From what you describe I can conclude that your DAC is not good. You said you use DIY wireless DAC with tube output. I do not know what wireless mean in this context, but it is not important. I also know do not like any tube output stage in DACs, I have written about it extensively. Anyhow, my rational to blame your DAC is following: the sonic changes you describe shall not take place if your DAC is able to drive your power amp properly. It is not only about output impedance. Something in that DAC’s out stage does not work properly as a good preamp much not make a difference as you witnessed. With very good preamp you might have a little better dynamics and slightly better bass but it shall be all. If you witnessed so dramatic soundstage change, change in detail and speed and higher extension of HF then you are just way beyond of definition of preamp transparency. Are you sure that what you observe was not change in cables or something like this? As I said above, if I got the result you did then I would revise what my front end outputs. Find another DAC, of phonostage of CD player with DC-coupled SS output stage, it shall not be any good devise but any consumer unit would do. Do the same experiment with insertion of your preamp. You most like will not has the same difference. Rgs, The Cat |