Using an amp's multi-tap output capability

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TylerSavage wrote:I think there's a lot going on there, and probably more a speaker thing vs. an amp tap thing.You might be right. I'm pretty sure we are on the same page, but for the sake of added clarity: the majority of my questions are in regards to using the same amplifier and same speakers at a different overall (but matching) load. Example: modern 1960A/1960B cabinets have a switchable impedance, just like a lot of heads. Lots of other modern cabs do as well. I have the option of running my cab at either 4 or 16 ohms with several heads that are switchable as well.

Using an amp's multi-tap output capability

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I should keep it simple. Open to all discussion related to this topic, but I'm mainly looking to find out the answers to the following questions:1) Assuming you are matching the amp and speaker loads, is it any safer to run an amp 16 ohms vs 4 ohms since you are using more of the windings? Or vice versa?2) Does the 4 ohm tap sound any different than the 16 ohm tap, and if so, why/how?

Using an amp's multi-tap output capability

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I'm curious what is fact, and what other's opinions are on using the same amp with different selectable output impedances.Most Marshall dudes use their amps at 16 ohms. I assume this started because the old cabs were hardwired this way. But I'm curious if anyone else hears tonal differences and what's actually happening if there are. Does the tap with the negative feedback tied to it sound different? I'm also curious if there is a safest setting when running amps hot. I've personally almost always used 4 ohms because I was used to that from Fender, and most of my cabs used to be 4.From my own experience with an OR120, it would seem that tonally the 4 ohm setting sounds a little punchier than the 16 ohm. 16 ohm sounds a little more compressed to my ears. It's subtle, but it's there. Have other people experienced similar?Related: I know that running a pair of speakers parallel vs series is safer because if one blows you still have a load. From my own testing it also seems that running a pair of different speakers in series has the tonal effect of smoothing out the two slightly. But maybe I imagined that. Not sure the effect would be as great with a 4x12 since the difference is either series/parallel vs all parallel.Thoughts?

Using an amp's multi-tap output capability

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Tommy wrote:TylerSavage wrote:I think there's a lot going on there, and probably more a speaker thing vs. an amp tap thing.You might be right. I'm pretty sure we are on the same page, but for the sake of added clarity: the majority of my questions are in regards to using the same amplifier and same speakers at a different overall (but matching) load. Example: modern 1960A/1960B cabinets have a switchable impedance, just like a lot of heads. Lots of other modern cabs do as well. I have the option of running my cab at either 4 or 16 ohms with several heads that are switchable as well.Yeah that does change whether the speakers are in parallel vs. series, which for the sake of guitar playing I doubt anyone could actually hear any difference in, especially considering each speaker in one of those cabinets has the same impedance, they should be seeing the same voltage.So to conclude, I have nothing to offer of value.

Using an amp's multi-tap output capability

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as for safety/reliability what do you want to save?speak,trans or valves? does not matter; clipping could be considered abuse to all and if one fails could be like dominos. a fuse may help.more windings has more capacitive coupling from pri to sec. more inductive coupling from core to sec..all theoretical and not matter as the system is dynamic and has so many variables--let the ear decide

Using an amp's multi-tap output capability

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TylerSavage wrote:For 50 Watts at 4 ohms the speaker draws about 3.5 Amps of currentFor 50 Watts at 16 ohms the speaker draws about 1.75 Amps of currentThis is interesting info. I'm not totally sure what it means, but it might mean the output transformer is working harder at 4 ohms?TylerSavage wrote:Tonal differences may also be attributed to heating effects, or possibly magnetic saturation in the speaker as well. I m not sure about the exact reasons for the tonal differences, but they are there. "This makes sense. I wonder if the shift is notable at this level though, given identical speakers.

Using an amp's multi-tap output capability

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Tommy wrote:I should keep it simple. Open to all discussion related to this topic, but I'm mainly looking to find out the answers to the following questions:1) Assuming you are matching the amp and speaker loads, is it any safer to run an amp 16 ohms vs 4 ohms since you are using more of the windings? Or vice versa?2) Does the 4 ohm tap sound any different than the 16 ohm tap, and if so, why/how?I spoke with the head electrical engineer at my work (he's designed amps), and his thought was to keep it simple as well:"One main difference might be how the speakers respond to the higher current levels with the lower ohm impedances.For 50 Watts at 4 ohms the speaker draws about 3.5 Amps of currentFor 50 Watts at 16 ohms the speaker draws about 1.75 Amps of currentTonal differences may also be attributed to heating effects, or possibly magnetic saturation in the speaker as well.I m not sure about the exact reasons for the tonal differences, but they are there. "

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