This really sounds like a crossover issue; here's something to consider

OTL Asylum

OTL, Output Transformerless Amplifier User Group.

Posted by Ralph (M) on May 12, 2023 at 10:47:27

In Reply to: RE: You may not have an output coupling cap- many OTLs don't. posted by lotsmorebetter1 on May 12, 2023 at 10:32:18:

If you don't crossover the woofer its impedance will be in parallel with that of the midrange 'full range' driver.

OTLs generally don't like lower impedances. If you have 8 Ohm drivers, the speaker will be nominally 4 Ohms thru the 'full range' driver region.

I know 'full range' driver guys don't like crossovers. But the simple truth is 'full range' drivers deserve the quotes because there really isn't any such thing (else you'd not be trying to use a woofer). If the woofer is active at higher frequencies, you'll get combing effects as the woofer is alternately in phase and out of phase with the other driver. The ear interprets this sort of thing as harshness.

So use a crossover. Getting the bass off of the 'full range' drive is a good idea, since that reduces Doppler Effect distortion.

The crossover will help linearize the impedance curve, which will make for an easier load for the amplifier. A ZOBEL network really has nothing to do with it!

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Follow Ups Full Thread

Topic - otl amps/speakers and zoebel networks - lotsmorebetter1 18:44:01 05/08/23 (8)

You may not have an output coupling cap- many OTLs don't. - Ralph 10:27:02 05/11/23 (7)

RE: You may not have an output coupling cap- many OTLs don't. - lotsmorebetter1 14:17:30 05/11/23 (6)

RE: You may not have an output coupling cap- many OTLs don't. - lotsmorebetter1 10:32:18 05/12/23 (4)

This really sounds like a crossover issue; here's something to consider - Ralph 10:47:27 05/12/23 (2)

RE: This really sounds like a crossover issue; here's something to consider - lotsmorebetter1 13:36:11 05/12/23 (1)

You'd really have to build and measure it - Ralph 13:56:11 05/12/23 (0)

RE: You may not have an output coupling cap- many OTLs don't. - lotsmorebetter1 10:33:40 05/12/23 (0)

That's correct. - Ralph 09:03:52 05/12/23 (0)

Follow Ups

This really sounds like a crossover issue; here's something to consider - Ralph 10:47:27 05/12/23 (2)

RE: This really sounds like a crossover issue; here's something to consider - lotsmorebetter1 13:36:11 05/12/23 (1)

You'd really have to build and measure it - Ralph 13:56:11 05/12/23 (0)

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