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Post by ruger9 on Nov 18, 2006 19:25:16 GMT -7
Posted this in a couple other forums, because it kind of crosses lines between an AMP question & a SPEAKER question...
I found this in another thread (posted by billyguitar): "Some people say that at 16 ohms you're using the whole transformer and it should sound better. I believe that the lower impedance ratings use taps that don't use the whole transformer. "
And was wondering if it's true, because I'm going to be buying a Z head in the (hopefully) near future, but I'll probably be getting a cab somewhere else & loading it myself... in order to pick the right ohm speakers & wiring, I was curious if the above statement was true? "using the 'whole' transformer" certainly sounds like a better idea...?
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Post by Curt on Dec 7, 2006 6:57:08 GMT -7
I'd like to hear from Doc and Myles on this.
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Post by DRZ on Dec 8, 2006 16:14:02 GMT -7
I'd like to hear from Doc and Myles on this. I bet you would Curt. Well first yes an Output Transformers Impedance is determined by what is called a "turns ratio" . The primary impedance or the tubes plate load is determined by the reflected secondary impedance and speaker load. Each tube type has an optimum plate load, at this optimum plate load ( or AC resistance ) the tube will transfer MAX output wattage and widest frequency response. As we know this may or may not yield the best GUITAR TONE, but will yield the highest spec for pure Audio Output. Some times depending on tube type these two are equal and other times they are not. So for now lets just leave the world of Inductance, Reactance, and Magnetics, and look at output transformers taps. To answer one of your questions the relationship of the taps is pretty equal 16 on end and 8 in the middle and 4 is the shortest, but Interleaved transformers do use different winding patterns and it's not as easy as just number of turns. As for the best sounding tap on a OT it depends on the design. In Marshall Drake OT's the 16 ohm load is said to be the sweetest. But in all the testing I have done I found that the speaker it self will cause the BIGGEST change in TONE. It is nearly imposable to have say three 12" Celestion speakers each one a different Impedance, 4,8,16 all three with the EXACT same response so you can test each OT tap . So the answer I give to this often asked question is the speaker cab makes the most difference in tone and use the correct output tap on the cab that sounds the best to you. Yes another URBAN legend laid to rest. DR.Z
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Post by ruger9 on Dec 8, 2006 17:34:33 GMT -7
Thanks Doc! It's always such a pleasure to have the experts (you & all the others that frequent here...what a forum!) chime in on this type of stuff. The rest of us may THINK we know the answer, but don't have the years of experience you guys do.
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Post by billyguitar on Dec 8, 2006 17:49:28 GMT -7
I don't mind laying that legend to rest. If there is any difference it must be small. Amps with good transformers seem to sound good on all the taps. I had read that legend in at least two different books but once again, it's the real live application that is the most important. Not necessarily the theoretical ideal.
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