I am now distributing the Korg NuTube 6P1 to DIYers, experimenters, and small OEMs.
For those of you that haven't heard of it, the NuTube is a newly developed, low voltage tube. It is a dual directly-heated triode. It is a very low power device, consuming only milliwatts of power.
You can get more information about the 6P1, including the full datasheet, at NuTube.US.
Also available is an evaluation board and other hardware to make using the 6P1 a little easier. These are also described on NuTube.US.
Sales will be done through an eBay store: NuTube.US Store | eBay Stores. Please be patient, it seems eBay takes some time to propagate the listings so that they show up in the store and in searches.
Thanks!
Pete
For those of you that haven't heard of it, the NuTube is a newly developed, low voltage tube. It is a dual directly-heated triode. It is a very low power device, consuming only milliwatts of power.
You can get more information about the 6P1, including the full datasheet, at NuTube.US.
Also available is an evaluation board and other hardware to make using the 6P1 a little easier. These are also described on NuTube.US.
Sales will be done through an eBay store: NuTube.US Store | eBay Stores. Please be patient, it seems eBay takes some time to propagate the listings so that they show up in the store and in searches.
Thanks!
Pete
eBay is still indexing...
eBay is taking forever to get these items properly indexed.
In the mean time, you can directly access the listings:
Korg NuTube 6P1 - low-power triode vacuum tube | eBay
Bare carrier PC board for Korg NuTube 6P1 | eBay
Evaluation board for Korg NuTube 6P1 | eBay
Assembled carrier board for Korg NuTube 6P1 | eBay
eBay is taking forever to get these items properly indexed.
In the mean time, you can directly access the listings:
Korg NuTube 6P1 - low-power triode vacuum tube | eBay
Bare carrier PC board for Korg NuTube 6P1 | eBay
Evaluation board for Korg NuTube 6P1 | eBay
Assembled carrier board for Korg NuTube 6P1 | eBay
Looking at the data sheet I think this thing is intended to be a "tone" generator.
I wonder if it is even capable of driving a circuit on its own?
They show a sample circuit with a single FET input and output and this tube PARALLELED in between.
Novel and interesting; they look to be useless for the home audio market and at the price an expensive novelty at that.
As usual I would welcome being proved wrong.
I wonder if it is even capable of driving a circuit on its own?
They show a sample circuit with a single FET input and output and this tube PARALLELED in between.
Novel and interesting; they look to be useless for the home audio market and at the price an expensive novelty at that.
As usual I would welcome being proved wrong.
I guess one could make exactly the same comments about a 300B tube...
I do view it as a "signal processing element" more than an amplifier. It has pretty low gm. If your goal is a low distortion amplifier, regular tubes and opamps are far better.
Korg's main application for this is musical instruments, not hi-fi.
That said... I have built both a headphone amp and a class-D hybrid amp using this device. In both cases they are set up to ADD some even order distortion to what would otherwise be a very low distortion amplifier - essentially to make a solid state amp sound like a single-ended tube amp, without high voltage supplies.
Whether this is a good thing or bad thing is up too the listener - I won't debate it. But why would somebody want to listen to a single-ended 845 amp when they could listen to a class-D amp that has far better specs at 1/10 the cost?
Pete
Nope. The gm is too low, so it generates too much noise for a phono preamp.
As much as the tube purists will disagree, for me, sometimes, opamps are best...
Pete
I have not seen data from Korg on it yet. My experience so far with about 20 headphone amplifiers has been that they are pretty close unit to unit. I am using fixed bias.
I did allow for gain adjustment, mostly to make sure that the channels were matched. Without adjustment they were within a dB or so.
Pete
I did allow for gain adjustment, mostly to make sure that the channels were matched. Without adjustment they were within a dB or so.
Pete
Yes, a couple of things. I am building a commercial headphone amp that uses the Nutube: The Sangaku
I also designed and built a hybrid class_D amp (Nutube driving class D) as an experiment. I haven't published anything on that yet.
And, I am selling an evaluation board through the website (NuTube.) You can see it (and download the details) halfway down the page.
Pete
The Nutube is definitely a bit microphonic. Korg has experimented with several ways to try and mechanically isolate the tube from the PCB, including connecting it with thin wires and mounting it with a rubber sponge.
I have not seen the case that you showed, so I'm not sure how it works.
In the headphone amp I designed, I did not isolate it from the PCB. You can certainly hear a noise if you tap the PCB, but I don't think it is excessive.
If you were going to use the Nutube in a low level signal application (like a microphone or phono preamp) you would probably need to address it.
Pete
I have not seen the case that you showed, so I'm not sure how it works.
In the headphone amp I designed, I did not isolate it from the PCB. You can certainly hear a noise if you tap the PCB, but I don't think it is excessive.
If you were going to use the Nutube in a low level signal application (like a microphone or phono preamp) you would probably need to address it.
Pete
Hello Pete
On official Korg Nutube site they write about adaptors for minimise microphonics probably available in the near future.
This ones show on the photos are small run no official version ready we can buy on the market in Japan.
Plexyglass cut with laser machine
Best regards
Christophe
Attachments
Pete,
i received the tubes in good condition,thanks.
Now my plans and if anyone like to ad some ideas, please do.
My son is a DJ here in the Netherlands and he use a 6n16 tube buffer between his mixer and the active filtering for the main speaker amps for years now. We did various testing with and without the tube buffer but almost every body liked the music with the tubebuffer. The 6n16 buffer is a very clean buffer with about max 0,1% distortion.
Now i like to build something like that with the 6p1.
Mixer output is 1Vrms asymmetrical. I will lower that signal with resistor devider to 40mV and use this as input for 6P1. The 6P1 amplifies 5 times at 12V anode supply. This 200mV output i send to a lm4562 opamp with lme49600 buffer (like the wire design ) with 20 times amplification. Now i have 4Vrms signaal strong enough to drive long cables on stage. Playing with the bias give me the possibillitie for searching best operating point.
The above setup works also great for headphone amp design.
i received the tubes in good condition,thanks.
Now my plans and if anyone like to ad some ideas, please do.
My son is a DJ here in the Netherlands and he use a 6n16 tube buffer between his mixer and the active filtering for the main speaker amps for years now. We did various testing with and without the tube buffer but almost every body liked the music with the tubebuffer. The 6n16 buffer is a very clean buffer with about max 0,1% distortion.
Now i like to build something like that with the 6p1.
Mixer output is 1Vrms asymmetrical. I will lower that signal with resistor devider to 40mV and use this as input for 6P1. The 6P1 amplifies 5 times at 12V anode supply. This 200mV output i send to a lm4562 opamp with lme49600 buffer (like the wire design ) with 20 times amplification. Now i have 4Vrms signaal strong enough to drive long cables on stage. Playing with the bias give me the possibillitie for searching best operating point.
The above setup works also great for headphone amp design.
Last edited:
Yes, this should work fine. You can experiment with the bias and plate load resistor on the 6P1, and also try changing the input attenuator and output gain of the opamp stage.
I'm thinking one could use a dual linear taper pot and connect one channel as the input attenuator, and the other as the opamp gain (but connected "backwards"), and have one single "distortion" control? I need to try that...
Pete
I'm thinking one could use a dual linear taper pot and connect one channel as the input attenuator, and the other as the opamp gain (but connected "backwards"), and have one single "distortion" control? I need to try that...
Pete
