I pretty much agree with Mezmo's observations, and would just add that when the 6 tubes in my pre-amp (SF Line 2SE) get to be 12-14 months old, music quality starts getting a bit hard, bright, strident, and progressively more fatiguing. I keep the pre-amp in standby when not in use, and this uses up some tube life, and then I listen to music 3-5 hours per day.
With new tubes, the hardness and slightly fatiguing music character goes away. I've used this pre-amp over four years now and have changed tubes several times (not counting experimanting). Perhaps this (short)1 year tube life has to do with the stock Sovtek 6922 tubes I had been using. BTW, I recently switched to a set of NOS Sovteks and realized a significant improvement in music quality-- hope they last longer than the stock tubes. Cheers. Craig
With new tubes, the hardness and slightly fatiguing music character goes away. I've used this pre-amp over four years now and have changed tubes several times (not counting experimanting). Perhaps this (short)1 year tube life has to do with the stock Sovtek 6922 tubes I had been using. BTW, I recently switched to a set of NOS Sovteks and realized a significant improvement in music quality-- hope they last longer than the stock tubes. Cheers. Craig