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Re: Then questions

Hi, it's a honor to receive a post from THE Gordon Rankin.

My autoformers, which are custom wound by David Slagle, work perfectly on any power amp with an input impedance higher than 10 K ohms. That's at maximum volume, which is the worst case scenario.

Also, restacking the laminations to reduce the gap will make the autoformer work perfectly into lower impedances like 5 K (e.g. Pass amplifiers).

As one decreases the volume, the CDP's reflected output impedance will go down as a function of the square of the turns ratio.
A typical CDP output impedance of 100-200 ohms will most of the time behave as 10 ohms source driving 10,000 ohms load, an almost ideal impedance ratio (anything above 10:1 is fine, in my preamp it's 1000:1).
Autoformers perform attenuation in two ways: ratio of inductive reactances and ratio of coil resistance. There is a direct DC path between input and output, which IMO makes a whole lot of difference.
My system goes flat in-room to 20 Hz, my tubed CDP outputs 7 Volts, I have never heard any signs of bass roloff or saturation at any decent volume setting.
Some TVCs do saturate above 5-6 V input at very low frequencies. There's a white paper on S&B's site with frequency x distortion charts, therefore you are correct on the inductance issue, it happens, but not with Dave's autoformers.
All the best
Carlos


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