Will I blow anything up?


I biwire my speakers off the 8 ohm amp tap. If I instead used the the 8 ohm tap for one run (lows) and the 4 ohm tap (highs) for the other run will I blow anything up?
eddaytona
You shouldn't blow anything up but I would strongly recommend that you don't hook up the speakers in this way. It could lead to very inconsistent speaker performance as the speaker impedance varies along the frequency spectrum. Either biwire from the 8 ohm taps or from the 4 ohm taps, depending on the nominal speaker impedance specification.
Almarg, are you out there? What's your take on this.

Rgds,Clay
There will be lower voltage at the 4 ohm tap, so the woofer/tweeter gain match will be wrong.
Almarg, are you out there? What's your take on this.

LOL!

I agree with Eldartford. There may be other sonic issues as well, but I'm not going to take the time to think about them because the reason he cited makes the whole idea a non-starter by itself.

Best,
-- Al
You would really need to find out what the the impedances are for the woofer and the mid/highs separately. This configuration is similar to bi-amping as I’m assuming you are removing any jumpers at the speakers?
Did some digging; this out of an owners manual for the VAC renaissance 30/30-

"A word about impedance matching - If you bi-wire your system (run separate speaker leads from the amplifier to the high and low frequency transducers)you may discover that two different taps work best. For example, with early production Martin Logan Sequel II we find that the bass speaker is best matched with the 4 ohm tap, while the electrostatic panel is best controlled by the 2 ohm tap. On later production Sequels we use the 4 ohm connection to both drivers."

I'd recommend contacting the amp / speaker manufacturers before getting creative just to be on the safe side. Good luck
with early production Martin Logan Sequel II we find that the bass speaker is best matched with the 4 ohm tap, while the electrostatic panel is best controlled by the 2 ohm tap. On later production Sequels we use the 4 ohm connection to both drivers.

I'm pretty certain that the result of doing that (what they describe for the early version Sequel II) would be boosting the output to the bass driver by 3db, relative to the output to the electrostatic panel. Yes, that conceivably could result in subjectively pleasing sound with speaker/room combinations that are poorly balanced, but it is certainly not an ideal way to obtain accurate sound. Basically, it amounts to using the output transformer as a shelving tone control.

I'm basing that on the assumption that the transformer taps are designed to provide the same impedance to the plate circuits of the output tubes regardless of whether an 8 ohm speaker is connected to the 8 ohm tap, or a 4 ohm speaker is connected to the 4 ohm tap, or a 2 ohm speaker is connected to the 2 ohm tap (if there is one). And on the fact that the speaker load impedance is reflected in the output tube plate circuit in proportion to the square of the turns ratio of the transformer tap that is used.

Similarly, the original poster's proposed configuration would result in a 3db boost to the bass driver(s), relative to the highs. A non-starter in my book, as I had indicated, at least if the speaker/room combination is reasonably well balanced.

Regards,
-- Al
Dear Vonhakemarine and the other posters:

Thanks for the feedback. I was pitching this as theorical curiosity during a long winter's day.