i am searching all over for this and i probally missed it. lets say i have a device that i bought that does 20db of boost. now what does this relate too. lets say as an opamp.. what would a opamp version of this be gain wise. woudl it be like around 20 or 200 or am i off track here.
edit.. ok so according to the calculator at jacks site, would this be correct a voltage gain of 10 so is that like i have a mxr dist type pedal set up for clean, and have the a 100k feedback loop resistor and a 10k going to ground.??? sorry i have been up way too long, i am probally not lookin at it logically.
you've got it right:
10X = 20dB
100X = 40dB
1000X = 60dB
DB of voltage gain is numerically equal to 20 times the log to base 10 of the voltage ratios.
Example: You get ten times as much voltage out as you put in. What's the DB ratio?
Answer: ratio is 10:1, or 10. Log 10 (10) = 1 DB=20*log10 = 20*1 = 20
Example: you get two times as much voltage out as you put in. What's the DB ratio?
Answer: ratio is 2:1, or 2. Log 10 (2) = 0.301029995 DB=20*0.301... = 6
DB adds, since it is a logarithm. If you have two boosts of ten, you get +20db plus another 20db, or total gain of 40db. Working backwards, this is a gain of 10 to exponent of DB gain divided by 20 or 10 to the second power, 100x.
Example: you get out 7.4 times as much as you put in. What's gain in DB?
Answer: ratio = 7.4 Log 10(7.4) = 0.869... DB = 20*0.869 = 17.38 DB.
Power DB is only 10 times log 10 of the power ratios, so while half voltage is at -6db, half power is at -3db. The math works out that way so everything makes sense. Mother Nature gets her shorts in a knot if you try to change the Rules.
thanks both of you.. :) that helps a lot i was lookin at one of the emg boosters cause they are trying to hook up their mistake. i had an old one and it was the same specs so anyway i thought i would check to see if it was worth it.