2. amps-preamps
  3. 153287-59357

Tube amp output taps; use both?

Dodd Audio 120 MKIIIs have both 4 and 8 ohm taps.  B&W Matrix 801s have inputs for both mid/tweeter and woofer (which I know are electrically isolated); currently bi-wiring.  Two questions: 1) Would running one set of speaker cables from 4ohm tap to woofer and one set to mid/tweeter harm the amplifier?  2) If, answer to 1 is "no", would there be any advantage to doing so with respect to lower impedance/higher damping presented to woofer?  Have tried bi-wiring from each of the two taps, and preferred the 8 ohm; "swings" better, boxers versus briefs, but did note that the woofer seemed a bit more tightly controlled off of the 4 ohm tap.  Not sure if it's safe to try the "two tap" bi-wire configuration and also not sure if doing so would impart a tonal difference between the drivers that would be counterproductive to good sound, but obviously, the first question takes precedent over the second.  

Thanks for any insights.    
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xenolith OP
120 posts
 
Thanks for the reply Ralph; you're one of the members that I know I can trust the validity of technical information from.  Your point about a coloration not found in real life is well taken; thank you. 

By tightly controlled, I meant that cone excursion seemed less on the 4 ohm tap compared to the 8 ohm tap at same volume setting on the preamp.  I admit that I could have imagined that though.

I'm very grateful and glad to know that this is a permissible experiment, but think I'll hold off on trying it...or the time being anyway.  This version of these amps are likely, if not absolutely, irreplaceable...in the near term anyway.  And as much as I do believe your information, and I do, I'm having a hard time getting over the thought of finding out that they don't work well as OTLs :)

Thanks again!


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