AN Niobium versus Tantalum resistors?

UPDATE:

I was concerned the Niobiums were too tubey and compressed sounding, so I swapped all the resistors to Z-Foil. There was instant gratification of low noise and high resolution, but after several hundred hours they did sound thin and there was an extremely "metallic" felt-texture. Tingy, metallic, pingy. Acoustic guitars and flutes and especially vocals were metallic to the point of sounding like my loudspeakers became tin cans. It was unenjoyable for everything but showing off slick sounding techno music.

In this case, I would prefer Takman or a mix of Z and Takman, because Takman have crispy and gross highs, but are FAR more musical overall than Z foils. 

However..

I put back in the Niobiums which had 150 hours on them, after AN reassured me I should continue burning them in.

Now at over 300 hours, I can say the sound is fantastic. They became tighter from bass to treble, with no slowness or compression, but much more music comes through than Z-foils. The felt-texture which began woody and waxy now is more like "felt" (think of the felt hitting a metal string in a piano), which is very low fatigue. Acoustic guitars sound natural, bass is warm, highs contain a ton of information - tambourines and cymbals are rich and natural. Imaging is easily as precise as the Z-foils, but with an analog feeling and not metallic.. overall a perfect resistor! Just keep in mind they really do take well over 200 hours!

While I was concerned at their ’tubeyness" at first and combined them with Z-foils, I am ordering more for the circuit and think I can go full-Niobium. Just bear in mind its a very long burn-in.

@clustrocasual - Thanks for the updates. Have you tried the silver tantalums? 

Are you using the silver Niobiums? What wattage parts are you using? 

I've been using the silver Tantalums, but haven't tried the Niobiums.

They are .5W because of space issues, I was not able to go higher. I use standard Niobium, which are higher resolution and fuller sounding than Z-Foils, as a comparison. They are the highest resolution resistor I have tried so far and the tone curve feels natural and nothing weird, no rhodium/silver tilt etc. Just a great improvement to the Takman sound I was getting before. You lose a touch of "exciting" metallic felt-texture, but its worth it for the naturalness of the music. And that part is totally subjective anyway.

Have not tried tants but read many reviews of them before deciding. There’s a website which said the Niobiums are "musically" on a higher level than silver tants, although the silver tants may give some improvement in certain areas.

I want to try the silver Niobium this summer. At first I thought I needed them because these began VERY warm and dark, even at 100+ hours. Then they shifted bright and brittle. They went back and forth until you get both warm and top end, but then they are sluggish. Thats when I removed them. But when I put them back, the next 150 hours cleaned and tightened up the sound and they are super solid now. Even bass-heavy techno music sounds as tight as metal resistors, but like a flood gate of music and transparency comes out.

your results with full Z-foils mirror my own. Ideally I use a mixture of Z-foils and Takman metals, with a few Caddock MK132 (very full, bold and assertive) and Shinkoh tants (musical and finely textured) thrown in for flavour.

The MK132‘s are very good at balancing the  Z-foils in circuit.

I recommend replace one position of either the Takman or Z-foil with Niobium. I tried a few combos of this.. small differences of these locations, but in all cases the improvement of Niobium was great!