|
Tubes Asylum Questions about tubes and gear that glows. FAQ |
|
|
|
Tubes Asylum Questions about tubes and gear that glows. FAQ |
|
In Reply to: SET vs. Ultra Linear/Push Pull??? posted by Sordidman on April 20, 2002 at 15:45:40:
Hello sordidman,I am also a tube beginner so be warned, I might have misunderstood some things! Here´s my understanding though:
SET is an abbreviation for Single Ended Triode as you say.
Triode, tetrode and pentode are types of vacuum tubes. A triode is a vaccum tube with three active elements: anode, cathode and in between them a grid. The current through the valve (from anode to cathode) can be controlled by applying a varying voltage on the grid.
Tetrodes and pentodes have additional grids compared to the triode.
The tetrode has a fourth electrode inserted between the anode and the control grid (I think its called a screen) in order to lower the capacitance in the tube. It seems tetrodes are rarely used in audio amplifiers but I don´t really know why. Beam tetrodes (KT88 et al) have included a pair of electrodes to "direct" or "focus" the flow of electrons towards the anode to lower the amount of electrons bouncing back (secondary emission) to the screen thereby creating a current flow from anode to screen.
Pentodes (6550, EL34...) have yet another grid, the supressor grid, inserted between the screen and the anode. The function of the supressor grid is to make sure that the electrons bouncing off the anode do not reach the screen grid.
To confuse us newbies even more, the designers have found that beam tetrodes and pentodes can be connected in triode mode... i.e. they are working as a triode even though they have the extra electrodes for working as a beam tetrode / pentode. Some say they sound better connected this way but the available output power usually goes down.
Ultralinear, push-pull, single end, parallell single end are all configurations of the circuit in which the tube works.
One tube driving one speaker means the configuration is single end. Two (or more?) such tubes in parallell gives you parallell single end. Two parallell output tubes means double the output power. In a push-pull configuration (always tubes in pairs) one tube gets a negative input at the same time as the other tube gets an identical positive input (one tube pushes while the other pulls). In this configuration the even order harmonics are cancelled so that the output power becomes more than double that of a single tube.
Ultralinear is a configuration where a connection is made from a special winding on the output transformer to the control grid of the tube(s) so that a certain level of feedback is obtained. This is supposed to give lower disortion and a flatter frequency response. Ultralinear can be used push-pull or single ended.
Hope that helps!
Regards,
mikke
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Re: SET vs. Ultra Linear/Push Pull??? - mikke 04/21/0203:55:34 04/21/02 (4)
- Ultra Linear--correction - JJ Analog 15:51:59 04/21/02 (1)
- Thanx! (nt) - mikke 22:54:42 04/21/02 (0)
- Thanks a lot Mikke.... - Sordidman 12:18:25 04/21/02 (0)
- Thanks Mikke, - stevenk 05:04:30 04/21/02 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]