Don't know; I never bothered trying both. If you're really interested, you can try both & see what you think.
This is not the case for any amp I can think of (well, except those home-brew amps where the builder does it wrong
).
you are correct, had a little brain fart there. I probably have built such an amp though!Don't know; I never bothered trying both. If you're really interested, you can try both & see what you think.
This is not the case for any amp I can think of (well, except those home-brew amps where the builder does it wrong
Usually the negative feedback is tied to a single tap, such as the 8Ω tap in this 50w Marshall. All taps have voltage present when you play, so even if the speakers are on the 4Ω or 16Ω tap the 8Ω tap still has the same voltage present as it does when being used.
What this means is the same amount of feedback gets applied to the amp regardless of which speaker tap is used, which also means the amp has a consistent sound (and the Presence control has consistent performance across all the taps).
thanks, hbp. i can’t a/b it without re-rewiring the cab. really just curious about the diff (if any) between using all of the xformer windings or part of them.
Understood.
I'm very skeptical about the assertion that 16Ω uses "all of the windings" while 4Ω only uses "part of the windings." As I pointed out above, every tap on the OT is energized when you play regardless of whether a speaker load is attached. If anyone doubts this (and doesn't own a meter), we can take a power transformer and only hook up the tube heaters to the 6.3vac winding then see if they're will to grab hold of the unused high voltage winding!
much appreciate the comments. i am pleased with the results of my rewire, and will leave it in place. awaiting delivery of a suhr corso, this will allow me to run either the blue or the alltone and have a correct load. and the todd sharp sounds great @4 ohms parallel. thx again...Understood.
In a way, I'm hoping you rewire to try it out. I suspect you'll get done with the re-wire & test only to say, "I'm not sure if I heard a difference or not."
I'd suggest if it's not a huge difference (and obvious to you after taking 10-20 minutes to re-wire the cab & try it), it the same as "no difference" (meaning any difference is small enough to not warrant choosing one over the other).
I had a similar situation when swapping the neck on my Tele. I made the change for playability, because my taste in what constituted a good neck shape changed over time. It was at least a 30-45 minute process changing necks & re-stringing. But there were some other differences about the new neck, and it was immediately obvious even after the time lag that the new neck sounded profoundly different than the old one (and fortunately better).
I'm very skeptical about the assertion that 16Ω uses "all of the windings" while 4Ω only uses "part of the windings." As I pointed out above, every tap on the OT is energized when you play regardless of whether a speaker load is attached. If anyone doubts this (and doesn't own a meter), we can take a power transformer and only hook up the tube heaters to the 6.3vac winding then see if they're will to grab hold of the unused high voltage winding!
However, I don't own an amp with 4/8/16Ω taps so I haven't tried this myself. I do have some old Vox amps with 8/15Ω taps, but use 2x12 cabs at either 8Ω or 16Ω total depending on the impedance of the individual speakers (and it would be a fair test to juggle between the 8Ω & 16Ω cabs because the speakers themselves are different-enough to be different-sounding).
I don't get the "use all of the windings" hypothesis either. If you have an OT that only has a 4 ohm tap, then you're using all of the windings. It's the same winding ratio as the multitap OT, so why would it be any different? Can the extra "unused" portion in any way hamper induction to the "used" portion just by having more wire "in the way"? I'm struggling to understand the implication.Understood.
In a way, I'm hoping you rewire to try it out. I suspect you'll get done with the re-wire & test only to say, "I'm not sure if I heard a difference or not."
I'd suggest if it's not a huge difference (and obvious to you after taking 10-20 minutes to re-wire the cab & try it), it the same as "no difference" (meaning any difference is small enough to not warrant choosing one over the other).
I had a similar situation when swapping the neck on my Tele. I made the change for playability, because my taste in what constituted a good neck shape changed over time. It was at least a 30-45 minute process changing necks & re-stringing. But there were some other differences about the new neck, and it was immediately obvious even after the time lag that the new neck sounded profoundly different than the old one (and fortunately better).
I'm very skeptical about the assertion that 16Ω uses "all of the windings" while 4Ω only uses "part of the windings." As I pointed out above, every tap on the OT is energized when you play regardless of whether a speaker load is attached. If anyone doubts this (and doesn't own a meter), we can take a power transformer and only hook up the tube heaters to the 6.3vac winding then see if they're will to grab hold of the unused high voltage winding!
However, I don't own an amp with 4/8/16Ω taps so I haven't tried this myself. I do have some old Vox amps with 8/15Ω taps, but use 2x12 cabs at either 8Ω or 16Ω total depending on the impedance of the individual speakers (and it would be a fair test to juggle between the 8Ω & 16Ω cabs because the speakers themselves are different-enough to be different-sounding).
But the voltage across the speaker coils remains the same, otherwise power would change.
Remember, the speaker impedance is different, so voltage must also be different to maintain same-power. If you double the tap-impedance, voltage increases by √2.But the voltage across the speaker coils remains the same, otherwise power would change.
That's what the switch matches.
But the speaker only responds to power since speaker load must be increased if you need to change the impedance on the amp.
You don't get more cone movement without more power.
I'm talking about fundamental properties of transformers, and a single output transformer with multiple secondary taps (4/8/16Ω). If you play through such an amp/OT, at any single moment the 4Ω tap has the least voltage present, the 8Ω tap has √2 more voltage present, and the 16Ω tap has 2x the voltage present as on the 4Ω tap.
Now be aware my assertions here do not imply support for Eugene's assertion that you also quoted. I don't know anything about "Speaker cone travel." Nothing I've said should be "controversial."
The Navy taught me Ohm's Law in a very specific way. Our homework one night was to write the following 100 times on a sheet of paper:
For myself, I haven't delved into the depths of what details of a speaker's construction makes do whatever, because I'm don't expect I'll ever scratch-build a speaker or have any real way to alter how the speaker does what it does. I dig into how the parts of the amplifier do what they do, because those are what I do build, modify, etc.
This sounds like B.S. to me.
Gotcha! I thought, "this does not read right," referred to what I posted, rather than what you quoted Eugene quoting.
