fEARful 12/6/1 crossover help please !!!!

Ncognito · #1 04-14-2011, 12:58 PM

Hi gang

I got a used fEARful from a fellow TBer. Upon playing thru it, I noticed nothing coming from the horn. I tried it with an old Foster horn I had laying around and a TINY bit of high end came out and the L-pad would turn the horn level up and down. I took apart the Eminence ASD-1001 and could see and smell the voice coil was toast. Got a new ASD-1001 today, put it back together and once again next to NOTHING coming out from the horn. Absolutely no audible difference with the L-pad all the way down or up. You can hear the L-pad doing its thing, but the high end is just a hiss with no high end detail or information coming out.

I want to keep the box, but I have NO IDEA how to figure this problem out. Bad film capicator, bad air core inductor?

Any advice or suggestions are very much appreciated!!!!

BurningSkies · #2 04-14-2011, 01:04 PM

Quote:

Originally Posted by Ncognito

Hi gang

I got a used fEARful from a fellow TBer. Upon playing thru it, I noticed nothing coming from the horn. I tried it with an old Foster horn I had laying around and a TINY bit of high end came out and the L-pad would turn the horn level up and down. I took apart the Eminence ASD-1001 and could see and smell the voice coil was toast. Got a new ASD-1001 today, put it back together and once again next to NOTHING coming out from the horn. Absolutely no audible difference with the L-pad all the way down or up. You can hear the L-pad doing its thing, but the high end is just a hiss with no high end detail or information coming out.

I want to keep the box, but I have NO IDEA how to figure this problem out. Bad film capicator, bad air core inductor?

Any advice or suggestions are very much appreciated!!!!

How about staring with a pic or two of the crossover network in general?

lbwdog · #3 04-14-2011, 01:38 PM

Are you testing it with a bass guitar? If so, it may be normal as there's very little content in the highest frequencies. Try it with a different sound source such as a jazz CD with some good cymbal tones. If it sounds muffled, there's a problem.

rpsands · #4 04-14-2011, 01:41 PM

The horn crossover spec'd by Duke is very high. So if you're rolling off your tone knob at all or using flatwounds or anything, it will probably not have any content at all. So keep that in mind first.

Get your laptop, a 3.5mm to 1/4" jack, and run a sine wave generator to test. That'll be much better than bass guitar for this purposes.

I'd suggest doing a slow sweep up.

Ncognito · #5 04-14-2011, 05:01 PM

Here is a pic. Hope it can be of some help!

Thanks guys.

Nick

Ncognito · #6 04-14-2011, 05:14 PM

I've used 2-way cabinets for many years (Eden 410XLT), and I'm used to the high end sizzle the horn adds. I pop/slap and use a pick a lot, so the horn is a must. My ears are pretty good and I don't hear ANY difference with this horn on or off at all. I have to put my ear against the horn just to hear the L-pad having any effect, and that is barely. Got to be something wrong. There would be absolutely no reason to add the horn to a fEARful if this one is working correctly, because it has ZERO effect.

DukeLeJeune · #7 04-14-2011, 05:56 PM

If wired correctly, I think that circuitry should have protected the tweeter pretty well, but it's possible that a poweful amp driven to hard clipping could have smoked it.

I'm sorry, but I'm just not able to figure out what I'm seeing there in the pic.

Can you send it a recorded music signal? This will be more broadband than a bass guitar signal, and will leave no doubt as to whether or not the tweeter is working as you go through a trouble-shooting sequence. Quite modest volume level will be fine for this - don't crank it.

We want to find out if the tweeter is getting the signal that it's supposed to.

Do you have a couple of resistors handy, anything between 4 and 20 ohms? Substitute a resistor for the woofer, and listen to what sort of signal is being passed by the midrange driver. Then substitute the other resistor for the midrange driver, and hook the midrange up to the tweeter wires. See what sort of signal the tweeter would be getting, and mentally compare that to what the midrange driver was getting. The reason for using the midrange driver in place of the tweeter is, if the crossover is miswired or not working properly, it won't get blown by low frequency energy that comes through.

The midrange driver should go up just as high whether it's hooked up to to the midrange wires or the tweeter wires (and maybe even a tiny bit higher on the midrange wiring because of that protective inductor in series with the tweeter). But when connected to the tweeter wiring, the midrange driver should have much less lower midrange energy coming through.

Anyway this should give you an indication of whether or not the crossover is working properly.

If the crossover isn't working properly, check it against the schematics on greenboy's site. Check for bad solder joints or broken wires. Smell the L-pad. It's very unlikely that an inductor is cooked, but a bad capacitor is possible - and it shouldn't cost much to replace if you have any doubts.

BurningSkies · #8 04-14-2011, 05:59 PM

That's a bit of a mess, innit?

I'll do my best to take a look at it once I'm home from work and my eyes aren't blurring from 10 hours in front of my monitor... To be honest, just looking at that makes me want to take it apart and neaten things up. Seems like there's some funny stuff happening too...like to iron core inductors for the low and mid sections.

Ncognito · #9 04-14-2011, 08:47 PM

I played mp3 music thru the cabinet. Next to nothing (really nothing) coming out of the horn. Strange the L-pad still is doing something, but its really only hiss coming out and no musical content to speak of.

Thank you guys for chiming in. I'm pretty crappy with soldering, but I guess I will order the correct capacitors and try them in place of what's in there. I wish there was a better solution!

BurningSkies · #10 04-14-2011, 09:07 PM

Quote:

Originally Posted by Ncognito

I played mp3 music thru the cabinet. Next to nothing (really nothing) coming out of the horn. Strange the L-pad still is doing something, but its really only hiss coming out and no musical content to speak of.

Thank you guys for chiming in. I'm pretty crappy with soldering, but I guess I will order the correct capacitors and try them in place of what's in there. I wish there was a better solution!

Start by seeing what's in the circuit. Its really hard to tell in the pictures of the values of the components. Its also hard to see if its wired correctly or if those connections are solid. The original builder could have substituted some components without a problem depending on what was used. I just know that it looks like the 12/6 spec shows an iron core and an air core, and I'm seeing two iron cores...but they could be the correct values anyway. Its a bit of a rats nest anyway and I'd want to 'tighten' it up anyway just so there's not much movement mechanically.

Ncognito · #11 04-15-2011, 05:10 AM

I compared the crossover diagram to what's in this box and everything looks right. If a capacitor was bad, could the high frequencies be dramatically reduced??

5StringPocket · #12 04-15-2011, 11:51 AM

If troubleshooting and repair is too much of a pain you could just order a replacement from Leland Crooks at
greenboy fEARful Designs | Speaker Hardware

rpsands · #13 04-15-2011, 11:56 AM

Tried taking the attenuator out of the loop?

greenboy · #14 04-15-2011, 11:58 AM

I'm horrible at long range virtual troubleshooting. But using a noise-based test signal would tell me in about .05 seconds whether the HF section was putting out content. Computers can do this, CDs are available, a lot of hardware based RTA/DSP/SMS rackmount PA stuff can.

That crossover is kinda messy, and two solid-core coils?

Ncognito · #15 04-15-2011, 01:32 PM

I ran my PA thru the fEARful with some mp3's and putting my hand back and forth covering the horn made no difference at all to my ears. If anything is coming out it's about 1/10th of what I'd expect to hear out of any horn in any bass cabinet I've ever owned.

Here is a better pic for any clever eyes out there.

I know this is a tough one, and I do appreciate the assistance guys!!!!!

Passinwind · #16 04-15-2011, 01:44 PM

Quote:

Originally Posted by Ncognito

Here is a better pic for any clever eyes out there.

What is the red and black wire on the left connector of the L-pad connected to?

Ncognito · #17 04-15-2011, 02:32 PM

Thanks Passinwind

It's an extender piece of wire going from the capacitor to the L-pad. Like the above diagram. The 2 pieces of wire in the upper left corner of the picture are soldered together. I needed some additional length when I was monkeying around with the L-pad.

Passinwind · #18 04-15-2011, 03:00 PM

OK, start by bypassing the L-Pad. Disconnect pin 2 from the tweeter and connect the wire currently on pin 3 to it directly -- not still attached to pin 3 at the same time. Any change?

Ncognito · #19 04-15-2011, 03:09 PM

Pin 3 directly to Tweeter + ???

Passinwind · #20 04-15-2011, 03:22 PM

Quote:

Originally Posted by Ncognito

Pin 3 directly to Tweeter + ???

The wire from the 2uF cap directly to the tweeter + instead of to pin 3. You can leave pin 1 to ground, nothing else connected to the L-Pad. Be conservative with your test signal input.