Nuvista Tubes - General


May I have opinions please on the pluses and minuses of Nuvista tubes versus vacuum tubes? Supposedly and from the basic homework I've done, Nuvista tubes purportedly offer high reliability, low microphony, low noise, consistency, and small size compared to their vacuum counterparts. So what's the down side? 
128x128gdhal
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No, directed at all tubes, unless direct output coupled.

I don't believe anyone has made a tube amp/preamp that is direct coupled (no caps or transformers in the signal path) from input to output, like you can with solid state.
The KSS OTL was direct coupled from input to output. You can do it, you just have to jump through some hoops.

I don't think direct coupling is a good idea for either solid state or tubes, because the timing constant of the amplifier goes lower than its power supply. At that point, its possible to modulate the supply, which in turn introduces IM distortion.

We limit the bandwidth of our amps to 1 or 2 Hz for this reason, but we do employ direct coupled inputs and outputs.

George, is your statement about a hybrid being a "sales pitch" in your opinion specific to MF, or in general and applicable to any hybrid amp manufacturer?

I just look at where he used them in the Trivista sacd, that they could be bypassed and probably get better sound/transparency without any circuit design negatives. And that they were maybe from army surplus, and just used to "maybe" give a product more cred/appeal to the "tube set". 

Same what I saw in the MF A3-24 dac a good dac, but two massive power supply chokes (army surplus?) on already very nice super low noise, very stiff low impedance solid state power supplies, what for?? just to make them not stiff again??? Again appeal to some that love chokes in tube equipment?

Cheers George   
I just look at where he used them in the Trivista sacd.......
.....Same what I saw in the MF A3-24 dac...........

@georgehifi

I take this to mean your statement about a hybrid being a sales pitch ** is ** specific to MF.

I take this to mean your statement about a hybrid being a sales pitch ** is ** specific to MF.

No there are others that do it, just to get the Tube guys interested as well.
Just like McIntosh throw an output transformer on the end of what "could be" perfect good solid state amp, absolutely no need for it if the solid state amp is "done right". Try putting an output transformer on the rear of a Gryphon, Krell, ect, and see what happens to the sound. 
 
Cheers George