Re: How to design a passive single-network RIAA (two tubes)

Thanks. I spent a long time on this solution on Sunday. It was beneficial for me because I actually calculated the precise ratios that are needed for an "ideal RIAA" in this topology. The transfer function is a little hairy as it is, with a zero and two poles in the denominator that must be solved from a quadratic equation. I had to program my calculator to iterate the answers. But now I know what they should be instead of just guessing as I was doing. A simulator like Pspice lets you get real lazy and you don't derive the exact relationships that pure math does. So I never knew these ratios until just now. I looked back and saw how I can make my designs a bit closer, and the initial chosen values can now be very precise.

What the simulator does provide that this doesn't is add in all the model components and get a real overall picture of the output compared to an ideal RIAA, like what happens when the V2 grid resistor is chosen and the coupling caps and the Cgp capacitance effects, and the autotransformer step attenuator loading on this output stage, etc. The math balloons exponentially with all those added variables. But the intuition for why something is chosen is not well understood. So the basic math and the rules of thumb are capable of getting you dang close right up front and you understand more about the problems of getting there exactly.

Kurt

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Follow Ups Full Thread

Topic - How to design a passive single-network RIAA (two tubes) - Kurt Strain 20:40:10 03/24/02 (21)

How to design a passive single-network RIAA (two tubes), 2nd draft - Kurt Strain 21:41:54 03/26/02 (0)

Re: How to design a passive single-network RIAA (two tubes) - Fred Humphrey 09:02:12 03/26/02 (1)

Re: How to design a passive single-network RIAA (two tubes) - Kurt Strain 09:44:11 03/26/02 (0)

The Dowdy Lama smiles on Kurt - Jim Dowdy 19:35:54 03/25/02 (0)

Re: How to design a passive single-network RIAA (two tubes) - Paul D. Scearce 11:14:50 03/25/02 (1)

Re: How to design a passive single-network RIAA (two tubes) - Kurt Strain 03/25/0212:45:38 03/25/02 (0)

Dumb question # 1 - Ivan303 09:24:34 03/25/02 (1)

Re: Dumb question # 1 - Kurt Strain 10:43:31 03/25/02 (0)

Audio Engineering Society's preprint no. 1424 (n-3) - Steve 08:45:24 03/25/02 (3)

Re: Audio Engineering Society's preprint no. 1424 (n-3) - Kurt Strain 10:16:06 03/25/02 (2)

Just wanted to check as...... - Steve 12:49:16 03/25/02 (1)

Re: Just wanted to check as...... - Kurt Strain 13:22:28 03/25/02 (0)

Re: How to design a passive single-network RIAA (two tubes) - Chris O 06:38:45 03/25/02 (6)

Re: How to design a passive single-network RIAA (two tubes) - freddyi 10:35:48 03/25/02 (2)

Re: How to design a passive single-network RIAA (two tubes) - Kurt Strain 10:54:54 03/25/02 (1)

Re: How to design a passive - botched equation - White CF? - freddyi 11:41:58 03/25/02 (0)

Re: How to design a passive single-network RIAA (two tubes) - Kurt Strain 06:52:18 03/25/02 (2)

results - Chris O 13:20:50 03/25/02 (1)

Re: results - Kurt Strain 13:29:53 03/25/02 (0)

Good job, a keeper, thanks, NT - Scholl 03:39:47 03/25/02 (0)

Re: How to design a passive single-network RIAA (two tubes) - 813 00:10:22 03/25/02 (0)

Follow Ups

Re: How to design a passive single-network RIAA (two tubes) - Kurt Strain 03/25/0212:45:38 03/25/02 (0)

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