Schubert, you might check with the manufacturer to see if removing and installing tubes while the unit is on is a problem. With our preamps, as long as you take certain precautions, its easily done. But I can imagine not all preamps are like that.
But listening to tubes is the best way to grade them, however tedious.
You might also check with the manufacturer to see if there are particular tubes that contribute more to noise. You may not have to be swapping all 8 of them to sort it out!
But listening to tubes is the best way to grade them, however tedious.
You might also check with the manufacturer to see if there are particular tubes that contribute more to noise. You may not have to be swapping all 8 of them to sort it out!