4 ohm vs 8 ohm taps
Eldartford, you know of course that the secondary on the transformer has different taps, 4, 8 and 16 to match the speakers. Those taps simply have different amount of winding to 'transform' the primary winding impedance which is constant. The tubes themselves don't see the secondary taps or impedance. Salut, Bob P. |
[email protected] have it backwards. The different taps of the transformer secondary make it possible for the tubes to see the same (high) impedance with different loads. Here is a way for you to test your theory. Short out the speaker terminals of your amp and drive it hard. If your theory is correct, the tubes won't see the short. After the fire department has left, post results of this experiment :-) |
Eldartford, exactly - the tubes do not see the difference of what is connected to the secondary taps or to which taps the speaker is connected. The poster that said that connecting the speakers to the 'wrong' tap would make the tubes 'see' a different load and thus distort their output. The reason that the amp overheats when shorting the speaker taps is due to the tranformer trying to drive a 0 inpedence load and thus drawing more power from the tubes on the primary side. It has nothing to do with the impedence changing on the primary (which doesn't), which the tubes 'see'. Salut, Bob p. |
[email protected] can you say that a zero ohm load is "seen" through transformer coupling, but yet loudspeaker loads are not? In another area, when you use a step up transformer for your moving coil phono pickup it can be connected to a standard MM preamp input, 47K input load, and still present the proper loading of a few hundred ohms on the pickup. The loading applied to the secondary is "seen" through the turns ratio of the transformer. . |
