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In Reply to: Chokes posted by DrM on August 16, 2001 at 12:44:45:
How do you heat the filaments? Are you using ac, or if using dc are you using chokes, current regulators, or voltage regulators?Do you use separate transformers for driver, output, filaments?
Retsel
Follow Ups:
Dan is using current regulation on both driver and output tubes, with a battery supplying a floating current supply for the 26 heaters, and rectified and filtered AC for the output current supply.I am using the same battery powered current regulated supply for the 26 driver but am AC heating the outputs with hum nulling pots. Dan drives the speakers full range with the SS subwoofer amp taking its input from the speaker terminals of the ORIS horn (so the 71A's have to perform full range pretty much) and I run line in to my subwoofer amp and let the ORIS just run 150 Hz on up with the 71A's.
Kurt
Kurt, have you ever built such a beast? I'm looking to move away from the line level as you are using and move to the speaker level as Dan is using, but I would like to be able to choose my sub amp, so i would like to build my crossover external.... any ideas, opinions? Is it just a speaker level crossover with the speaker load replaced by a 50k pot for level adjustment?Thanks.
Peace,
Jeffrey
The subwoofer amps we use have an option of either line level input or speaker level input. Either way the crossover is the same, op amps used to create a 2nd order low pass with variable crossover frequency (40-200 Hz) and gain. The impedance can be anywhere from about 200 ohms to 50K for speaker in level. I have no other details since I didn't design the sub amp, and I'm not sure what I would rather do if this solution didn't already work so good.Kurt
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