Originally Posted by marshallmole
Okay now the T1s have arrived, and it's just as I expected, that my NFB10SE has enough power but not enough refinement for their full potential. I'm hoping to add a touch of warmth with an amp, will the SEX be able to do that? I fear that the Crack would be too warm for my taste.
Also what kind of advantage would I get with C4S upgrade? More refinement in mids? I read Loquah's review but didn't get the gist about the effect of C4S...
I'm currently considering the SEX and Yulong A18. Thanks!
The C4S is refined and perhaps a tiny bit warm, but not as much as other tube amps I've tried.
In terms of the C4S, I can only describe what it does as bringing all the music into sharper focus (including the mids). Imagine looking at an image through your camera that is just a hair off perfect focus (so little that you can't tell until it's made perfect) and then adjusting it so that everything suddenly becomes even sharper and clearer. That's what the C4S does - it just makes everything about the S.E.X. significantly better, but it doesn't alter the signature at all. So yes, refinement in mids, but also in treble and bass. The idea of the C4S (and Speedball for the Crack) is to apply a higher load to the tubes which helps them to operate consistently at stable, peak performance so you're just getting the best possible sound out of the circuit. That's why it doesn't really change the sound signature, but rather just refines everything to be better at what it already did. (Or at least, that's my layman's understanding)
As for S.E.X. vs Crack. A modded Crack with a better attenuator / volume pot and a nice set of output caps can sound exceptional, but will still have a more intimate presentation than the S.E.X. I wouldn't worry too much about warmth, because the Crack can easily be tuned with caps and tubes to be thick and creamy or airy and transparent (but still with some lovely tube warmth). I would probably base my decision on 2 things:
- Are you willing to modify the Crack after you build it (i.e. change caps, attenuator, etc.)?
- What sort of presentation do you like? 3D, but intimate (Crack) or spacious and open (S.E.X.)?
If you're not wanting to mod the design, you will definitely find the S.E.X. to be superior (IMO), but with about $150 worth of mods I would say the Crack (+Speedball) easily can hold it's own with the S.E.X.