Inductance Compensation - for Tube-Amps in speaker crossover

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ubxf

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Hello,
I hope i'm not posting this in the wrong place. I'm building some speakers that have an optional  "Inductance Compensation - for Tube-Amps" in the crossover.
I intend to use those speakers with a Mcintosh MC 275 but i'd like to use them also with a solid state amp. Should i make that part of the circuit external so i can bypass it if not needed or add a switch? i never realized this existed or was needed before
 

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abbey road d enfer

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ubxf said:
Hello,
I hope i'm not posting this in the wrong place. I'm building some speakers that have an optional  "Inductance Compensation - for Tube-Amps" in the crossover.
I intend to use those speakers with a Mcintosh MC 275 but i'd like to use them also with a solid state amp. Should i make that part of the circuit external so i can bypass it if not needed or add a switch? i never realized this existed or was needed before
The MC275 is a very peculiar tube amp, with a topology that makes it almost impervious to loading effects, like a solid-state amp.
You should not need inductance compensation in both cases. But if you want to make your speakers usable with "ordinary" tube amps, you need it, or not. It depends on how much the impedance varies with frequency, and your expectations and taste.
HiFi enthousisats swear by a pair of 300B's with no NFB driving a Voice of the theater, which impedance varies significantly, particularly at resonance of the bass-reflex loaded woofer and at HF, when the inductive action of the driver increases it.
The result is increased bass at resonance and gradually rising HF response, which many like, and is often considered the "tube sound" by aficionados.
Step one: measure the peaker iimpedance vs. frequency.
Then you know what to expect if the output impedance of your amp is relatively high, compared to the nominal impedance. If you know the damping factor of your amp, a factor 10:1 results in approximately 1dB variation at resonance. Some amps have a much lower damping factor. A damping factor of 2 results in about 4-5dB variation of the frequency response.
 

ubxf

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Joined
Sep 3, 2004
Messages
560
Location
los angeles
Thank you so much, the only other tube amp i have is a Bogen MO 200A but i probably wouldn't use it with these speakers. I will re read your post a few times and study :)
 

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