Crate KX-160 KX160 Noise Help

[J M Fahey]

Reread post#11, it says exactly the same:
* wires straight to woofer ... check
*wires to tweeter through crossover (Capacitor/Resistor/inductor) ... check

Not sure about the actual situation today, is it working or not?
Have you replaced the diaphragm?

It won't work until you do so, that's for sure.

IF you want to test the crossover NOW without waiting for a new diaphragm connect a speaker, *any* speaker to tweeter send terminals, you should hear highs through it.

[misterc57]

Diaphragm is on order. Great idea to connect another speaker to test the board! Will do that.

Anyway, if anyone is interested I have attached some pics of the crossover. The outer black/red wires feed the woofer, the inner black/red feed the tweeter.

Thanks

[misterc57]

woofer

Back to the woofer. I tried moving the cone in/out and I do not hear any rubbing. I also thumped it a few times and no odd sound.

Will do more testing after the tweeter is repaired.

[Enzo]

You can test the speaker by connecting it directly to the amp. NO crossover, no tweeter.

[misterc57]

So I tested the crossover tweeter feeds to another speaker and it works. Bad news is that I am hearing my original noise issue.

I had thought I did not hear the noise issue when testing the amp to another speaker cab. Looks like I was wrong. The noise is sometimes obvious and at other times it is not.

So I am back to square one on this issue and need to do more testing to see if I can isolate the section that is causing the noise.

The noise is a crackling sound.

Thanks!

[J M Fahey]

Connect a plain speaker to head output, no crossover/tweeter/nothing else ... do you still hear the crackling noise?

[misterc57]

Connect a plain speaker to head output, no crossover/tweeter/nothing else ... do you still hear the crackling noise?

Did that, no crossover, direct to 15" speaker. Still crackling, also notice volume slightly jumps up/down as well. These issues are apparent on all the input channels. Sounds like a bad pot or a bad solder joint might exhibit. All the pots were cleaned. At some point I could start tracing a signal through the circuit and see if I can locate the issue but I still have not found a schematic.

Thanks!

[J M Fahey]

Ok, then it is not a speaker or crossover problem.

You need a scope to see the crackling and volume jumps.

Anything which can be seen can be heard and viceversa.

So scope the speaker output, play the "dangerous note" and tell us what happens.
If you can take a picture of the scope screen showing the glitch, even better.

[Enzo]

Without reading the whole thread again, have we tried the patch cord across the FX loop yet?

Does turning all controls to zero stop the noise?

Ball up your fist and whack the top of the amp, does that affect or cause the crackle?

[misterc57]

I found a schematic (attached) for the K-160XL which appears like it could be the same amp.

This amp has two effects loop, I will try a patch cord across each. The chassis is out of the amp so I cannot whack it but I will poke around with a chop stick. The noise only appears when playing a note, so controls to zero will have no sound or noise.

I have an old scope but never use it (means I am not proficient at using one, but I should learn). I usually run a signal and use a probe to listen for sound/no sound and sound quality through the circuit.

Thank you for all the great suggestions and help! MC

[Enzo]

You can still whack it, use a mallet and whack the end of the chassis. Or the handle of a large screwdriver. ANything to send a little jolt through it mechanically.

KX160 and K160XL are two separate files, though I don;t doubt they are similar. I'll try to look at the differences.

[misterc57]

Tried the jumpers on each and both loops, still have the noise.

Starting banging around and found that the master volume pot is jumping in/out when hit. This weekend I will pull the boards out and resolder that pot and anything else that may look suspect.

Hope I am not driving everyone crazy but here is another strange thing I noticed (maybe it is normal)... The chassis is out of the cabinet. Amp is on with no signal being sent to the amp. If I touch the top edges of the chassis I can feel a constant steady very subtle vibration. If I shut the amp off, there is no vibration. Turn it on, the whole thing has this little vibration. What could that be all about?

Thanks again! MC

[g1]

That's the normal vibration. Rub your fingertips lightly across any aluminum (or other metal) panel of a running piece of gear and you'll probably get that weird feeling.

[Enzo]

Plus a little natural vibration from the transformer.

[SpareRibs]

Hello,
You can get a schematic by contacting (Loud Technology). That is where I have obtained Crate schematics.