Quote:
Originally Posted by NeilPeart
As much as I enjoy the K1000/T-amp combo I fear the AKG headphone has dragged me into a quest which I did not wish to embark upon – I feel the K1000 almost NEEDS tubes.
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I am not surprised that you came to this conclusion.
After 100+ hours of break in, including 30 hours of listening, I now feel comfortable discussing the sonic properties of K1000 and the effect of amplification.
DAC1 is on the bright side of neutral, so are T-amp and K1000. Put these three together, you get very detailed and fast sound. But the tonal quality is a tad too bright. Looks like a tube might be valuable addition here, doesn't it?
Fortunately, I also have a 30W Jolida hybrid integrated amp sitting around (replaced by T-amp in my speaker system). It uses 12AX7 and LM1875 OP-AMP (also in 47 Labs Gaincard). Trying TNT-selected Chinese tubes and Yugo, I prefer Yugo's its warmer but less detailed sound. Yugo 12AX7 takes away a little bit of detail and blur it out. The resultant blur to my ears appear similar to the natural decay of sounds in a spacious hall. It gives a sense of distance and adds more space/air to instruments. Since K1000 is detail king, sacrificing a bit of detail for a pleasant decay brings overall improvement.
Having several adapters at hand, I could use DAC1's XLR (pin 3 floated), RCA and headphone jack to drive the downstream amps. After some un rigorous testing, connecting to Jolida with RCA out and using variable output with volume pot at 3 o'clock sounds best to my ears. I also think using headphone jack to drive T-amp gives a warmer sound. In this case, maxing T-amp's volume and using DAC1 as preamp sounds better. Again, YMMV.
Is DAC1 really too bright a source? I don't feel that. Not having another hi-end source at home, I have t resort to my SACD/DVD player as a reference (original MSRP $1000). I tend to believe a decent SACD palyer playing SACD can match any CD player in terms of hi-freq smoothness. Telarc's 1812 hybrid SACD is a great demonstration of the smoothness of DSD recording compared to CD. I am intimately familiar with the difference between the two layers after listening a hundred times. SACD via Sony sounds smoother than CD via DAC1, but through Jolida and K1000 the difference almost seems to disappear--I am getting some very smooth CD sound here [Edit: Smooth for CD standards. Still not as smooth as I would like it to be, as in live music.] But through Jolida and speakers the difference is still quite big. I guess Jolida and K1000 has great synergy. T-amp clearly drives my speakers better than Jolida. Incidentally,
LM1875 suffers less THD with higher impedance loads (8 vs 4 ohms), and I wonder if a 120 ohm load would cuase even less distortion?
As for bass, K1000 has a -3dB point at 40 Hz. Clearly it does not have ideal bass extension and it does not rock you hard. K1000 does not try to compensate by increasing midbass input, which is good IMO. In calssical music and jazz, clean and tuneful bass is more important than body-shaking bass, so I don't complain. Tried using subwoofers but it did not work too well. My subs aren't very fast, tunable cutoff filters aren't steep enough, and my small room creates midbass standing wave modes. Listening to K1000 with subs gives me deeper but muddier bass, and the blend is not seamless (worse than K501 + sub). I am fine with K1000's own bass, so no plan of adding better subs in the near future.