it is indeed the output coupling cap. Since the impedance of a cap is 1/j-omega-C, we want the cap as large as is sonicaly reasonable. Forget about j and root negative 1. It is the real part of this we will look at.
At 20 cps, omega is 2*Pi*20 radians per second and C is 7.5 * 10^-6. this yeilds 1061.03295 Ohms. At 40 cps, it is half that, and at 80 cps, half of that. This is close enough to the 10:1 ratio of input impedance to output impedance which keeps us from rolling off too early, even with a 10kOhm SS amp. For a 100kOhm Valve amp and several tens of pF of cabling capacitance, we're still good. regards, Douglas
Posting Rules
Members
Search
Help
Register
Login
Get a T-Shirt!
