Talk:Ultra-linear

Why does the article mention a screen-grid in a triode? - by definition a triode doesn't have a screen grid so this is incorrect. —Preceding unsigned comment added by 122.107.129.190 (talk) 10:29, 21 May 2010 (UTC)
 * A true triode indeed does not have a screen grid. But a pentode connected in triode mode does.  It is this latter that the article is discussing. 86.176.156.193 (talk) 09:13, 29 November 2010 (UTC)

The McIntosh Unity Coupled Circuit is fundamentally different
The McIntosh circuit was designed to eliminate DC switching pulses in the output transformers of class AB amplifiers. These pulses cause distortion which cannot be corrected by negative feedback, local or global (see Pen-Tung Sah, "Quasi Transients in Class B Audio-Frequency Push-Pull Amplifiers", Proc. IRE, 24.11, Nov. 1936).

In the McIntosh circuit, the DC component of the flux is cancelled by splitting each half primary equally between the anode and cathode of each valve. This cancels out the DC component of the flux under all conditions, unlike the usual push-pull circuit where the DC component is only cancelled out completely under pure class A conditions. The other circuits mentioned cannot achieve this.

Half the signal voltage on the primary is also returned to the screen grids and to the control grids, as well as to the cathodes, all in phase with the cathodes. This cancels out the feedback from the cathode in both the screen circuit and the grid circuit.

Therefore, in the McIntosh circuit, each valve operates like a pure pentode, unlike the Ultralinear, Quad or Audio Research circuits which feature feedback to the screen grids, or to both the screen grids (Ultralinear) or to both the screen grids and control grids (Quad, Audio Research).

Gkaraolides 14:31, 2 October 2007 (UTC)


 * What you say may or may not be correct. But since the article never introduced the point, why mention it here? 86.176.156.193 (talk) 09:13, 29 November 2010 (UTC)