Saw this mentioned in passing on a YouTube video and thought it worth bringing up here -

https://diyaudiostore.com/products/korg-nutube

I'm not much for audio technology (as my ears don't really work), but thought it might be worth bringing up in case anyone else might be interested.

 

I guess this is sort of interesting, but given the current state of semiconductor technology I see no benefit to be gained by using the product. If I use low-noise devices with frequency response of at least a few megahertz, and avoid nonlinear operation it should be simple to keep any distortion far below what I can hear, or conveniently measure. (THD less than 0.01%) That is at least 20dB below what a very trained ear can ever detect. ( only those who can clearly detect the distortion added by ten feet of #14 plain copper lamp cord can hear this level of distortion)

 

I don't see the point. There are vast quantities of new-old-stock valves available for anyone who wants to experiment with the technology for as little as a dollar each, and you can get a brand new ECC83 (12AX7) for a quarter of the price of the 6P1 although it might be made in Russia.

 

Me either, but this was apparently of a sound chip retrofit kit that was marketed to 8-bit era computer enthusiasts who were also audiophiles (and if I recall correctly, with a matching price tag).

 

The big question I have is how many audiophiles are currently designing tube type amplifiers? That seems like a rather limited market.

 

Don’t forget the guitarists!

 

Don’t forget the guitarists!

It is true that some guitar players seek to have a "tube sound", but my guess is that they are not the ones who could actually design a tube amplifier.

 

The big question I have is how many audiophiles are currently designing tube type amplifiers? That seems like a rather limited market.

I would not consider myself to be an audiophool.
I do play guitar. My real interest in building my own guitar tube amp was:
a) the geek effect,
b) I wanted to give it a try because tube circuits are very simple and forgiving when it comes to grid bias and distortion,
c) I had all the parts available to do this, except for the output transformer.

 

d) trying to understand what makes people say they prefer the "valve sound" (and after a lot of measurements resigning oneself to the fact that people must actually prefer a distorted sound)

 

The attraction to valve/tube sound is easily understood and well known as "warm".
When solid-state amplifiers clip, they clip hard, producing square waves giving rise to odd harmonics.
When tube amps get into amplitude saturation they go into non-linear mode, giving rise to signal compression. This gives it a warm or mellow tone without the harsh distortion of solid-state amplifiers.

 

The distortion became a trademark and signature of some kinds of music. HARD rock and Acid Rock, and some very talented musicians playing with some terribly distorting amplifiers because they had nothing better.
Certainly only some types of music benefit from that distortion.
And certainly tubes do distort with rounder clipping, as opposed to the very sharp cornered clipping of tube amplifier circuits. But there are ways to come close to the same sound with solid state devices.