Mar 24, 2022 · You have a source resistance, a shunt choke, a series capacitor, a loaded choke (transformer and speaker). If you pick these values poorly you get a saggy or peaky response.

A solution can be the PARAFEED principle. Here, the tube is loaded with a choke. This choke has no other function as to pass DC current, and for the rest be a high resistance of whatever value, as long as it is high. From the audio point of view, to the choke are little requirements, because linearity plays not role any more!

Mar 19, 2012 · Hi Jim, Here's Paul Joppa's Rule of Thumb crica Dec. 2007: Parafeed cap: C = 2*L/ (RL squared). C is the capacitance in microfarads (uF), L is the plate choke inductance in henries, RL is the nominal load resistance in kOhms. Example: for the Paramour upgrade, L=40 henries, RL=3K, C=8.9uF.

Sep 27, 2014 · I contrast, the parafeed topology keeps the inductor (choke), but forgoes the shunting capacitor to ground, relying on the inductors high inductance to shield the triode's …

Feb 21, 2020 · In a choke-loaded parafeed setup, there are 2 paths to signal ground: (1) plate -> parafeed cap -> output transformer (OT) -> cathode bypass cap -> ground; and (2) plate -> plate choke (PC) -> last PSU cap -> ground.

Jul 31, 2014 · The "parafeed" (parallel feed) uses a large choke to provide the DC voltage to the anode. This choke must be large in value, and provides a relatively high impedance at audio frequencies. The output transformer is capacitively coupled to the anode.

May 25, 2021 · The plate choke self-capacitance is in parallel with its inductance; at resonance the impedance approximates infinity. (At high frequencies, the capacitance is also in parallel with the OPT self-capacitance, which is usually several hundreds of pF.)

An alternative to the resistor load is a choke load. A choke is basically a transformer with a single winding. Chokes have fairly low DC resistance, but present a high impedance at AC. However, the impedance of a choke is dependant upon frequency, and as such an appropriate choke must be selected to work at the frequencies that one cares about.

Nov 15, 2007 · Am thinking of doing a 2a3 parafeed amp, using a 5670 for a driver. I will have a custom wound plate choke. How do I determine the optimum plate choke inductance for the 2a3 in parafeed circuit? Thanks. Have not tried it for poweramps though. Voltsecond has a webpage and Excel-based calculator here. Not open for further replies.

Nov 3, 2004 · The parafeed design places the output valve in the mode of operating as an active shunt to the power supply applied to the output xfmer. Like a shunt regulator stage if you will …