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Vintage threads from the first ten years
Wrong Impedance vs. Tone...
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 7/21/2000 12:30 PM |
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Deltablues |
Wrong Impedance vs. Tone... The idea that Fender transformers can handle a 100% impedance mismatch seems to get posted quite frequently. (ie, an amp expecting to see an 8ohm load from the speakers can run at 4ohms or 16ohms safely). I've never done this myself, I always use the right impedance for efficiency reasons, along with the fact that I don't like stressing out 40 or 50 year old transformers. But from a purely "tonal" perspective. What difference in tone would be expected from using a 100% mismatch both higher and lower than expected? |
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| 7/21/2000 12:57 PM |
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| Liam |
Much less than you'd think. The volume difference is pretty small too. For the potential damage to valves and transformers I've generally found it not to be worthwhile on my Marshalls. Any different for Fender amps anyone? |
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| 7/21/2000 2:09 PM |
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| Ted Pimm |
I am playing a 8ohm load (4x32ohm 10" CTS's) out of my BF-Bassman and it is my impression that max. volume reduction is perceivable with this mismatch.. Also there is a sort of heavy damped feeling. |
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| 7/21/2000 2:32 PM |
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| jrem |
All the Fender guys generally say that the Fender OT's can handle 100% load mis-match without much sweat. I always try to keep it matched, but figure they put those speaker extension jacks on a lot of amps without an impedance selector. They must have been thinking something, right? |
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| 7/21/2000 11:01 PM |
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| Ken Gilbert |
db, i've had some good luck putting a heavier than expected load on the tubes... i.e. a 4 ohm load on an 8 ohm tap. as you start to crank it up it seems to have a bit more grit and grind to it; i suspect you are hearing the additional THD caused by the mismatched load itself. heavier loads will cause greater current swings and smaller voltage swings at the plate. it also results in less screen current. these factors may have something else to do with it. i don't like the sound of "lighter" loads as much as "heavier." ken |
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| 7/23/2000 9:21 PM |
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| Richie{~}==::: | Don't try this with a Marshall amp.. they are very sensitive to mismatch loads.. Richie{~}==::: |
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| 7/23/2000 11:37 PM |
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| Peter S |
Amen Richie! |
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