those devices that adapts audio for input into a camcorder's 3.5mm jack. This one has XLR, 1/4", and 3.5mm (mini jack) inputs. a.co/dS2rOIe
Top right IC is obvously a regulator and bottom right a headphone amp circuit. Theres some mosfets activated by the optuput of the nutubes to pass things on as well.
not sure if you know this:(Caution of previous batch) The silk print on board says "12V centre +" but adding 12V will break 3.3 V regulator (NJM2884), which maximum input is 10V. Please never add more than 10 V as a power supply. I strongly recommend to use 006P (9V) battery for power supply.I came across this information while researching the evaluation board.
i think these are easy to burn up, this could be why they sent you so many of them. I requested the data sheet after your first video and they sent it within 24 hrs. It was very nice of them to send you the boards too. I might have to look into this for a build. thanks for sharing!
it appears they are already selling amps using these on amazon. the VOX MV50CR Series Amplifier Head is what i searched for, also seen a couple YT videos demoing them. who knew lol
The Vox MV50 is a little 50 watt tube head that has NuTube technology. I'd be interested to see inside one and see if they have the tube encased in anything.
After watching a couple demos, it doesn't look like it's enclosed, other than the amp enclosure. There's a clear window on the top to view the tube glow.
It is not encased in anything. No noise evident when the mounted tube casing is tapped, but I do get some microphonics when the treble tone control is tapped
I think the NuTube needs cushioning to avoid vibration microphonics. You know, like , that double-sided tape that's made of foam? If you put that on the backside of the NuTube before soldering it to the board, that might help reduce the effects of vibration. Vox is using them on their new MV series of amps, and also Ibanez used it on a new Tube Screamer pedal, so there's definitely something they're doing to keep vibration from causing issues. Maybe send another email to your friend at Korg asking for documentation on the evaluation board, as well as instructions on mounting the tube mechanically to a chassis and suchlike things? Even if it's more of a show piece than an useful piece of tech, it's cool that someone is thinking about the future of tubes.
But if you put these as a preamp in a 120W head, then play stage volume, I bet you'll be in big trouble, regardless of the cushioning ;) I've had significantly less microphonic preamp tubes go haywire from feedback But OK for a headphone amp, perhaps
I imagine it would be a feasible way to reduce vibrations by, like you said, solder it to a board with the foam tape cushion between tube/VFD and the board it's soldered, then solder that board to the main one with thin flexible wires instead of pins, and that board also foam cushioned. I can imagine a good enough adhesive will hold it all in place until something a lot more worrying happens to the unit, or if in doubt, some last case form of contention like screw posts that don't normally touch the board. That would work against vibrations directly to the board it's attached to, but for sound induced ones there would need to be something else, don't think it would be horrible to think of something too (sound proofing ain't impossible after all)
The only noise I heard was the tape hiss. I'm here in my studio with Genelecs. Can't wait to see you building a guitar amp with it. It's interesting how the microphony goes away once there is signal. I'm guessing the signal moves the grid and forces it to oscillate with whatever signal is in instead of the external vibrations. Is that possible?
No it´s rather that inbuilt camera AGC...hear the upcomming and raising noisefloor when the input signal vanished....typical AGC behavior. I bet the ProtoBoard is real quiet when hooked up to a nice spectrum analyzer instead of a poor camera audio input....
Yes. Tape hiss. Haven't heard that in awhile. How about a digital signal next time? Lots of compression. Numbers 2 - 10 on the volume dial are pretty similar. You sure it's not the camera inputs Brad? Would be interested in seeing a scope trace too while you're monkeying with it.
It´s probably from the manufacturing... I have a VFD that I intend to use as a tube and if I tap it and hold it close to my ear I can hear it resonating
There's no doubt that for guitar, we want to hear how these things behave when overdriven/underdriven/starved... all the ways around the block you might use with a 12ax7. Let's see what kind of a sonic fingerprint they have.
Plinking one's finger on a vacuum tube while operating can do the same thing. Some folks even argue that it's all part of the tube mojo. Tube sockets that use rubber mounting grommets to deal with vibration are often employed when it becomes a problem or for reliability. Anyway, seeing it happen here is actually a very cool thing if you think about it - it let's one know that a nutube seems to behave very much like the tubes we all know. Thanks for vid - very interesting.
With an amplification factor 25% lower than a 12AU7, you’ll probably need all four to make anything useful. Unless, you pair it with a solid state opamp, which is probably what Vox, Korg, and Ibanez have done. Good luck!
The Guitologist how about using one of the jfet-as-triode circuits from Runoffgroove or BuildYourOwnClone. The voltages would be similar to what the nutube needs, the circuits themselves are identical to tube circuits (with a few resistor changes) and they have a ton of gain, and sound awesome.
The microphonics is due to the design of VFDs, which uses a long cathode filament only supported at its ends and it vibrates like a string. If you tap a VFD, it will make a ding.
You could build a amp using all of those just by making it step up the voltage slightly to each one where you would have a selector switch like A,B,C,D where each selection just ups the voltage slightly so that each a,b,c,d would give different gains ????
Those monster rca cabel serie i think is directional.they should have an arrow marking from source to amplifer on them and is best is used in one direction.
I have been following these tubes for a while. They have been around for a whilem The unfortunate thing is that they are simply WAY to expensive, plus they don't have much gain at all. For that reason i designed a boost converter instead from a 12V supply (which you can use for the filaments). Btw these nutubes have been used in Vox amps.
You don´t need gain from the tube (if you need gain get it elswhere), you need the distortion footprint from a tube by today that´s what it is all about.... The NuTube is designed to be easliy interfaced with semicons (OpAmps, transistors or FETs) not to be the only active thing in your design. and also that´s why they are build like a Dual inline package, for PCB mount... If you want an all tube amp, go for the obvious, but not for the NuTube.
TubiCal . That's totally true. So you need to have some kind of opamp gain stage in front of it. Which sometimes makes it difficult to fit with certain pedals etc. I am just saying this from a consumer point of view. Also it's a little more difficult to 'fine tune' your distortion footprint. (A lot of times you would combine different ones)
Very cool video Brad. I tried to see if someone mentioned this in another comment.. but the reason for the daughter-board (versus soldering the NuTube right on to the mainboard) is probably because Korg envisions modules of other types (maybe entirely different purposes) working with that main board (or already has). So, this design gives them the flexibility to design the main board without having to concern itself with the exact design of the chip that will be mounted to it. That is a common design technique in the digital industry. Also, regarding the microphonics, etc... this kit is probably what's called a "reference design." It's provided so many manufacturers that are thinking of using the NuTube can get going quickly and experiment with a wide range applications. When we do that in the digital industry, it's not mean to be perfect. It's meant to help with proof of concept. Sort of like a turnkey professional version of a breadboard set up that you might come up with in your lab. A manufacturer would very likely not include that entire package in their final product. For example, you can see how Vox made a daughter board of their own in one of the images here: www.voxamps.com/MVX150H. This daughterboard based design also makes it easy to replace NuTube in "the field."
I have 5 nutubes and I'm working on a low power amplifier board using all nutubes in the signal path. The complete pain in the arse with these things is that they are hot cathode, so you have to rethink all the usual circuits. Things like cathode followers and long tailed pairs also have both the heater current and cathode current running through the same path. So you need to re-work the usual equations. I have completely failed to work out how to do a cascode current source, since the cathode isn't floating.
this is new from Vox. a 150W head and a 150 watt combo using nutube MVX150C1 VOX’s next-generation amplifiers equipped with Nutube, 150 watts of power, and a UK-made Celestion Redback speaker 150W amp equipped with a Nutube vacuum tube in both the pre-amp and power amp sections Two-channel design covers a wide range of tones, from pure clean sounds to modern hi-gain Combo amp features a UK-made Celestion Redback speaker
I didn't hear any noise using the vox mv50. anyway I'm really confused about the microphonic noises with vibrations because it doesn't happen with vox amps. maybe they blocked the nutube so well to isolate vibrations?....
What about building the front end of a guitar amp up to the volume control and maybe a PL81 Line Timebase tubes as the output, the two small variable resistors are bias setting, it's a vacuum tube my friend but not as we know it.
I have one of the Vox MV50 AC amps. I've used it sitting on the tiny Vox 1x8 cab they make for it and also on a bigger H&K 1x12 cab and I noticed no microphonics or other noise. Works well for me. Sounds decent. Pretty loud, considering it fits in my hand, but that's probably due to the D-class output stage. Wish it had an effects loop. I've ordered one of those Ibanez Nutube based Tube Screamers but haven't got it yet. Based on my experience with the MV50 I'd expect it to work OK.
Brad, this is a brand new thing and it's gonna have issues. I say, props to Korg for allocating a team and an ostensibly healthy budget to come up with something really next gen. I don't know what the specs are but it appears to be quite a departure from current tube tech and it should be really exciting to explore. It was cool of those forward-thinking Korg-folk to Fedex you a little nugget of future tech. Mess with it. Ponder it. Come up with something we've never seen. There must be a fix/workaround/use for those strangely musical microphonics.
Having looked around for this tech in the present-day (lol), it doesn't seem to have gotten much traction. Maybe there are so many digital options that a new (weird-looking) tube seemed redundant. I hope somebody comes up with a novel way to take advantage of these little glowy sticks of funky Japanese tech. The Nutube amp that Toshi Hiketa plays at the 2015 NAMM on their Gallery page sounds great. And it's tiny... But then so is a laptop. [sad face]
I've had a Vox MV50 AC for a couple of months now. I've played it pretty hard, usually on top of a cabinet with the "deep" switch engaged. I haven't noticed any microphonics or undue hiss (like when using a string of pedals). I'm not going to open it, though. It ain't broke so I'm not going to fix it.
I'm with you on the mircophony, sounds like a major problem. It's at a pretty high frequency though, so maybe a sharp LPF would be an option to deal with it (for a guitar distortion, would be horrible for HiFi of course)? A few critical remarks: Firstly, this is a evaluation board, I'm quite sure it's not meant to be super HiFi/low noise/etc. . If you actually want to test noise levels, why not hook the output up to a scope while nothing is fed into the input (or with a tone generator on the input). In the current setup, noise might be coming from any of the sources, why blame the tube? The IC is probably an op-amp (acting as a buffer), which might also be noisy. I'm not convinced by these things either. Have you tried curve tracing one? Would be interesting to see some realistic test results, data sheets are usually overly optimistic for modern tubes. Properly testing the tube will also give you a much better idea of what component values should be ideal for your tubes. In conclusion: would be super interesting to see some test on these things!
I think the purpose of Nutube is to be a viable alternative to vacuum tubes which we all know are highly inefficient. I am very happy to see in this video that Nutube works very well considering the audio source is from an old cassette player. Yes it is microphonic but even the microphonic sounds really pleasing and I believe Korg can still resolve this "issue". Overall, I can see Nutube dominating not only the amp business in the future but also the hi-fi arena whilst being environmentally friendly :) Cheers from New Zealand!
It is definitely an advantage over the other tubes that it can be operated at semiconductor like voltages and currents. Also the very small heating power for the cathode is impressive. I think, the problem with the microphonics can be solved by an internal design improvement which provides more mechanical damping to the structures and less weight and more spring constant to the control gate suspention to shift the frequency above the audible frequency range. It would be interesting to use the double triode as a differential preamplifier stage to arrange a negative feedback loop in order to improve linearity.
Hey man.. you plugged the headphone out into a camera that is more than likely mic or line level in. Of course it added noise, you added an extra gain stage. And no offense but it went microphonic on the right side only? The side you messed with the bias pot coincidently. I’m just pointing this out because i think these are fascinating and want you to make more videos on these.
Use chip sockets to attach them instead of soldering them directly into your circuits, and you won't have to worry so much about running out of them. That looks like a normal 0.1 inch pin spacing, in which case a socket for a 6502 or 8088 would have plenty of pins to work with, using just one side. The tap test sounds like the closing bell for the stock exchange, or the beginning of _YYZ._
It would be cool to mix this with tubes, the nutube actting like a 12au7/12ax7/12at7 as a preamp driving the signal to the power tubes. I don't know if the nutubes would push enough signal to the power tubes.
With the microphonics it's displaying I can see why its being directed towards headphone amps. Anything more than that and it's going to need to be heavily damped. That being said it does sound pretty good.
1. The small chip on the bottom near the volume control is just an OpAmp. 2. The 3 prong chip that looks like a huge transistor is a simple voltage regulator. 3. Your camera automatically adjusts the volume according to the level of the ambient noise. Turn off auto sound level on your camera and that should do the trick :)
the recommended way to mount the device completely ignored so basically you're banging the elvelope to pcb. it's suppose to be soldered at the tips of the leads and put some thick sponge underneath, like all VFD's are usually mounted and it wouldn't ring. that's why what little circuit board is provided. this is like holding a normal tube in the mid air, banging it with a hammer and saying that it has bad microphonics.
Brad, as long as the nutube does not get hot, you can isolate it easily enough. Do some flying leads between the boards and tape to a piece of foam (that is as long as it does not get too hot and make the foam burn or conductive). I am thinking like the foam that pickups are mounted in, something like that. That will likely fix all the microphonics. A dab of silicone might hold it to the foam and also hold the foam to where you are mounting it. Hope that helps.
Interesting, thanks. I wonder how Ibanez damped vibrations for their Nu Tubescreamer? Hard not to create vibrations in a stomp box when you stomp on it. It'd be cool to see a tear-down of the Nu Tubescreamer.
Have you built any overdrive guitar pedals using these Korg NU tubes or made a small amplifiers using these Korg NU tubes? because I want to see a video of you fixing all the microphone issues and white noise hissing issues to know how these things work. Since you got 4 NU tubes you can build circuits now.
And make another amp using the phosphor display off of an old VCR or microwave oven for giggles. It's likely this thing would be more comparable to those than traditional vacuum tubes.
They've got some combo amps out voxamps.com/VX50Series Mmm, imagine some bass going through a combo and the interesting microphonics you could get. Also voxamps.com/MVX150
Hey Brad... any updates on the NuTube? Did you figure out a project to try? How about some type of foot pedal or a preamp? Maybe an onboard distortion in the cavity of a guitar? Hopefully you figured out how to reduce the microphonics? Keep the vids coming... love 'em!
I couldn't hear any microphonics once there was any signal going though. So, I'd want to see what it's like without any compression. The only background noise I could hear was a hum. Not sure where that's coming from - that might be the power supply.
You've probably seen amps where the socket for the first preamp tube is mounted on rubber grommets to reduce microphonics. Maybe there's a similar way to shock mount the NuTube to achieve the same effect?
Did you ever get the ringing to stop? Sorry so late. I have some Dynamat. I could send you a small piece. Installation and retest would take less time than connecting to you recording rig. Just a thought. Lmk... ;)
Just bought the Vox MV50 ac amp that has these tubes in it. Sounds great. Seems like pretty solid piece of kit. Looking forward to what you do with the NuTubes.
If every tube dings at a different frequency you can always build a glockenspiel
It did seem to have a nice chime to it.
I thought guitar players want that glassy tone.
I just typed the same thought, before I read yours, dazz.
An electric celesta would be the perfect use for them, with little tiny rubber mallets, worked from a keyboard.
I agree with the electronic celesta idea. Noritake would have their work cut out manufacturing different sized tubes with perfectly pitched rings. It would be nice to have a way of fine tuning them. I wonder which element determines the ring - the grid? Glass? Oh to have a factory.
A "Tone Generator" for an analog synth, or an Organ maybe?
show some gratitude , this is the latest tech on earth !
Can't believe this video is 5 years old... congrats on all your success man, I been a sub a long time man...
I know this is an old video and you may not see this…
But
I have a Nutube Ibanez tube screamer.
When I run it at 18v it seems to be miceophonic when I touch the switch only. If I can touch other parts it remains quiet.
At 9v there is no noise when the switch is tapped.
Is it a bad Nutube?
Looks like there are 2 NuTubes per device and are intended for stereo applications. This may be why they're marketing it toward that end. The Black and Red Banana at the top left are generally for DC supply inputs. I think I saw 5V - 30V in the PCB silkscreen. This may be for ultra quiet DC Power from a bench supply instead of a sloppy 12V wall wart. The IC between the caps, I would imagine is a a Low Dropout Regulator to generate the board's supply voltage. The IC in the lower right I believe is a stereo amplifier for driving the headphone jack. Without a schematic, it is tough to say if the volume is controlling the gain on the headphone amp or the pre-amp gain of the NuTube circuit...
You're correct about the power... I was having flashbacks of banana plugs as speaker jacks.
"Ding...ding" There's no question that the Nu-tube is in the signal path. Isolating these things in a power amp with a speaker in the cabinet might be a challenge. I could see these creating an acoustic feedback loop. Very cool video, Brad.
NOTES: in case I didn't make it clear enough, the trimmers on each channel seem to be for the bias voltages, and those large banana plugs are not outputs, but alternate power input terminals. My bad on that. Here's the PDF manual for the Evaluation board with schematic, which I didn't know they had on their site until after the video was published: www.nutube.us/downloads/Nutube%20EvaluationBoard%20manual%20E.pdf
Personally I'm most interested in an amplifier, but I can't wait to see what you do with these.
The red and black terminals are for DC power. The trimmers are for the bias to balance the two halves of the tube.
Sounds more like, without an input signal, a feedback loop rather than microphonics. The 'ding' stayed at the same frequency, no matter how or where you were tapping.
I agree.
Interesting. So, orchestras now have the option of replacing the triangle with a NuTube based electronic device...
If they could tune them to make a ping at a given frequency, when you tap them, they could make a really nice electric glockenspiel, or celesta. I think that might be the way to go.
that tape sounds hella good. i love that you are keen to trying new stuff out
your finger taping is the call for a toast button. useful feature.
Thanks for the show & tell session. It's nice to get a glimpse of this technology at work. Thumbs up!
YEP BEEN WAITING;-)
One other point on the hiss (the noise). That hiss is a very well-known problem with the powered 3.5mm input jacks on video cameras. They are not normal 3.5mm jacks and you can't plug output from any 3.5mm device into them. Their designed for special microphones like the ones from Rode that know what to do with the power. The hiss has to do with the auto-gain in the camera and also might have to do with the way the Teac output controls are maxed out. You can dial up or down the overall input level on your JVC camera, but the auto-gain is always working to even out your audio levels so that two people talking at different levels get "evened-out" to an average audio level. The result, if the output has its own amplification (which it does in this experiment) is always hiss. A special device from Beachtek that goes between the headphone output and your camera and that defeats auto-gain will solve that problem if you're using the Korg board's headphone output jack. You might get different results when using line-out into the 3.5mm jack. The RCA output on the main board is probably line out. I am willing to bet when you hardwire this into something (I can't wait to see), that problem will go away.
here's a link to one of those devices that adapts audio for input into a camcorder's 3.5mm jack. This one has XLR, 1/4", and 3.5mm (mini jack) inputs. a.co/dS2rOIe
The Hector Salamanca of valve signal processing.
Ha!
Ding! Racist much??
Top right IC is obvously a regulator and bottom right a headphone amp circuit. Theres some mosfets activated by the optuput of the nutubes to pass things on as well.
not sure if you know this:(Caution of previous batch) The silk print on board says "12V centre +" but adding 12V will break 3.3 V regulator (NJM2884), which maximum input is 10V. Please never add more than 10 V as a power supply. I strongly recommend to use 006P (9V) battery for power supply.I came across this information while researching the evaluation board.
i think these are easy to burn up, this could be why they sent you so many of them. I requested the data sheet after your first video and they sent it within 24 hrs. It was very nice of them to send you the boards too. I might have to look into this for a build. thanks for sharing!
it appears they are already selling amps using these on amazon. the VOX MV50CR Series Amplifier Head is what i searched for, also seen a couple YT videos demoing them. who knew lol
Could those trim pots be bias pots for each side of the Nutube?
The Vox MV50 is a little 50 watt tube head that has NuTube technology. I'd be interested to see inside one and see if they have the tube encased in anything.
After watching a couple demos, it doesn't look like it's enclosed, other than the amp enclosure. There's a clear window on the top to view the tube glow.
Reckon it has some padding on the bottom
I haven't found any reviews where it's opened up. I imagine you're right.
I had one. Very low noise. No microphonics.
It is not encased in anything. No noise evident when the mounted tube casing is tapped, but I do get some microphonics when the treble tone control is tapped
I think the NuTube needs cushioning to avoid vibration microphonics. You know, like , that double-sided tape that's made of foam? If you put that on the backside of the NuTube before soldering it to the board, that might help reduce the effects of vibration.
Vox is using them on their new MV series of amps, and also Ibanez used it on a new Tube Screamer pedal, so there's definitely something they're doing to keep vibration from causing issues.
Maybe send another email to your friend at Korg asking for documentation on the evaluation board, as well as instructions on mounting the tube mechanically to a chassis and suchlike things?
Even if it's more of a show piece than an useful piece of tech, it's cool that someone is thinking about the future of tubes.
But if you put these as a preamp in a 120W head, then play stage volume, I bet you'll be in big trouble, regardless of the cushioning ;) I've had significantly less microphonic preamp tubes go haywire from feedback
But OK for a headphone amp, perhaps
I imagine it would be a feasible way to reduce vibrations by, like you said, solder it to a board with the foam tape cushion between tube/VFD and the board it's soldered, then solder that board to the main one with thin flexible wires instead of pins, and that board also foam cushioned. I can imagine a good enough adhesive will hold it all in place until something a lot more worrying happens to the unit, or if in doubt, some last case form of contention like screw posts that don't normally touch the board.
That would work against vibrations directly to the board it's attached to, but for sound induced ones there would need to be something else, don't think it would be horrible to think of something too (sound proofing ain't impossible after all)
Create an isolation chamber for it. Can you put a vacuum in a vacuum? 😁
I wonder whether the degree of microphonics varies depending on dimension (ie X, Y, Z axis)
I'm curious if something simple like wrapping rubber bands around it like the old tube "c-rings" would help the microphonics.
Piece o tape will do.
thanks brad..cant wait to see what this becomes...rings like a bell..
If you ever needed to make a video describing tube microphonics...this is it.
Regular vacuum tubes don't sustain like that. You get a "tink", but not that sustained note. It's interesting.
The Guitologist I’ve heard some tubes with that sustained ringing. They were cheap and broken, though.
The only noise I heard was the tape hiss. I'm here in my studio with Genelecs. Can't wait to see you building a guitar amp with it.
It's interesting how the microphony goes away once there is signal. I'm guessing the signal moves the grid and forces it to oscillate with whatever signal is in instead of the external vibrations. Is that possible?
I'm fascinated by that too. Signal def overpowers microphonics
No it´s rather that inbuilt camera AGC...hear the upcomming and raising noisefloor when the input signal vanished....typical AGC behavior. I bet the ProtoBoard is real quiet when hooked up to a nice spectrum analyzer instead of a poor camera audio input....
Yes. Tape hiss. Haven't heard that in awhile. How about a digital signal next time?
Lots of compression. Numbers 2 - 10 on the volume dial are pretty similar. You sure it's not the camera inputs Brad?
Would be interested in seeing a scope trace too while you're monkeying with it.
It´s probably from the manufacturing... I have a VFD that I intend to use as a tube and if I tap it and hold it close to my ear I can hear it resonating
Those tubes are wicked lol. Can't wait to see what you come up with.
bought the vox MV50 with these in it. If you travel a lot and want tube sound, I highly reccomend it.
There's no doubt that for guitar, we want to hear how these things behave when overdriven/underdriven/starved... all the ways around the block you might use with a 12ax7. Let's see what kind of a sonic fingerprint they have.
Full marks for using 'Blue Moon of Kentucky'...one of the first songs I remember my Mum singing along to.
Plinking one's finger on a vacuum tube while operating can do the same thing. Some folks even argue that it's all part of the tube mojo. Tube sockets that use rubber mounting grommets to deal with vibration are often employed when it becomes a problem or for reliability. Anyway, seeing it happen here is actually a very cool thing if you think about it - it let's one know that a nutube seems to behave very much like the tubes we all know. Thanks for vid - very interesting.
Great Video! Thanks for the great original content man!
With an amplification factor 25% lower than a 12AU7, you’ll probably need all four to make anything useful. Unless, you pair it with a solid state opamp, which is probably what Vox, Korg, and Ibanez have done. Good luck!
That's what I'm going to do for the first experiment, I think, pair it with an IC op amp or a transistor circuit.
The Guitologist how about using one of the jfet-as-triode circuits from Runoffgroove or BuildYourOwnClone. The voltages would be similar to what the nutube needs, the circuits themselves are identical to tube circuits (with a few resistor changes) and they have a ton of gain, and sound awesome.
It would still be cool to use say use 2 Nutubes to make enough gain to send enough signal to the power tubes.
The microphonics is due to the design of VFDs, which uses a long cathode filament only supported at its ends and it vibrates like a string. If you tap a VFD, it will make a ding.
You could build a amp using all of those just by making it step up the voltage slightly to each one where you would have a selector switch like A,B,C,D where each selection just ups the voltage slightly so that each a,b,c,d would give different gains ????
You were very nice of the critique there high microphonicks of this inprtavility device even in high fi it would need some serious isolation
I respect any man that likes the Stanley Brothers. My favorite group
Those monster rca cabel serie i think is directional.they should have an arrow marking from source to amplifer on them and is best is used in one direction.
I have been following these tubes for a while. They have been around for a whilem The unfortunate thing is that they are simply WAY to expensive, plus they don't have much gain at all. For that reason i designed a boost converter instead from a 12V supply (which you can use for the filaments).
Btw these nutubes have been used in Vox amps.
Btw. The noise is probably from the class-d chip. I am a developer myself and the board doesn't look very well thought out.
You don´t need gain from the tube (if you need gain get it elswhere), you need the distortion footprint from a tube by today that´s what it is all about....
The NuTube is designed to be easliy interfaced with semicons (OpAmps, transistors or FETs) not to be the only active thing in your design. and also that´s why they are build like a Dual inline package, for PCB mount...
If you want an all tube amp, go for the obvious, but not for the NuTube.
TubiCal .
That's totally true. So you need to have some kind of opamp gain stage in front of it. Which sometimes makes it difficult to fit with certain pedals etc. I am just saying this from a consumer point of view. Also it's a little more difficult to 'fine tune' your distortion footprint. (A lot of times you would combine different ones)
Very cool video Brad. I tried to see if someone mentioned this in another comment.. but the reason for the daughter-board (versus soldering the NuTube right on to the mainboard) is probably because Korg envisions modules of other types (maybe entirely different purposes) working with that main board (or already has). So, this design gives them the flexibility to design the main board without having to concern itself with the exact design of the chip that will be mounted to it. That is a common design technique in the digital industry. Also, regarding the microphonics, etc... this kit is probably what's called a "reference design." It's provided so many manufacturers that are thinking of using the NuTube can get going quickly and experiment with a wide range applications. When we do that in the digital industry, it's not mean to be perfect. It's meant to help with proof of concept. Sort of like a turnkey professional version of a breadboard set up that you might come up with in your lab. A manufacturer would very likely not include that entire package in their final product. For example, you can see how Vox made a daughter board of their own in one of the images here: www.voxamps.com/MVX150H. This daughterboard based design also makes it easy to replace NuTube in "the field."
Looking forward to seeing what you come out with. Love your channel man.
Your tape deck was making all that noise. I noticed it went away when you stopped it from playing.
I have 5 nutubes and I'm working on a low power amplifier board using all nutubes in the signal path. The complete pain in the arse with these things is that they are hot cathode, so you have to rethink all the usual circuits. Things like cathode followers and long tailed pairs also have both the heater current and cathode current running through the same path. So you need to re-work the usual equations. I have completely failed to work out how to do a cascode current source, since the cathode isn't floating.
this is new from Vox. a 150W head and a 150 watt combo using nutube
MVX150C1
VOX’s next-generation amplifiers equipped with Nutube, 150 watts of power, and a UK-made Celestion Redback speaker
150W amp equipped with a Nutube vacuum tube in both the pre-amp and power amp sections
Two-channel design covers a wide range of tones, from pure clean sounds to modern hi-gain
Combo amp features a UK-made Celestion Redback speaker
That blue glow reminds me of Cherenkov radiation. Those Korg Nutubes look the part too.
I didn't hear any noise using the vox mv50. anyway I'm really confused about the microphonic noises with vibrations because it doesn't happen with vox amps. maybe they blocked the nutube so well to isolate vibrations?....
Could be marketed as an electric triangle!
What about building the front end of a guitar amp up to the volume control and maybe a PL81 Line Timebase tubes as the output, the two small variable resistors are bias setting, it's a vacuum tube my friend but not as we know it.
I have one of the Vox MV50 AC amps. I've used it sitting on the tiny Vox 1x8 cab they make for it and also on a bigger H&K 1x12 cab and I noticed no microphonics or other noise. Works well for me. Sounds decent. Pretty loud, considering it fits in my hand, but that's probably due to the D-class output stage. Wish it had an effects loop. I've ordered one of those Ibanez Nutube based Tube Screamers but haven't got it yet. Based on my experience with the MV50 I'd expect it to work OK.
Who knew they 1940’s tech expert would be on the cutting edge 😝 great vid brad, can’t wait to see a guitar amp built with these.
Brad, this is a brand new thing and it's gonna have issues. I say, props to Korg for allocating a team and an ostensibly healthy budget to come up with something really next gen. I don't know what the specs are but it appears to be quite a departure from current tube tech and it should be really exciting to explore. It was cool of those forward-thinking Korg-folk to Fedex you a little nugget of future tech. Mess with it. Ponder it. Come up with something we've never seen. There must be a fix/workaround/use for those strangely musical microphonics.
I do realize that I am posting a reply to a situation that is nearly three-years-old. Whatever.
Having looked around for this tech in the present-day (lol), it doesn't seem to have gotten much traction. Maybe there are so many digital options that a new (weird-looking) tube seemed redundant. I hope somebody comes up with a novel way to take advantage of these little glowy sticks of funky Japanese tech. The Nutube amp that Toshi Hiketa plays at the 2015 NAMM on their Gallery page sounds great. And it's tiny... But then so is a laptop. [sad face]
It’s a pre-amp? A final? Does it have effects or EQ or sumthin or just a volume upper-downer? I guess I don’t understand the application...
I've had a Vox MV50 AC for a couple of months now. I've played it pretty hard, usually on top of a cabinet with the "deep" switch engaged. I haven't noticed any microphonics or undue hiss (like when using a string of pedals). I'm not going to open it, though. It ain't broke so I'm not going to fix it.
Can't wait to see what you decide on building. I'm not sold on them. Hope you build a preamp section and a/b it through an effects loop.
I'm with you on the mircophony, sounds like a major problem. It's at a pretty high frequency though, so maybe a sharp LPF would be an option to deal with it (for a guitar distortion, would be horrible for HiFi of course)?
A few critical remarks: Firstly, this is a evaluation board, I'm quite sure it's not meant to be super HiFi/low noise/etc. . If you actually want to test noise levels, why not hook the output up to a scope while nothing is fed into the input (or with a tone generator on the input). In the current setup, noise might be coming from any of the sources, why blame the tube? The IC is probably an op-amp (acting as a buffer), which might also be noisy.
I'm not convinced by these things either. Have you tried curve tracing one? Would be interesting to see some realistic test results, data sheets are usually overly optimistic for modern tubes. Properly testing the tube will also give you a much better idea of what component values should be ideal for your tubes.
In conclusion: would be super interesting to see some test on these things!
Man I wished I knew more about this stuff. Completely fascinating!
Looking forward to the build with these.
I think the purpose of Nutube is to be a viable alternative to vacuum tubes which we all know are highly inefficient. I am very happy to see in this video that Nutube works very well considering the audio source is from an old cassette player. Yes it is microphonic but even the microphonic sounds really pleasing and I believe Korg can still resolve this "issue".
Overall, I can see Nutube dominating not only the amp business in the future but also the hi-fi arena whilst being environmentally friendly :)
Cheers from New Zealand!
Perfect for Christmas music! :D
It is definitely an advantage over the other tubes that it can be operated at semiconductor like voltages and currents. Also the very small heating power for the cathode is impressive. I think, the problem with the microphonics can be solved by an internal design improvement which provides more mechanical damping to the structures and less weight and more spring constant to the control gate suspention to shift the frequency above the audible frequency range.
It would be interesting to use the double triode as a differential preamplifier stage to arrange a negative feedback loop in order to improve linearity.
Vox is making a combo and head 150watts ,nutubes and their in both sections. Mvx150 is what it's called I think
Anyway, the compression effect you got by stopping the tape was smooth enough (sounded like typical tape compression), it didn`t sound bad entirely.
Hey man.. you plugged the headphone out into a camera that is more than likely mic or line level in. Of course it added noise, you added an extra gain stage. And no offense but it went microphonic on the right side only? The side you messed with the bias pot coincidently. I’m just pointing this out because i think these are fascinating and want you to make more videos on these.
Use chip sockets to attach them instead of soldering them directly into your circuits, and you won't have to worry so much about running out of them. That looks like a normal 0.1 inch pin spacing, in which case a socket for a 6502 or 8088 would have plenty of pins to work with, using just one side.
The tap test sounds like the closing bell for the stock exchange, or the beginning of _YYZ._
I must say that is shockingly microphone but they made a pedal with one that gets stomped on. Very interested to see where you go with this.
Hey Brad, did you ever end up building anything with these nu tubes ?
Not yet. Can't seem to find time yet. They're still on the agenda.
Cool to see these things in action. I'm not holding out much hope, but it will be fun to watch.
It would be cool to mix this with tubes, the nutube actting like a 12au7/12ax7/12at7 as a preamp driving the signal to the power tubes.
I don't know if the nutubes would push enough signal to the power tubes.
Is this a development in response to Thomas Blug's Russian nano-tube he uses in his 100w pedalboard amp1 Bluguitar?
With the microphonics it's displaying I can see why its being directed towards headphone amps. Anything more than that and it's going to need to be heavily damped. That being said it does sound pretty good.
not sure but I think those two mini pots are to lower the gain into the tube in order to lower micro phonics
Ill look forward to seeing what you can do with them. Cheers Brad.
I am pumped. I want to build a stereo setup with these.
Any idea of the cost structure involved? It'll have to be awfully inexpensive to be cost competitive with existing traditional products.
Wow, that's some wicked microphonics
1. The small chip on the bottom near the volume control is just an OpAmp. 2. The 3 prong chip that looks like a huge transistor is a simple voltage regulator. 3. Your camera automatically adjusts the volume according to the level of the ambient noise. Turn off auto sound level on your camera and that should do the trick :)
the recommended way to mount the device completely ignored so basically you're banging the elvelope to pcb. it's suppose to be soldered at the tips of the leads and put some thick sponge underneath, like all VFD's are usually mounted and it wouldn't ring. that's why what little circuit board is provided. this is like holding a normal tube in the mid air, banging it with a hammer and saying that it has bad microphonics.
Brad, as long as the nutube does not get hot, you can isolate it easily enough. Do some flying leads between the boards and tape to a piece of foam (that is as long as it does not get too hot and make the foam burn or conductive). I am thinking like the foam that pickups are mounted in, something like that. That will likely fix all the microphonics. A dab of silicone might hold it to the foam and also hold the foam to where you are mounting it. Hope that helps.
Interesting, thanks. I wonder how Ibanez damped vibrations for their Nu Tubescreamer? Hard not to create vibrations in a stomp box when you stomp on it. It'd be cool to see a tear-down of the Nu Tubescreamer.
Interesting that no documentation was provided along with the circuit boards...
Have you built any overdrive guitar pedals using these Korg NU tubes or made a small amplifiers using these Korg NU tubes? because I want to see a video of you fixing all the microphone issues and white noise hissing issues to know how these things work. Since you got 4 NU tubes you can build circuits now.
And make another amp using the phosphor display off of an old VCR or microwave oven for giggles. It's likely this thing would be more comparable to those than traditional vacuum tubes.
That ringing pinging jay be the reason they made the Vox heads and pedals but no combo Amps that I have seen yet .Cant wait to hear a combo .
They've got some combo amps out
voxamps.com/VX50Series
Mmm, imagine some bass going through a combo and the interesting microphonics you could get.
Also
voxamps.com/MVX150
So put a gate on it. It doesn't seem to be microphonic when there's a signal, so when there's no input just cut the output.
I don't know about this.. I would say that I liked the idea of Seymour Duncan Twin Tube with these little - 6111 dual triode tubes
Might be an interesting component in a compressor. Maybe run it into an old diode bridge style circuit. Might be a fun very non transparent effect.
Hey Brad... any updates on the NuTube? Did you figure out a project to try? How about some type of foot pedal or a preamp? Maybe an onboard distortion in the cavity of a guitar? Hopefully you figured out how to reduce the microphonics? Keep the vids coming... love 'em!
I couldn't hear any microphonics once there was any signal going though. So, I'd want to see what it's like without any compression. The only background noise I could hear was a hum. Not sure where that's coming from - that might be the power supply.
You've probably seen amps where the socket for the first preamp tube is mounted on rubber grommets to reduce microphonics. Maybe there's a similar way to shock mount the NuTube to achieve the same effect?
Did you ever get the ringing to stop? Sorry so late. I have some Dynamat. I could send you a small piece. Installation and retest would take less time than connecting to you recording rig. Just a thought. Lmk... ;)
Did you had the chance to desing something around it? I can't find a follow up video on your channel! Cheers!
Am I stupid or is there a Cap missing on the Nutube PCB?
Link to box cutter?
Those trimpots are probably bias. Also, I've heard that EF86's are noisy, but this is taking it to a whole other level.
Vox have a 150w head and combo already on sale.
Where are the other videos for this. Fant find them
Just bought the Vox MV50 ac amp that has these tubes in it. Sounds great. Seems like pretty solid piece of kit. Looking forward to what you do with the NuTubes.
It has been a year and have you done any additional experimenting with the NuTube?
Dude, make a doorbell that dings when feet walk up the path,,, hands free doorbell. Sweet.
I would say that Nutube needs to isolated or sitting on a suspended shock absorbent material, and that thing will be golden.