Fearful midrange crossover question 12/6/1 troubleshooting question

[Doug Parent]

After a freak occurrence (which still has me shaking my head how it happened) that resulted in an extremely loud high frequency feedback screech, the 6" mid and 1" driver blew.

So I replaced the 6" and the ASD1001 tweet and noticed the 6" mid was now straining and fuzzing, sure enough seems like the band pass section on the Fearful cab seems to be now also passing lower frequencies through to the mid driver.

Is it possible I burned out a component on the crossover board during the high pitched feedback? I think caused by my walking around the back of the cabinet while holding a bass with the volume cranked, and perhaps the electronics on the bass where interacting with crossovers?

However the crossover is still passing signal. Seems it would make sense if something failed the circuit would be open?

I do have a multi-meter on hand.

Curious your thoughts on the matter.

 

[agedhorse]

Yes, it’s entirely possible that you damaged the series cap that’s part of the high pass section of the band pass mid filter. It’s unlikely that you damaged the shunt cap, but still possible

 

[Doug Parent]

Yes, it’s entirely possible that you damaged the series cap that’s part of the high pass section of the band pass mid filter. It’s unlikely that you damaged the shunt cap, but still possible

ah ha... okay now I know. Thanks!

 

[Doug Parent]

yup.

 

[agedhorse]

Ummm, yup. Educated, experienced “guess”.

 

[Doug Parent]

Ummm, yup. Educated, experienced “guess”.

I tried Isopropyl but the glue won't soften. cant see the specs on the other cap.

 

[agedhorse]

I tried Isopropyl but the glue won't soften. cant see the specs on the other cap.

Don’t know what kind of glue that is.

 

[Passinwind]

yup.

You might want to upgrade those caps to the correct spec, they should be polypropylene film ones rated at 250V or better IIRC. Can’t get to my PC right now to check that though.

 

[Doug Parent]

You might want to upgrade those caps to the correct spec, they should be polypropylene film ones rated at 250V or better IIRC. Can’t get to my PC right now to check that though.

if you happen to know the values I would be much obliged.

 

[Wasnex]

if you happen to know the values I would be much obliged.

You can download the plans to include the crossover circuits here:

https://www.speakerhardware.com/prodimages/fearful%20plans/12+6.zip

The CBG crossovers are in the root folder. The root folder also has an additional zip folder for the True Crossovers.

 

[74hc]

yup.

I heard of losing the magic smoking, but in that case it looks like the cap lost it's magic fur.

 

[12bass]

yup.

Barely a flesh wound!

Must have been quite the peak to take out the capacitor and both drivers.

 

[Doug Parent]

Barely a flesh wound!

Must have been quite the peak to take out the capacitor and both drivers.

I merely walked around the back side of the cabinet to adjust the L-pad. The volume was up and I was holding the bass and it started a very loud feedback squeal that smoked it. The amp is an older GK MB800. I'm wondering if the orientation of the pickups in relation to the crossovers inside the cabinet caused an interaction. And I had just gotten done re-loading the drivers and fired it up.....boom. If I would have had any beer in the fridge that moment I would have taken a long break. I was SO pissed. If anyone has any idea what caused the feedback I'd be all ears.

 

[220_Hz]

I merely walked around the back side of the cabinet to adjust the L-pad. The volume was up and I was holding the bass and it started a very loud feedback squeal that smoked it. The amp is an older GK MB800. I'm wondering if the orientation of the pickups in relation to the crossovers inside the cabinet caused an interaction. And I had just gotten done re-loading the drivers and fired it up.....boom. If I would have had any beer in the fridge that moment I would have taken a long break. I was SO pissed. If anyone has any idea what caused the feedback I'd be all ears.

Are you playing a bass with single coils?

 

[Doug Parent]

Are you playing a bass with single coils?

no. soap bar HC.