rebiasing from 4 to 8 ohms?


Hello
I am new to tube biasing.I was curious if i will need to rebias my tube amp if i were to start using the 8 ohm taps and different speakers?I was using the 4 ohm taps and am going to be using an 8 ohm set up soon.Thanks!!
seekburk
No. Biasing the amps has nothing to do with which taps you choose to power your speakers.
I basically agree with Newbee but the stability of the design may have something to do with this. Some "bottleheads" may find this far-fetched, but it will never hurt to check such things just to be sure. Once you've done so, you know what to expect in the future. Sean
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The purpose of the transformer is to make all speaker loads look the same to the tubes. The tubes don't know what the final load is, so bias should not be speaker load sensitive.
El: The isolating and impedance coupling benefits of output transformers only work in theory, not reality. Since there are no speakers / drivers made that maintain a consistent impedance and level of reactance across the audible range of operation, the load that the transformer sees and therefore the tubes load into varies with frequency. That's why getting rid of the huge inductor located smack dab between the tubes and the drivers cleans up the sound so much. That is, if the amp is built and designed robust enough to deal with the speakers being used. This is besides the fact that the transformers themselves introduce non-linear distortions into the system. Sean
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Sean...The frequency-sensitive impedance variation seen by the tubes will be the same for 4 ohm as for 8 ohm speakers (assuming the speakers have similar characteristics). The transformer makes different impedance speakers look the same. It does not make them look like resistors.