I want to make audio amplifier and dac,maybe even microphone pre-amplifier with as low noise as possible,atleast -120db.Lots of expensive audio gear is audiophool c.rap,but there are also very good stuff out there,especialy the high end solid state studio equipment that have impressive low noise powersupllies.
My problems is that I have very limited budget,only instrument I currently own is Voltcraft VC890,its good modern 60000 count DMM with nice oled display and 0.03%dc acuracy.I plan to buy one low noise oscilloscope,either Siglent SDS1102x or 12bit Owon XDS3072a for 450 euro.
My question is,what kind of electronic gear is used to measure these low level ripples and noises? What should I get? I dont want to spend more than 300euro on top of the new 450e scope,so my absolute max is 800e,keep in mind only thing I have is one handheld DMM.If possible I would like to spend even less than that. I would like to know best new option,and best used option,I fear buying things out of warranty,but if its only way to satisfy my requirements I have no other choice within my limited budget range.
I am new at electronic engineering,I have been learning only 4 months so my knowledge is limited,I have been thinking agilent 34401a used could be good.but again,I am not sure what I really need,and here in eu its rare to see it being sold,shipping from US is expensive and I fear it will break since its old and that would be catastrophy for me since my income is very limited.Also as I was reading about 8.5 digits dmms ( out of curiosity,I cant afford those lol ),I saw something about microvolt DMMs from keithley,also I saw some instruments dedicated to ac rms measurements,is any of what I mentioned good for my purpose?